1. 何良年等,绿色化学基本原理. 科学出版社,北京.(ISBN:978-7-03-057791-7,2018年6月第一次印刷.)
  1. Mei-Yan Wang,Ning Wang, Xiao-Fang Liu, Chang Qiao and Liang-Nian He*, Efficient Tungstate catalysis: pressure-switched 2- and 6- electron reductive functionalization of CO2 with amines and phenylsilane, Green Chem.2018, 20, 1564-1570. [link]

Abstract: An efficient and environmentally benign tungstate catalysis for reductive functionalization of CO2 with amines and phenylsilane was developed. By simply varying the pressure, 2-electron or 6-electron reduction of COsuccessfully approached with simultaneous C-N bond formation, thus leading to the formation of formamides and methylamines, respectively. That is, secondary and primary amines furnished the corresponding methylamines or dimethylamines in excellent yields under atmospheric pressure of CO2, while various formamides were formed in yields ranging from 52% to 98% when increasing the CO2 pressure to 2 MPa. 1H NMR studies and control experiments demonstrate that the N-formylation undergoes the formation of silyl formate while the N-methylation proceeds through an aminal intermediate generated by 4-electron reduction of CO2.

  1. Xian-Dong Lang, Liang-Nian He,* Integration of CO2 Reduction with Subsequent Carbonylation: Towards Extending Chemical Utilization of CO2ChemSusChem, 2018, 11, 2062-2067. [link]

Abstract: Currently, it still remains a challenge to amplify the spectrum of chemical fixation of CO2, although enormous progress has been achieved in this field. In view of the widespread applications of CO in a myriad of industrial carbonylation processes, an alternative strategy is proposed in which CO2 reduction to CO is combined with carbonylation with CO generated ex situ, which affords efficiently pharmaceutically and agrochemically attractive molecules. As such, CO2 in this study was efficiently reduced by triphenysilane using CsF to CO in a sealed two‐chamber reactor. Subsequently, palladium‐catalyzed aminocarbonylation, carbonylative Sonogashira coupling of aryl iodides, and rhodium(I)‐mediated Pauson–Khand‐type reaction proceeded smoothly to yield amides, alkynones, and bicyclic cyclopentenones, respectively. Furthermore, the formed alkynones can further be successfully converted to a series of heterocycles, for example, pyrazoles, 3a‐hydroxyisoxazolo[3,2‐a]isoindol‐8‐(3aH)‐one derivatives and pyrimidines in moderate yields. The striking features of this protocol include operational simplicity, high efficiency, and relatively broad application scope, which represents an alternative avenue for CO2 transformation.

  1. Xiao-Ya Li, Su-Su Zheng, Xiao-Fang Liu, Zhi-Wen Yang, Tian-You Tan, Ao Yu*, Liang-Nian He*, Waste Recycling: Ionic Liquid-Catalyzed 4-Electron Reduction of CO2 with Amines and Polymethylhydrosiloxane Combining Experimental and Theoretical Study, ACS Sustain. Chem. Eng., 2018, 6, 8130-8135.  [link]

Abstract: The acetate-based ionic liquids (ILs), e.g., [nBu4N]OAc, have been developed for challenging 4-electron reduction of CO2 with amines and hydrosilane to afford aminals. Notably, polymethylhydrosiloxane, a cheap byproduct of the silicone industry, also works well as a reductant. Furthermore, an alternative pathway is rationally proposed via thorough density functional theory (DFT) study. In addition, the ILs play a surprisingly significant role through decreasing activation free energy. More importantly, the essence of being kinetically favorable with 4-electron reduction and thermodynamically favorable with 6-electron reduction is unveiled by DFT study, which guides us to successfully get 6-electron reductive products of CO2, i.e., methylamine. This work represents upgrading usage of both carbon and silicon wastes to valuable chemicals via IL catalysis.

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  1. Xiao-Fang Liu, Xiao-Ya, Li, Chang Qiao, Liang-Nian He,* Transition-Metal-Free Catalysis for Reductive Functionalization of CO2 with Amines, Synlett 2018, 29, 548-555. [link]

Abstract: Reductive functionalization of CO2 with amines and a reductant, which combines both reduction of CO2 and C-N bond formation in one-pot to produce versatile chemicals and energy-storage materials i.e. formamides, aminals and methylamines that are usually from petroleum feedstock would be appealing and promising. Herein, we give a brief review on recent development in the titled CO2 chemistry by employing transition-metal-free catalysis, which can be catalogued as below according to the diversified energy content of products, i.e. formamides, aminals and methylamines being consistent with 2-, 4- and 6-electron reduction of CO2, respectively. Notably, hierarchical reduction of CO2 with amines to afford at least two products e.g. formamides and methylamines could be realized with the same catalyst through tuning the hydrosilane type, reaction temperature or CO2 pressure. Finally, the opportunities and challenges on the reductive functionalization of CO2 with amines are also highlighted.

  1. Xiao-Fang Liu, Chang Qiao, Xiao-Ya, Li, Liang-Nian He,* DMF-promoted reductive functionalization of COwith secondary amines and phenylsilane to methylamines, Pure Appl. Chem2018, 90(7): 1099-1107. [link]

Abstract: An amide-promoted protocol was developed for the reductive functionalization of CO2 with amines/imine and phenylsilane to produce methylamine. Various amines including aromatic and aliphatic, primary and secondary ones as well as imine were methylated successfully to methylamines with up to 98% yield under atmospheric pressure of CO2 and 80 oC. Furthermore, a tentative mechanism involving that amide-promoted CO2 reduction to the silyl acetal species was proposed. Striking features of this metal-free protocol are selective six-electron reduction of CO2 with hydrosilane as a reductant in the presence of amine.

  1. Qing-Wen Song, Ping Liu, Li-Hua Han, Kan Zhang*Liang-Nian He*, Upgrading CO2 by incorporation into urethanes through silver-catalyzed one-pot stepwise amidation reaction Chin. J. Chem.2018, 36, 147-152. [link]

Abstract: One-pot two-step stepwise reaction of terminal propargylic alcohols, carbon dioxide, and primary/secondary amines for the effective synthesis of various urethanes through robust silver-catalysed C-O/C-N bond formation is reported. Catalytic activities were investigated by controlling catalyst loading, reaction pressure and time, and very high turnover number (turnover frequency) was obtained: 3350 (35 h−1) with 0.01 mol% silver catalyst under 0.1 MPa, and up to 13360 (139 h−1) with 0.005 mol% silver catalyst under 2.0 MPa at room temperature. The strategy was ingeniously regulated, and synchronously afforded a wide range of β-oxopropylcarbamate and 1,3-oxazolidin-2-one motifs in excellent yields and selectivity together with unprecedented high turnover number (TON) and turnover frequency (TOF) value.

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  1. Chang Qiao, Yu Cao, Liang-Nian He*, Transition Metal-Catalyzed Carboxylation of Terminal Alkynes with CO2Mini-RevOrg. Chem., 2018, 15, 283-290. [link]

Abstract: The coupling reaction of terminal alkynes and CO2 provides a promising way to synthesize propiolic acids. Among the existing catalytic systems, transition-metal copper and silver exhibit excellent catalytic efficiency under mild conditions probably being attributed to the activation of C-C triple bond of terminal alkynes. In this aspect, efficient strategies for activating both substrate and CO2 are often smart choices. This review summarizes the development trend of the Cu/Ag-catalyzed carboxylation reactions of terminal alkynes with CO2, and representative examples are also discussed in detail.

  1. Jia-Ning Xie, Liang-Nian He*, Hong-Chen Fua, Ning Wang and Mei-Yan Wang, Sodium Acetate-Promoted Oxa-Michael-Aldol [3+2] Annulation Reactions: Facile Access to the Fused Heterocycle, Current Catal., 2018, 7, 60-64. [link]

Abstract: A highly active base-promoted system based on NaOAc•3H2O has been designed for the oxa-Michael-aldol [3+2] annulation reactions of internal alkynotes with N-hydroxyphthalimides, giving a series of pharmaceutically attractive 3a-hydroxyisoxazolo[3,2-a]isoindol-8(3aH)-ones in synthetically useful yields of up to 98%. Only 10 mol% NaOAc•3H2O is needed for the reaction at room temperature within 6 h. Besides, a plausible base-promoted intermolecular [3+2] oxa-Michael-aldol type mechanism is proposed.

  1. Zhi-Hua Zhou, Shu-Mei Xia, and Liang-Nian He*, Green Catalysis for Efficient Three-Component Reaction of Carbon Dioxide, Propargylic Alcohols and Nucleophiles, Acta Phys. -Chim. Sin.2018, 34, 838-844. [link]

Abstract: Transformation of carbon dioxide into valuable organic molecules has attracted considerable attention over the past decades. In this regard, three-component reaction of CO2, propargylic alcohols and nucleophiles including amines, water and alcohols to prepare useful carbonyl compounds, for instance, carbamates, oxazolidinones, α-hydroxyl ketones and organic carbonates, is particularly appealing due to advantages of step and atom economy. CO2 is of thermodynamic stability and kinetic inertness, leading to the reactions involving CO2 are commonly thermodynamically unfavorable. We have developed an efficient three-component reaction of CO2, propargylic alcohols and nucleophiles to offer thermodynamically favorable ways for converting CO2 into cyclic carbonates and 2-oxazolidinones with vicinal diols or 2-aminoethanols. This review aims to summarize and discuss recent advances on three-component reaction of CO2, propargylic alcohols with nucleophiles to prepare various carbonyl compounds promoted by both metal catalysts and organocatalysts.

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  1. 刘晓放,何良年,二氧化碳的高值化利用,科学, 2018, 70, 14-19.
  1. Xue-Dong Li, Yu Cao, Ran Ma,Liang-Nian He*, Thermodynamically favorable protocol for the synthesis of 2-oxazolidinones via Cu(I)-catalyzed three-component reaction of propargylic alcohols, CO2 and 2-aminoethanols, J. CO2 Util., 2018, 25, 338-345. [link]

Abstract: Efficient CuI/1,10-phen-catalyzed three-component cascade reaction of propargylic alcohols, CO2, and 2-aminoethanols has been firstly developed for the thermodynamically favourable preparation of 2-oxazolidinones. In the presence of commercially available CuI, 1,10-phen (1,10-phenanthroline) and t-BuOK, the cascade reaction afforded the desired products in good to excellent yields with a broad substrate scope (14 examples). The predicted copper complex Cu2I2(phen)2 in situ formed from CuI and 1,10-phen could activate the triple bond through coordination. The isolation of α-alkylidene cyclic carbonate as the reaction intermediate suggests that the carboxylative cyclization of propargylic alcohol with CO2, followed by ring-opening reaction, is involved in the one-pot three-component cascade reaction.

  1. Yu Cao, Ran Ma, Ning Wang, Mei-Yan Wang, Xue-Dong Li, Liang-Nian He*, Selective hydrodeoxygenation of β-O-4 model compounds and aromatic ketones promoted by palladium chloride with acidic CO2/MeOH system, J. CO2 Util., 2018, 24, 328-333. [link]

Abstract: Selective hydrogenolysis is a crucial challenge for lignin valorization. A PdCl2-catalyzed hydrogenolysis of C-OH bond of various lignin β-O-4 alcohol model compounds was developed for preparation of corresponding phenethoxybenzene in 78-98% isolated yield. Notably, the introduction of low-pressure CO2 (1 MPa) remarkably improves the reaction efficiency and selectivity of phenethoxybenzene. Neither over-reduction of aromatic ring nor further debenzylation was detected. This is understandable that the in situ methylcarbonic acid generated from CO2 and methanol acts as an acidic catalyst and enhances the leaving ability of hydroxyl group of β-O-4 alcohols. Besides, the present PdCl2/CO2/MeOH catalyst system proved to be effective for reductive cleavage of C-O bonds of β-O-4 ketones, producing ethylbenzenes accompanied with phenols in high yields. Furthermore, this protocol could also be extended to selective hydrodeoxygenation of the carbonyl group to methylene in aromatic ketones. As a sound reaction medium, such in situ CO2/MeOH acidic system could be inherently neutralized by depressurizing CO2, providing feature advantages for simple post-processing and none waste disposal.

  1. Yu Cao, Xing He, Ning Wang, Hong-Ru Li,and Liang-Nian He*, Photochemical and Electrochemical Carbon Dioxide Utilization with Organic Compounds, Chin. J. Chem.2018, 36, 644-659. [link]

Abstract: In the last few years, photochemical and electrochemical CO2 transformations have attracted increasing attention in response to topical interest in renewable energy and green chemistry. The present minireview offers an overview about the current approaches for the photochemical and electrochemical carbon dioxide fixation with organic compounds. Valuable products, including carboxylic acids and heterocyclic compounds, are accessible through carboxylation and carboxylative cyclization, respectively. In photochemical and electrochemical processes, photo- or electro-induced radical ions or other high-energy organic compounds are considered as key intermediates to react with CO2. Besides, activation of CO2 to produce radical anions has also been reported.

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  1. Mei-Yan Wang, Xiao-Ya Li andLiang-Nian He*, Green Chemistry Education and Activity in China, Current Opinion in Green & Sustainable Chem., 2018, 13, 123-129. [link]

Abstract: With the increase of global environmental pollution, green chemistry has been an inevitable trend in the development of chemistry and chemical engineering, thus attracting much attention from the academia to industry and to governments. As a response to the “green challenge”, the so-called green chemistry movement has spread all over the world. In this perspective, we would like to present main programs associated with green chemistry in China, with a focus on green chemistry education and related activities.

  1. Chang Qiao, Xiang-Yang Yao, Xiao-Fang Liu, Hong-Ru Li*,Liang-Nian He*, Efficient Iron-Catalyzed Reductive N-Alkylation of Aromatic Amines with Carboxylic Acid and Hydrosilane, Asian J. Org. Chem.2018, 7, 1815-1818. [link]

Abstract: Development of efficient catalysis for the alkylation of amines with carboxylic acid is attracting much attention. Herein, we would like to report an earth‐abundant iron‐catalyzed protocol for N‐alkylation of amines using carboxylic acid as alkyl source and phenylsilane as reducing agent. With Fe2(CO)9 as a catalyst, a broad range of primary and secondary amines are successfully converted to the corresponding tertiary amines. Furthermore, this N‐alkylation mainly goes through the amide pathway; while the aldehyde pathway can not be ruled out.

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  1. Chang Qiao, Xiao-Fang Liu, Hong-Chen Fu, Hao-Peng Yang, Zhi-Bo Zhang,Liang-Nian He*, Directly Bridging Indoles to 3,3’-Bisindolylmethanes Using Carboxylic Acids and Hydrosilanes under Mild Conditions, Chem. Asian J.2018, 2664-2670. [link]

Abstract: A straightforward Lewis acid‐promoted protocol for 3,3′‐bisindolylmethanes (BIMs) synthesis by reductive alkylation of indoles at the C3 position with carboxylic acids in the presence of hydrosilane was developed for the first time. Instead of aldehydes, more readily available, stable, and easy‐to‐handle carboxylic acids have been employed as alternative alkylating agents. As an efficient organocatalyst, B(C6F5)3 enables the reductive alkylation of various substituted indole derivatives with carboxylic acids with up to 98 % yield at room temperature and under neat conditions. This metal‐free strategy offers an alternative approach for the direct functionalization of indoles to BIMs with carboxylic acids and such protocol allows selective reduction of carboxylic acid to aldehyde in combination with C−C bond formation.

  1. Xing He,  Yu Cao, Xian‐Dong Lang, Ning Wang,Liang‐Nian He*, Integrative Photoreduction of CO2with Subsequent Carbonylation: Photocatalysis for Reductive Functionalization of CO2ChemSusChem2018, 11, 3382-3387.[link]

Abstract: Efficient conversion of COinto fuels and chemicals with solar energy would be promising, but also faces great challenge. In this context, we describe the photoreductive functionalization of COto construct new C−C, C−N, and C−O bonds through the respective Pd‐catalyzed Suzuki carbonylation, aminocarbonylation, and alkoxycarbonylation of aryl iodides with CO in situ generated through the photoreduction of CO2. This protocol opens up an alternative avenue for COutilization by harnessing solar energy.

  1. Xue-Dong Li#, Shu-Mei Xia#, Kai-Hong Chen, Xiao-Fang Liu, Hong-Ru Li* andLiang-Nian He*,Copper catalysis: ligand-controlled selective N-methylation or N-formylation of amines with CO2 and phenylsilane. Green Chem., 2018, 20(21), 4853-4858. [link]

Abstract: Cupric subcarbonate (Cu2(OH)2CO3) was found to be effective for the reductive functionalization of CO2 to produce formamides and methylamines with phenylsilane as reductant. Interestingly, N-formylation and N-methylation were switched on/off by subtly choosing the ligand: DPPB (1,4-bis(diphenylphosphino)butane) promoted N-methylation whereas Ph2CyP (diphenylcyclohexylphosphine) favored for N-formylation.

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  1. Yu Cao, Ning Wang, Xing He, Hong-Ru Li* andLiang-Nian He*, Photocatalytic Oxidation and Subsequent Hydrogenolysis of Lignin β-O-4 Models to Aromatics Promoted by In Situ Carbonic Acid, ACS Sustain. Chem. Eng., 2018, 6(11), 15032-15039. [link]

Abstract: The cleavage of C–O bond in lignin β-O-4 model compounds to form aromatics has been achieved via a two-step process, comprising visible-light photocatalytic oxidation and in situ carbonic acid-facilitated hydrogenolysis. In the first step, with readily available persulfate as radical initiator and cheap copper as catalyst, the secondary alcohol in the β-O-4 alkyl-aryl ether linkage is selectively oxidized to the corresponding ketone in up to 99% yield under visible-light irradiation. The second step features the C–O bond cleavage of lignin β-O-4 ketones promoted by in situ acidic EtOH/H2O/CO2 system in the presence of zinc powder, producing acetophenones and phenols in high yield. This protocol provides a novel alternative to selective fragmentation of β-O-4 linkage to aromatic monomers under mild reaction conditions.

  1. Shumei Xia, Yu Song, Xuedong Li, Hongru Li* and Liang-Nian He*Ionic Liquid-Promoted Three-Component Domino Reaction of Propargyl Alcohols, Carbon Dioxide and 2-Aminoethanols: A Thermodynamically Favorable Synthesis of 2-Oxazolidinones. Molecules2018, 23(11), 3033.  [link]

Abstract: To circumvent the thermodynamic limitation of the synthesis of oxazolidinones starting from 2-aminoethanols and CO2 and realize incorporation CO2 under atmospheric pressure, a protic ionic liquid-facilitated three-component reaction of propargyl alcohols, CO2 and 2-aminoethanols was developed to produce 2-oxazolidinones along with equal amount of α-hydroxyl ketones. The ionic liquid structure, reaction temperature and reaction time were in detail investigated. And 15 mol% 1,5,7-triazabicylo[4.4.0]dec-5-ene ([TBDH][TFE]) trifluoroethanol was found to be able to synergistically activate the substrate and CO2, thus catalyzing this cascade reaction under atmospheric CO2 pressure. By employing this task-specific ionic liquid as sustainable catalyst, 2-aminoethanols with different substituents were successfully transformed to 2-oxazolidinones with moderate to excellent yield after 12 h at 80 °C.

  1. Shu-Mei Xia, Kai-Hong Chen, Hong-Chen Fu andLiang-Nian He*, Ionic Liquids Catalysis for Carbon Dioxide Conversion With Nucleophiles. Front. Chem.2018, 6: 462. DOI: 10.3389/fchem.2018.00462. [link]

Abstract: Carbon dioxide, as a promising C1 synthon, has attracted great interest in organic synthesis. Due to the thermodynamic stability and kinetic inertness of CO2, developing efficient strategies for CO2 activation and subsequent conversion is very crucial. In this context, Ionic liquids (ILs) show great potential for capturing and activating CO2 owing to their unique structures and properties, making them become ideal alternatives to volatile organic solvents and/or catalysts for CO2 transformation. This minireview aims at summarizing ILs-promoted reactions of CO2 with N-nucleophiles (primary amines)/O-nucleophiles (primary alcohols, water). Two catalytic systems i.e., metal/ILs binary systems such as Cu/ILs systems and Ag/ILs systems as well as single ILs systems including anion-functionalized ILs and bifunctionalized ILs have been developed for CO2 catalytic conversion, for instance, carboxylative cyclization of nucleophiles e.g., propargylic alcohols, amines, 2-aminobenzonitriles and o-aminobenzenethiol, and formylation of amines or 2-aminothiophenols with hydrosilanes to afford various value-added chemicals e.g., cyclic carbamates, unsymmetrical organic carbonates, α-hydroxyl ketones, and benzimidazolones. In a word, IL could provide a powerful tool for efficient CO2 utilization.

  1. Xiao-Fang Liu, Xiao-Ya Li, Chang Qiao, Hong-Chen Fu, Liang-Nian He*, Betaine Catalysis for Hierarchical Reduction of CO2 with Amine and Hydrosilane to Formamide, Aminal and Methylamine, Angew. Chem. Int. Ed.2017, 56, 7425-7429. [link]

Abstract: An efficient, sustainable organocatalyst e.g. glycine betaine was developed for reductive functionalization of CO2 with amines and diphenylsilane. Methylamines and formamides could respectively be obtained with high yield via tuning CO2 pressure and reaction temperature. Betaine catalysis was efficient for the formation of formamide at 10 bar CO2, 50 oC. Exclusively yielding methylamines from various amines with atmospheric pressure of CO2 was attained at 70 oC. Based on identification of the key intermediate i.e. aminal, an alternative mechanism for methylation involving the C0 silyl acetal and aminal was proposed. Furthermore, reducing CO2 amount to approx. 1 equiv. afforded aminal with high yield and selectivity. Therefore, betaine catalysis in this study afforded the products with diversified energy content i.e. formamide, aminal and methylamine respectively through hierarchical 2-, 4- and 6-electron reduction of CO2 coupled with C-N bond formation for the first time.

  1. Xi Liu, Mei-Yan Wang, Si-Yuan Wang, Qi Wang,Liang-Nian He*, Zinc(II) Catalyst In Situ Formed for Incorporation of CO2 into 2-Oxazolidinones with Propargylic Amines at Atmospheric Pressure, ChemSusChem, 2017, 10, 1210-1216. [link]

Abstract: Incorporation of CO2 into heterocyclic compounds (i.e., 2-oxazolidinones) under mild conditions, especially at atmospheric pressure still remains challenging. The mononuclear ZnII complex ZnCl2(TBD)2, where TBD=1,5,7-triazabicyclo[4.4.0]dec-5-ene, in this study was demonstrated as a robust catalyst for the carboxylative cyclization of propargylic amines with CO2 to exclusively afford various 2-oxazolidinones in excellent yields. Notably, the ZnII catalytic species is readily generated in situ from ZnCl2 and TBD without pre-preparation and further isolation. Such a CO2 fixation protocol could proceed smoothly under atmospheric pressure at mild temperature in an atom economic and environmentally benign manner. 13C NMR and control experiments were performed to explore the possible interaction between ZnII and the carbon–carbon triple bond of propargylic amine. The dual catalytic role of the Zn catalyst to enhance O-nucleophilicity of the carbamate anion intermediate and activate the carbon–carbon triple bond is proposed based on mechanistic investigations.

  1. Mei-Yan Wang, Yu Cao, Xi Liu, Ning Wang, Liang-Nian He* and Si-Han Li, Photoinduced radical-initiated carboxylative cyclization of allyl amines with carbon dioxide. Green Chem.2017, 19, 1240-1244. [link]

Abstract: Visible light-promoted CO2 upgrading: a highly efficient and metal-free photochemical method for the carboxylative cyclization of allyl amines with CO2 is reported to prepare perfluoroalkylated oxazolidinones with high efficiency under ambient conditions by using perfluoroalkyl iodides as radical sources.

  1. Zhi-Hua Zhou, Qing-Wen Song, and Liang-Nian He*, Silver(I)-Promoted Cascade Reaction of Propargylic Alcohols, Carbon Dioxide, and Vicinal Diols: Thermodynamically Favorable Route to Cyclic Carbonates, ACS Omega2017, 2, 337-345. [link]

Abstract: A silver(I)-promoted cascade reaction was developed for the synthesis of cyclic carbonates from terminal propargylic alcohols, carbon dioxide, and vicinal diols. Compared with direct condensation of vicinal diols with CO2, this protocol provides a thermodynamically favorable route to cyclic carbonates and α-hydroxyl ketones in excellent yields (up to 97%) without the additional dehydration step. Such a cascade procedure proceeds presumably through initial reaction of propargylic alcohol with CO2 and subsequent nucleophilic attack of vicinal alcohol on in situ-formed α-alkylidene cyclic carbonate, resulting in successive generation of α-alkylidene cyclic carbonate, unsymmetrical β-oxoalkyl carbonate, cyclic carbonate, and α-hydroxyl ketone.

  1. Xi Liu, Liang-Nian He*, Synthesis of Lactones and Other Heterocycles in Topical Collection “Chemical Transformations of Carbon Dioxide”; Series Editors: Xiao-Feng Wu, Matthias Beller. Topics in Current Chemistry (ISSN: 2365-0869 (Print) 2364-8961 (Online)), Springer International Publishing. (2017) 375: 21. [link]

Abstract: Chemical fixation of CO2 into value-added chemicals represents a promising field in view of sustainable development and green synthesis. In this aspect, the construction of heterocyclic compounds from CO2 and readily available starting materials is particularly appealing in both organic and pharmaceutical fields since CO2 can be regarded as carbon and oxygen resource with advantages of abundance, renewability, non-toxicity, and non-flammability. In this chapter, we have summarized elegant protocols with elaborately designed substrates for the direct incorporation of entire CO2 molecule or “CO” or “C” fragments into lactones and other heterocycles such as oxazolidinones, cyclic carbonates, quinazoline-2,4(1H,3H)-diones, etc., through the formation of carbon–carbon, carbon–nitrogen and/or carbon–oxygen bonds promoted by homogeneous catalysts.

  1. Xuedong Li, Xing He, Xiaofang Liu, Liang-Nian He*, Ruthenium-promoted reductive transformation of CO2Sci China Chem2017, 60, 841-852. [link]

Abstract: The reductive transformation of CO2 to energy related products including formic acid, CO, formamide, methanol and methylamine could be a promising option to supply renewable energy. In this aspect, ruthenium has found wide application in hydrogenation of various carbonyl groups, and has successfully been applied to reductive transformation of CO2 with high catalytic efficiency and excellent selectivity. In addition, ruthenium complexes have also served as effective photosensitizers for COphotoreduction. Classified by reductive products, this review summarizes and updates advances on the Ru-catalyzed reduction of CO2 along with catalyst development on the basis of mechanistic understanding at a molecular level.

  1. Xiao-Fang Liu, Mei-Yan Wang and Liang-Nian He*, Heterogeneous Catalysis for Oxazolidinone Synthesis from Aziridines and CO2Current Organic Chemistry2017, 21, 698-707. [link]

Abstract: With the increasing environmental and societal concerns about global warming associated with carbon emission, great efforts have been devoted to carbon dioxide fixation during the past two decades. Indeed, CO2 has been widely used as a potential C1 building block for the production of various chemical products, as it is nontoxic, renewable, economical and abundant. One promising methodology is the coupling reaction of CO2 with aziridines to afford oxazolidinones, which is 100% atom-efficient and eco-friendly. In addition, oxazolidinones are important heterocyclic compounds showing application as intermediates and chiral auxiliaries in organic synthesis. To date, numerous homogeneous catalysts have been developed for this reaction. With criteria of green chemistry and sustainable development, developing efficient heterogeneous catalysts would be crucial for industrial application. In this review article, we present the latest progress on the coupling reaction of CO2 with aziridines, and particularly focus on the preparation, activity evaluation and recyclability of various heterogeneous catalytic systems including mesoporous material, functionalized polymer-based catalysts and supported catalysts. We hope this review could stimulate further research on oxazolidinone synthesis from CO2 and aziridines with green and efficient heterogeneous catalyst.

  1. Editorial Overview:Liangnian He, Thibault Cantat, Innovative methods in CO2 conversion: A breath of fresh air? Current Opinion in Green and Sustainable Chemistry2017, DOI: 10.1016/j.cogsc.2017.01.001. [link]
  1. Liang-Nian He (Editor-in-Chief), Preface for Current Organic Synthesis2017, 14(1), 2. [link]
  1. Chang Qiao, Xiao-Fang Liu, Xi Liu, andLiang-Nian He*, Copper(II)-Catalyzed Selective Reductive Methylation of Amines with Formic Acid: An Option for Indirect Utilization of CO2Org. Lett.2017, 19, 1490-1493. [link]

Abstract: A copper-catalyzed protocol for reductive methylation of amines and imine with formic acid as a C1 source and phenylsilane as a reductant is reported for the first time, affording the corresponding methylamines in good to excellent yields under mild conditions. This protocol offers an alternative method for indirect utilization of CO2, as formic acid can be readily obtained from hydrogenation of CO2.

  1. Ran Ma,Liang-Nian He*,Xiao-Fang Liu, Xi Liu and Mei-Yan Wang, DBU as activator for the N-iodosuccinimide promoted chemical fixation of carbon dioxide with epoxides. J. CO2 Util., 2017, 19, 28-32. [link]

Abstract: The combination of N-Iodosuccinimide (NIS) and DBU is developed as an efficient organocatalyst system for the cycloaddition of carbon dioxide (CO2) at atmospheric pressure with epoxides without utilization of additional solvents, forming cyclic carbonates in high yields with a broad substrate scope. DBU functions as a nucleophilic promoter for the activation of NIS to be a more electrophilic iodine species thus being capable of activating the epoxides. On the other hand, NIS also provides a nucleophilic nitrogen species, i.e. succinimide anion for ring-opening of the epoxide.

  1. Xiao-Fang Liu,Chang Qiao, Xiao-Ya Li and Liang-Nian He*, Carboxylate-promoted reductive functionalization of CO2 with amines and hydrosilanes under mild conditions, Green Chem., 2017, 19, 1726-1731. [link]

Abstract: Various oxygen-nucleophiles especially carboxylates, e.g. cesium/tetrabutylammonium carboxylate, were proved to be efficient and selective catalysts for reductive functionalization of CO2 with amines and hydrosilanes to methylamines. Various amines including aromatic and aliphatic, primary and secondary ones were methylated successfully in the presence of diphenylsilane as the reductant under 50 °C and an atmospheric pressure of CO2. Furthermore, a reaction pathway involving CO2 reduction to the C0 species i.e. aminal rather than the formamide as the intermediate was proposed. This protocol represents a transition metal-free and environmentally friendly option for CO2 conversion to useful chemicals via the formation of C–N bonds coupled with six-electron reduction of CO2 to the methanol level under mild conditions.

  1. Qing-Wen Song, Zhi-Hua Zhou and Liang-Nian He*, Efficient, selective and sustainable catalysis of carbon dioxide, Green Chem.2017, 19, 3707-3728. [link]

Abstract: Performing CO2 conversion in a cost-effective and environmentally benign manner would be promising and remains still challenging due to its thermodynamic stability and kinetic inertness. Herein, we would like to update significant advances in organic synthesis using CO2 with high catalytic efficiency and excellent selectivity towards the target product mainly during latest five years (2012-2016). Achieving an efficient and selective CO2 conversion depends on development of metal catalysts (especially functional metal complex catalysis) including main-group metal, typical transition metal and lanthanide series metal as well as organocatalysts e.g. N-heterocyclic carbene, N-heterocyclic olefin, task-specific ionic liquid, superbase and frustrated Lewis pair being able to effectively activate CO2 and/or the substrate on the basis of mechanistic understanding at a molecular level. This review just covers typical catalytic transformation of CO2, for instance, carboxylation, amidation, hydrogenation, and representative green processes like solvent-less, halogen-free that use CO2 as an ideal carbon-neutral source to prepare valuable compounds with the improved atom economy and enhanced sustainability of chemical processes through green catalysis. In particular, in situ catalytic CO2 conversion, i.e. the combination of carbon capture and subsequent conversion, a recent breakthrough in CO2 chemistry field is also discussed.

  1. Gang Xiong, Bing Yu, Jie Dong, Ying Shi, Bin Zhao* and Liang-Nian He*, Cluster-based MOFs with Accelerating Chemical Conversion of CO2 through C-C Bond Formation, Chem. Commun.2017, 53, 6013-6016. [link]

Abstract: Investigations on metal-organic frameworks (MOFs) as direct catalysts have been well documented, but it has never been reported that MOFs directly catalyze the chemical conversion of terminal alkynes and CO2 as chemical feedstock into valuable chemical products. We report here two cluster-based MOFs I and II assembled by multinuclear Gd-cluster and Cu-cluster, displaying high thermal and solvent stabilities. I and II as heterogeneous catalysts possess active catalytic centers [Cu12I12] and [Cu3I2], respectively, exhibiting excellent catalytic performance in the carboxylation reactions of CO2 and 14 kinds of terminal alkynes under 1 atm and mild conditions. This is the first time for MOFs materials to catalyze the carboxylation reaction of terminal alkynes and CO2 without any cocatalyst/additive. This work not only reduces greenhouse gas emission but also provides high valuable materials, opening a wide space in seeking recoverable catalysts to accelerate chemical conversion of CO2.

  1. Xue-Dong Li, Qing-Wen Song, Xian-Dong Lang,Liang-Nian He*, Yao Chang, Ag(I)/TMG-Promoted Cascade Reaction of Propargyl Alcohols, Carbon Dioxide, and 2-Aminoethanols to 2-Oxazolidinones, ChemPhysChem2017, 18, 3182-3188. [link]

Abstract: Chemical valorization of CO2 to access various value-added compounds has been a long-term and challenging object from the viewpoint of sustainable chemistry. Herein, a one-pot three-component reaction of terminal propargyl alcohols, CO2, and 2-aminoethanols was developed for the synthesis of 2-oxazolidinones and equal amount of α-hydroxyl ketones promoted by Ag2O/TMG (1,1,3,3-tetramethylguanidine) with the TON (turnover number) up to 1260. By addition of terminal propargyl alcohol, thermodynamic disadvantage of the conventional 2-aminoethanol/CO2 coupling was ameliorated. Mechanistic investigations including control experiments, kinetic and NMR studies suggest that the reaction proceeds through a cascade pathway and TMG could activate propargyl alcohol and 2-aminoethanol through the formation of hydrogen bonding and also activate CO2.

  1. Xian-Dong Lang, Xing He, Zheng-Ming Li* and Liang-Nian He*, New routes for CO2 activation and subsequent conversion, Current Opinion in Green and Sustainable Chemistry2017, 7, 31-38. [link]

Abstract: Nowadays, transformation of CO2 into value-added chemicals and fuels has attracted much attention. However, the inherent thermodynamic and kinetic limitation of COrepresents the biggest obstacle associated with CO2 conversion. In this context, activation of CO2 would be prerequisite for its conversion. In this minireview, we would like to provide a concise overview of recent advances on CO2 activation by various organocatalysts including N-heterocyclic carbenes (NHCs)/N-heterocyclicolefins (NHOs), phosphorus ylides, polyoxometalates (POMs), ionic liquids (ILs), frustrated Lewis pairs (FLPs), superbases. In addition, carbon capture and utilization (CCU) strategy, the elegant combination of carbon capture and subsequent conversion, has also been summarized, which is designed to obviate the high energy input associated with carbon capture and storage/sequestration (CCS) process. In order to demonstrate the efficiency of CO2 activation, application of abovementioned COactivation in the synthesis of cyclic carbonates, carbon monoxide, quinazoline-2,4(1H,3H)-diones, methanol, oxazolidinones, formamides, ureas, alkyl 2-alkynoates, α-hydroxy ketones, and formic acid are also included.

  1. Ke Shi, Liefeng Feng,Liang-Nian He, Hongru Li*, Solubility Determination and Correlation of Gatifloxacin, Enrofloxacin, and Ciprofloxacin in Supercritical CO2J. Chem. & Eng. Data, 2017, 62, 4235-4243.
  1. Ke Shi, Liefeng Feng,Liang-Nian He, Hongru Li*, Thermodynamic modeling of the supercritical CO2 impregnation process for the preparation ibuprofen/polymethylmethacrylate composite, J. Taiwan Inst. Chem. Eng.2017, 78, 471-476.
  1. Zhi-Hua Zhou, Chun-Xiang Guo, Jia-Ning Xie, Kai-Xuan Liu, andLiang-Nian He*, Silver Chloride/Triphenylphosphine-Promoted Carboxylation of Arylboronic Esters with Carbon Dioxide at Atmospheric Pressure, Current Org. Synth., 2017, 14, 1185-1192. [link]

Abstract: The carboxylation of arylboronic esters with ambient CO2 was achieved based on silver chloride/triphenylphosphine system. To achieve this transformation under atmospheric CO2 pressure, the effect of base and solvent was investigated and cesium carbonate and dimethyl sulfoxide were confirmed as the most appropriate base and solvent. Through this protocol, various functionalized carboxylic acids were synthesized in 85-99% yields. In addition, C-13 isotope labeling experiment confirmed the exclusive carboxyl source from CO2 rather than cesium carbonate.

  1. Xing He, Xiao-Ya Li, Yu Song, Shu-Mei Xia, Xian-Dong Lang and Liang-Nian He*, Synthesis of Urea Derivatives Using Carbon Dioxide as Carbonylation Reagent in Ionic Liquids, Current Organocatal., 2017, 4 (2), 112-121. [link]

Abstract: Urea and its derivatives, which are usually generated through the carbonylation reaction between amines and carbonylation reagent, have been found widespread applications in agriculture and pharmaceuticals. Among the carbonylation reaction, it is the most appealing and promising strategy that employing CO2 as a green carbonylation reagent. However, CO2 inherent thermodynamic stability and kinetic inertness limit its application. Apart from being regarded as one of green solvents, ionic liquid is also an efficient organocatalyst for COcapture or activation due to the interaction between CO2 with cation or anion of ionic liquid. In this minireview, we have summarized representative synthetic methodologies of urea derivatives using carbon dioxide as a green carbonylation reagent and using ionic liquids as solvents and/or organocatalysts.

  1. Qing-Wen Song andLiang-Nian He*, Robust Silver(I) Catalyst for the Carboxylative Cyclization of Propargylic Alcohols with Carbon Dioxide under Ambient Conditions, Adv. Synth. Catal.2016, 358(8), 1251-1258. [Selected as VIP Paper]. [link]

Abstract: Inspired by the bulkier bis(triphenylphosphine)–silver cation-induced mechanism of propargylic alcohols and carbon dioxide through the alkyl carbonate intermediate, a robust dual-component catalytic system consisting of silver acetate and tetraheptylammonium bromide was rationally developed for the synthesis of α-methylene cyclic carbonates under ambient conditions without employing any additional organic base and ligand. This is one of the most effective catalysts reported to date for this conversion, with a very high turnover number of up to 6024, probably due to the synergistic effect of Lewis basic and Lewis acidic species for the activation of both propargylic alcohol and carbon dioxide by the formation of the alkyl carbonate with a bulkier counterion. Notably, this catalyst also worked well for the carboxylative cyclization of propargylic amines with carbon dioxide with the highest turnover number of 544.

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  1. Ran Ma, Liang-Nian He* and Yue-Biao Zhou, An efficient and recyclable tetraoxo-coordinated zinc catalyst for the cycloaddition of epoxides with carbon dioxide at atmospheric pressure, Green Chem.2016, 18(1), 226-231. [link]

Abstract: An efficient and recyclable catalytic system of a Zn(O)4-coordinated complex e.g. 2-hydroxypyridine N-oxide zinc(II), Zn(OPO)2 and tetrabutylammonium iodide (TBAI) was developed for the cyclic carbonate synthesis from epoxides and CO2 without the use of any organic solvents. This easily prepared, low-toxic Zn(OPO)2 may have a strong Lewis acidity for the activation of epoxides and exhibited high activity (TOF up to 22000 h1) even at a CO2 pressure as low as 1 bar with a broad substrate scope. Furthermore, the catalyst can be easily recovered and reused five times without a significant loss of its catalytic activity.

  1. Mei-Yan Wang, Qing-Wen Song, Ran Ma, Jia-Ning Xie andLiang-Nian He*, Efficient conversion of carbon dioxide at atmospheric pressure to 2-oxazolidinones promoted by bifunctional Cu(II)-substituted polyoxometalate-based ionic liquids, Green Chem., 2016, 18(1), 226-231. [link]

Abstract: Copper(II) substituted polyoxometalate-based ionic liquids e.g. [(nC7H15)4N]6[α-SiW11O39Cu] were successfully developed as halogen-free bifunctional catalysts for the carboxylative cyclization of propargylic amines with CO2. Such a CO2 fixation protocol proceeded smoothly at atmospheric pressure under solvent-free conditions, in an environmentally benign and low energy-input manner. Notably, various propargylic amines could react smoothly to afford 2-oxazolidinones as the target products in high to quantitative yields. Furthermore, the dual activation of both propargylic amine and CO2 by [(nC7H15)4N]6[α-SiW11O39Cu] was studied using NMR techniques and control experiments.

  1. Ran Ma, Liang-Nian He,* An-Hua Liu and Qing-Wen Song, Cu(II)-catalyzed esterification reaction via aerobic oxidative cleavage of C(CO)–C(alkyl) bonds, Chem. Commun.2016, 52, 2145-2148. [link]

Abstract: A novel Cu(II)-catalyzed aerobic oxidative esterification of simple ketones for the synthesis of esters has been developed with wide functional group tolerance. This process is assumed to go through a tandem sequence consisting of α-oxygenation/esterification/nucleophilic addition/C–C bond cleavage and carbon dioxide is released as the only byproduct.

  1. Shuai Zhang, Ran Ma, Liang-Nian He*, Transition Metal-Free Incorporation of CO2 in Carbon Dioxide and Organometallics, Vol. 53, Springer International Publishing, 2016, pp. 143-169. [link]

Abstract: Carbon dioxide can be regarded as an ideal C1 chemical feedstock in both academic and pharmaceutical laboratories owing to its abundance, low cost, non-toxicity, and nonflammability. However, due to CO2 inherent thermodynamic stability and kinetic inertness, it is difficult to convert CO2 to value-added chemicals under mild conditions. In order to overcome such barriers, numerous useful synthetic methodologies by strategically using highly active catalysts have been developed for the incorporation of CO2 to organic compounds. Transition metal-free compounds are proved to be promising efficacious catalysts able to activate CO2 molecule for efficient transformation of CO2 on the basis of mechanistic understanding at the molecular level. This chapter features recent advances at methodologies for catalytic transformation of CO2 promoted by organocatalysts (e.g., N-heterocyclic carbenes, frustrated Lewis pairs and superbases), ionic liquids, and main group metal to produce value-added chemicals such as linear or cyclic carbonates, quinazoline-2,4(1H,3H)-diones, alkylidene cyclic carbonates, amino acids, and so on.

  1. Mei-Yan Wang, Ran Ma, Liang-Nian He*, Polyoxometalate-based ionic liquids-promoted CO2 conversion, Science China Chemistry2016, 59, 507-516. [link]

Abstract: Polyoxometalates(POMs) are a class of molecular metal oxides, showing numerous applications in various chemical processes due to their unique acid/base and redox features. By adjusting the tunable molecular structures of the anions and counter cations, plenty of POM-based ionic liquids(POM-based ILs) have been fabricated to be used in various fields, such as catalysis, structural chemistry and material science. As a class of excellent catalysts, POM-based ILs have shown advantages in the emerging field of CO2 utilization such as CO2 capture, cycloaddition of CO2 to epoxides, and reduction of CO2, owing to the efficient activation of CO2 by POM anions. This review summarizes recent advances in the catalysis of POM-based ILs, and particularly highlights the areas that are related to CO2 conversion.

  1. Xiao-Fang Liu, Qing-Wen Song, Shuai Zhang, Liang-Nian He*, Hydrogen bonding-inspired organocatalysts for COfixation with epoxides to cyclic carbonates, Catal. Today2016, 263, 69-74. [link]

Abstract: Carboxyl-containing organocatalysts, e.g. EDTA (ethylenediaminetetraacetic acid) in combination with nucleophilic halide such as nBu4NBr were demonstrated to be efficient catalyst systems for the synthesis of cyclic carbonates from CO2 and a broad range of epoxides in excellent yield and selectivity. Thanks to synergistic effects of carboxylic groups and bromide anion, the cycloaddition reaction proceeded smoothly at 5 bar CO2 under mild reaction conditions. Interaction of carboxylic groups in EDTA with the epoxide via hydrogen bonding presumably facilitates the ring-opening of the epoxide by the nucleophile e.g. bromide. In particular, multiple carboxylic groups in one molecule i.e. EDTA could more effectively activate the epoxide and stabilize the alkoxide intermediate through multi-site hydrogen bonding in comparison with monocarboxylic acid. Moreover, the carboxylic acid like EDTA used in this study represents a cheap, commercially available, environmentally benign, metal-free catalyst for CO2 conversion. Thus, this catalytic protocol could have potential application for catalytic fixation of CO2 into value-added chemicals.

  1. Zhang Shuai, Li Xuedong,He Liang-Nian*, Reductive Carboxylation of Unsaturated Hydrocarbons with Carbon Dioxide. Acta Chim. Sinica2016, 74(1): 17-23. [link]

Abstract: Transition metal-catalyzed reductive carboxylation of unsaturated hydrocarbons with CO2 is a promising and potential strategy, offering an excellent alternative access to carboxylic acids/acrylic acids. The active transition metal species could react with unsaturated hydrocarbons and CO2 to generate the stable metallalactones or carboxylic salts. The transmetalation between reductants and metallalactones/carboxylic salts regenerates the active catalytic species. As a result, the reductive carboxylation is able to run in a catalytic mode rather than stoichiometric version. Organometal species, silanes/boranes, metal powder, methanol and hydrogens have been developed as reducing reagents in reductive carboxylation with CO2. In this perspective, the latest advances on the transition metal-catalyzed reductive carboxylation are summarized, with particular focus on the application of reductants and related reaction mechanism at a molecular level.

  1. Xi Liu, Shuai Zhang, Qing-Wen Song, Xiao-Fang Liu, Ran Ma and Liang-Nian He*. Cooperative calcium-based catalysis with 1,8-diazabicyclo[5.4.0]-undec-7-ene for the cycloaddition of epoxides with CO2 at atmospheric pressure, Green Chem.2016, 18, 2871-2876. [link]

Abstract: A dual activation catalytic system consisting of CaBr2 and 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) was developed for efficient fixation of CO2 with epoxides to cyclic carbonates. Such dual catalysis renders the reaction to perform smoothly at atmospheric CO2 pressure, presumably due to simultaneous activation of CO2 by DBU and epoxide by CaBr2. In addition, the activation role of CaBr2 was also studied by density functional theory (DFT) calculation. A plausible mechanism involving the DBU-COadduct assisted ring opening path and bromide anion-promoted ring opening path is proposed, in combination with the activation of epoxide by calcium cation. This process represents a simple, cost-effective and biocompatible route to cyclic carbonates from CO2 under mild condition, especially at atmospheric CO2 pressure.

  1. Ran Ma, Yue-Biao Zhou,Liang-Nian He*, Carbon dioxide promoted reductive amination of aldehydes in water mediated by iron powder and catalytic palladium on activated carbon, Catal. Today2016, 274, 35-39. [link]

Abstract: A mixture of iron powder and catalytic palladium on activated carbon has been developed for reductive amination of various aromatic aldehydes, including 2-pyridinecarboxaldehyde, in water under CO2 atmosphere. The reversible reaction of CO2 with water could form carbonic acid and hydrogen transfer from water to Pd(0) took place with the presence of iron powder, leading to formation of high-active Pd hydrides for the reductive amination process. On the other hand, the reaction system could be inherently neutralized by ready removal of CO2, thus resulting in facile post-processing.

  1. Xuedong Li, Xiandong Lang, Qingwen Song, Yakun Guo, Liang-Nian He*, Cu(I)-Catalyzed Three-component Reaction of Propargylic Alcohol, Secondary Amines and Atmospheric CO2Chin. J. Org. Chem2016, 36, 744-751. [link]

Abstract: β-Oxopropylcarbamates constitute an important kind of organic compounds, owing to the extensive applications in agrochemicals, pharmaceuticals, organic synthesis, and protection of amino group. In this article, an efficient and atom-economical Cu(I) catalyzed three-component reaction of propargylic alcohols, secondary amines and CO2 has been developed under atmospheric pressure, affording various β-oxopropylcarbamates in high yields with high selectivity by controlling the concentration of O2. This protocol avoids the use of high pressure of CO2 and provides an extremely simple way to access the synthetically useful β-oxopropylcarbamates.

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  1. Xian-Dong Lang, Yi-Chen Yu, Zheng-Ming Li, Liang-Nian He*, Protic ionic liquids-promoted efficient synthesis of quinazolines from 2-aminobenzonitriles and CO2 at ambient conditions, J. CO2 Util., 2016, 15, 115-122. [link]

Abstract: Despite recent renaissance of CO2 chemistry, transformation of CO2 at ambient conditions remains still of great challenge. In this work, an easily prepared protic ionic liquid e.g. 1,1,3,3-tetramethylguanidinium imidazolide [HTMG][Im] was developed as highly efficient, recyclable and bifunctional catalyst for the carboxylative cyclization of 2-aminobenzonitriles with CO2 at atmospheric pressure and room temperature. The catalytic protocol was found to be applicable to various 2-aminobenzonitriles bearing electron-withdrawing or electron-donating substituents, affording the corresponding quinazoline-2,4(1H,3H)-diones in moderate to excellent yields. In addition, the catalyst could be conveniently recovered and reused for five cycles with almost consistent activity. Consequently, this process represents an alternative approach for the efficient and greener chemical fixation of CO2 to afford valuable heterocycles.

  1. Zhen-Feng Diao, Zhi-Hua Zhou, Chun-Xiang Guo, Bing Yu andLiang-Nian He*, Propylene oxide as a dehydrating agent: potassium carbonate-catalyzed carboxylative cyclization of propylene glycol with CO2 in a polyethylene glycol/CO2 biphasic system, RSC Adv.2016, 6(38), 32400-32404. [link]

Abstract: The synthesis of propylene carbonate (PC) from 1,2-propylene glycol (PG) and CO2 was smoothly performed in a PEG800 (polyethylene glycol)/CO2 biphasic system with K2CO3 as a catalyst and propylene oxide (PO) as a dehydrating agent. In the reaction of PG with CO2, PO presumably removes the water produced, and simultaneously generates more PG, both of which shift the thermodynamic control process and thus accelerate the PC synthesis. The PC yield directly from PG and CO2 reached 78% under relatively mild reaction conditions (4 MPa, 120 °C, 10 h). Notably, no additional by-product was detected in this process, resulting in economic benefits and the ease of workup procedure.

  1. Xian-Dong Lang,Liang-Nian He*, Green Catalytic Process for Cyclic Carbonate Synthesis from Carbon Dioxide under Mild Conditions, Chem. Rec. 2016, 16, 1337-1352. [link]

Abstract: As a renewable and abundant C1 resource possessing multiple attractive characteristics, such as low cost, nontoxicity, non-flammability, and easy accessibility, CO2 conversion into value-added chemicals and fuels can contribute to green chemistry and sustainable development. Since CO2 is a thermodynamically inert molecule, the activation of CO2 is pivotal for its effective conversion. In this regard, the formation of a transition-metal CO2 complex through direct coordination is one of the most powerful ways to induce the inert CO2 molecule to undergo chemical reactions. To date, numerous processes have been developed for efficient synthesis of cyclic carbonates from CO2. On the basis of mechanistic understanding, we have developed efficient metal catalysts and green processes, including heterogeneous catalysis, and metal-free systems, such as ionic liquids, for cyclic carbonate synthesis. The big challenge is to develop catalysts that promote the reaction under low pressure (preferably at 1 bar). In this context, bifunctional catalysis is capable of synergistic activation of both the substrate and CO2 molecule, and thus, could render CO2 conversion smoothly under mild conditions. Alternatively, converting CO2 derivatives, that is, the captured CO2 as an activated species, would more easily take place at low pressure in comparison with gaseous CO2. The aim of this Personal Account is to summarize versatile catalytic processes for cyclic carbonate synthesis from CO2, including epoxide/CO2 coupling reaction, carboxylation of 1,2-diol with CO2, oxidative cyclization of olefins with CO2, condensation of vicinal halohydrin with CO2, carboxylative cyclization of propargyl alcohols with CO2, and conversion of the CO2 derivatives.

  1. Xian-Dong Lang,Yi-Chen Yu, Liang-Nian He*, Zn-salen complexes with multiple hydrogen bonding donor and protic ammonium bromide: bifunctional catalysts for CO2 fixation with epoxides at atmospheric pressure, J Mol Catal A: Chem. 2016, 420, 208-215. [link]

Abstract: Bifunctional Zn-salen complexes with multiple hydrogen bonding donors and protic ammonium bromides were developed as efficient catalysts for the formation of 4-phenyl-1,3-dioxolan-2-one from styrene oxide and CO2. Owing to synergistic effects of multiple sites on epoxide activation (Lewis acidic zinc, phenolic hydroxyl group and protonated tertiary ammonium able to activate epoxide and bromide anion acting as a nucleophile), the easily-synthesized Zn-salen complexes showed outstanding performance at mild reaction conditions (CO2 0.1 MPa, 100 °C) using only 0.3 mol% catalyst amount. Besides, this protocol is applicable to a variety of epoxides including internal epoxide, giving the corresponding cyclic carbonates in good to excellent yields. Notably, 200 mmol-scale experiment was successfully conducted and TON of 49288 ± 13 and TOF of 39473 ± 8 h−1 were achieved.

  1. Hang Xu, Xiao-Fang Liu, Chun-Shuai Cao, Bin Zhao*, Peng Cheng andLiang-Nian He*, A Porous Metal–Organic Framework Assembled by [Cu30] Nanocages: Serving as Recyclable Catalysts for CO2 Fixation with Aziridines. Advanced Science2016, 3(11), 1600048. [link]

Abstract: Based on a novel ligand 5-(2,6-bis(4-carboxyphenyl)pyridin-4-yl)isophthalic acid (H4BCP) with large skeletons, a unique porous framework {[Cu2(BCP)(H2O)2]·3DMF}n (1) assembled by nano-sized and censer-like [Cu30] cages is successfully obtained and structurally characterized. In 1, the large 1D channel in frameworks and window size in the nanocages can enrich methylene blue and capture CO2, exhibiting the promising applications in environmental protection. More importantly, the explorations on the cycloaddition reaction of CO2 and aziridines with various substituents suggest that can serve as an efficient heterogeneous catalyst for CO2 conversion with aziridines in a solvent-free system, which can be reused at least ten times without any obvious loss in catalytic activity. This is the first example of metal–organic framework (MOF)-based catalysts in converting CO2 into high-value oxazolidinones through activating aziridines and CO2, further extending the applications of MOFs materials in catalysis.

  1. Zhi-Hua Zhou, Qing-Wen Song, Jia-Ning Xie, Ran Ma,Liang-Nian He*, Silver(I)-Catalyzed Three-Component Reaction of Propargylic Alcohols, CO2 and Monohydric Alcohols: Thermodynamically Feasible Access to β-Oxopropyl Carbonates. Chem. Asian J.2016, 11, 2065-2071. [link]

Abstract: Silver(I)-catalyzed three-component reaction of propargylic alcohols, CO2, and monohydric alcohols was successfully developed for the synthesis of β-oxopropyl carbonates. As such, a series of β-oxopropyl carbonates were exclusively produced in excellent yields (up to 98%) even under atmospheric pressure of CO2. Silver catalyst in this study works efficiently for both the carboxylative cyclization of propargylic alcohols with CO2, and subsequent transesterification of α-alkylidene cyclic carbonates with monohydric alcohols, thus renders this tandem process performing smoothly under mild conditions. The present work provides a versatile and thermodynamically favorable approach to dissymmetric dialkyl carbonates.

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  1. Qing-Wen Song, Zhi-Hua Zhou, Mei-Yan Wang, Kan Zhang, Ping Liu, Jia-Yao Xun andLiang-Nian He*, Thermodynamically Favorable Synthesis of 2-Oxazolidinones through Silver-Catalyzed Reaction of Propargylic Alcohols, CO2, and 2-Aminoethanols, ChemSusChem, 2016, 9(16), 2054-2058. [link]

Abstract: Three in a pot: A thermodynamically feasible pathway for CO2 conversion is successfully performed to concurrently synthesize 2-oxazolidinones and α-hydroxyl ketones through a three-component reaction of propargylic alcohols, CO2, and 2-aminoalcohols. As a consequence, the thermodynamic limitation for the condensation reaction of 2-aminoalcohols and CO2 is circumvented by avoiding the dehydration step.

  1. Jia-Ning Xie, Zhen-Feng Diao, Chang Qiao, Ran Ma and Liang-Nian He*, One-pot stepwise synthesis of cyclic carbonates directly from olefins with CO2 promoted by K2S2O8/NaBr, J. CO2 Util.201616, 313-317. [link]

Abstract: Efficient synthesis of cyclic carbonates from olefins using K2S2O8 as oxidant and NaBr as “bromination” reagent has been developed through a reaction sequence involving hydroxybromination of olefins and subsequent carboxylation of the bromohydrin in situ generated with CO2. This process provides a novel and convenient access to cyclic carbonates in a one-pot stepwise fashion. Representative olefins with different functional groups could react smoothly under relatively mild (3 MPa, 60 °C) and transition metal-free conditions to afford various cyclic carbonates.

  1. Xiao-Fang Liu, Ran Ma, Chang Qiao, Han Cao,Liang-Nian He*, Fluoride-Catalyzed Methylation of Amines by Reductive Functionalization of CO2 with Hydrosilanes. Chem. Eur. J.2016, 22(46), 16489-16493. [link]

Abstract: An effective and inexpensive organocatalyst tetrabutylammonium fluoride (TBAF) was developed for the reductive functionalization of CO2 with amines to selectively afford formamides or methylamines by employing hydrosilanes. Hydrosilanes with different substituents show discriminatory reducing activity. Thus, the formation of formamides and further reduction products, that is, methylamines could be controlled by elegantly tuning hydrosilane types. Formamides were obtained exclusively under an atmospheric pressure of CO2 with triethoxysilane. Using phenylsilane as a reductant, methylamines were attained with up to 99 % yield at 50 °C coupled to a complete deoxygenation of CO2. The crucial intermediate silyl formate in the formylation step was identified and thereby a tentative mechanism involving the fluoride-promoted hydride transfer from the hydrosilane to CO2/formamide was proposed. Striking features of this metal-free protocol are formylation and methylation of amines by reductive functionalization of CO2 with hydrosilanes and mild reaction conditions.

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  1. Bing Yu andLiang-Nian He*. Upgrading Carbon Dioxide by Incorporation into Heterocycles, ChemSusChem2015, 8(1): 52-62. [link]

Abstract: CO2 in heterocycles: Direct incorporation of CO2 as the entire “CO2” moiety or “C=O” fragments into organic substrates can be successfully performed by carbonylative/carboxylative cyclization of the nitrogen/oxygen/carbon-nucleophilic species with CO2 or initiated by C-H bond activation, resulting in the formation of various heterocycles. These techniques stimulate further interest in upgrading CO2 from a waste into an ideal and sustainable chemical feedstock in organic synthesis.

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  1. Qing-Wen Song, Wei-Qiang Chen, Ran Ma, Ao Yu, Qiu-Yue Li, Yao Chang and Liang-Nian He*, Bifunctional Silver(I) Complex-Catalyzed CO2 Conversion at Ambient Conditions: Synthesis of α-Methylene Cyclic Carbonates and Derivatives, ChemSusChem2015, 8(5): 821-827. [link]

AbstractThe chemical conversion of CO2 at atmospheric pressure and room temperature remains a great challenge. The triphenylphosphine complex of silver(I) carbonate was proved to be a robust bifunctional catalyst for the carboxylative cyclization of propargylic alcohols and CO2 at ambient conditions leading to the formation of α-methylene cyclic carbonates in excellent yields. The unprecedented performance of [(PPh3)2Ag]2CO3 is presumably attributed to the simultaneous activation of CO2 and propargylic alcohol. Moreover, the highly compatible basicity of the catalytic species allows propargylic alcohol to react with CO2 leading to key silver alkylcarbonate intermediates: the bulkier [(Ph3P)2AgI]+ effectively activates the carbon–carbon triple bond and enhances O-nucleophilicity of the alkylcarbonic anion, thereby greatly promoting the intramolecular nucleophilic cyclization. Notably, this catalytic protocol also worked well for the reaction of propargylic alcohols, secondary amines, and CO2 (at atmospheric pressure) to afford β-oxopropylcarbamates.

>>> COVER OF THE ISSUE

  1. Chun-Xiang Guo, Bing Yu, Jia-Ning Xie and Liang-Nian He*, Silver tungstate: A single-component bifunctional catalyst for carboxylation of terminal alkynes with CO2 in ambient conditions. Green Chem.2015, 17(1): 474-479. [link]

Abstract: Silver tungstate was successfully developed as a bifunctional catalyst for the ligand-free carboxylation of various terminal alkynes with electron-withdrawing or electron-donating groups under atmospheric pressure of carbon dioxide (CO2) at room temperature. In this protocol, dual activation – i.e., the terminal alkyne activated by silver, and COactivation by the tungstate anion – was verified using nuclear magnetic resonance spectroscopy, and means that this reaction can be run under ambient conditions. Notably, this protocol can be applied to the preparation of a phenylacrylate derivative by a cascade reaction using phenylacetylene, CO2 and benzylamine as starting materials.

  1. An-Hua Liu, Bing Yu andLiang-Nian He*. Catalytic Conversion of Carbon Dioxide to Carboxylic Acid Derivatives. Greenhouse Gas Sci Technol2015, 5, 17-33. [link]

Abstract: Chemical utilization of the greenhouse gas, i.e., CO2 as an abundant, easily available, and renewable carbon feedstock for producing chemicals, materials, and fuels is attractive as an integral part of the carbon cycle. Based on the principle of CO2 activation and elaborately designed catalysts, various transformation of CO2 can be realized under mild conditions. In particular, establishing practical methodologies for catalytic carboxylation by CO2 as carboxylative reagent would be a fascinating dream for synthetic chemists. This review covers the updated advances in the catalytic conversion of CO2 into carboxylic acid derivatives from alkenes, alkynes, aromatic halides, aromatic C(sp2)-H bonds, etc.

  1. 5.Xian-Dong Lang,Shuai Zhang, Qing-Wen Song and Liang-Nian He*, Tetra-butylphosphonium arginine-based ionic liquid-promoted cyclization of 2-aminobenzonitrile with carbon dioxide, RSC Adv.2015, 5, 15668-15673. [link]

Abstract: An easily prepared amino acid ionic liquid (AAIL) i.e. [TBP][Arg] comprising a tetra-butylphosphonium cation and an arginine anion was found to be an efficient and recyclable catalyst for the synthesis of quinazoline-2,4(1H,3H)-diones from 2-aminobenzonitriles and CO2 under solvent-free conditions. As a result, various 2-aminobenzonitriles bearing electron-withdrawing or electron-donating substituents worked well to afford quinazoline-2,4(1H,3H)-diones in excellent yields. Notably, this type of AAIL showed good stability, and could be easily recovered and reused five times without significant loss of its catalytic activity. This process represents an alternative approach for greener chemical fixation of CO2 to afford valuable compounds.

  1. Xiu-Zhen Lin, Zhen-Zhen Yang, Liang-Nian He and Zhong-Yong Yuan*, Mesoporous zirconium phosphonates as efficient catalysts for chemical CO2 fixation. Green Chem.2015, 17, 795-798. [link]

Abstract: Mesoporous zirconium phosphonates were demonstrated as highly effective catalysts for the heterogeneously catalyzed cycloaddition reaction between aziridines and CO2 to yield oxazolidinones in a solvent-free system without introducing any co-catalysts or halogen species, exhibiting outstanding activity and selectivity, as well as excellent recyclability.

  1. Siyang Liu, Qingqing Zhu, Qingxin Guan,Liangnian He, Wei Li*, Bio-aviation fuel production from hydroprocessing castor oil promoted by the nickel-based bifunctional catalysts, Bioresource Technology2015 183: 93-100. [link]

Abstract: Bio-aviation fuel was firstly synthesized by hydroprocessing castor oil in a continuous-flow fixed-bed microreactor with the main objective to obtain the high yield of aviation fuel and determine the elemental compositions of the product phases as well as the reaction mechanism. Highest aviation range alkane yields (91.6 wt%) were achieved with high isomer/n-alkane ratio (i/n) 4.4–7.2 over Ni supported on acidic zeolites. In addition, different fuel range alkanes can be obtained by adjusting the degree of hydrodeoxygenation (HDO) and hydrocracking. And the observations are rationalized by a set of reaction pathways for the various product phases.

  1. Chun-Xiang Guo, Bing Yu, Ran Ma andLiang-Nian He*, Metal-promoted Carboxylation of Alkynes/allenes with Carbon Dioxide. Current Green Chemistry2015, 2(1), 14-25. [link]

AbstractCarbon dioxide is generally known as one of the main greenhouse gasses which have caused a series of environmental problems. On the other hand, CO2 can also be regard as an abundant, nontoxic, renewable and economical C1-synthon in organic synthesis. Chemical utilization of CO2 has attracted more and more attentions all over the world and has been studied extensively and intensely for decades. Meanwhile, acrylic acid is a valuable chemical which has been widely used in industry. From the point of sustainable development, the direct installation of CO2 into organic compounds to afford carboxylic acid derivatives is one of the most concise and promising ways for CO2 utilization. In this article, advances in the metal-promoted carboxylation reaction of alkynes and allenes with carbon dioxide are highlighted with mechanistic understanding on a molecular level.

  1. Xian-Dong Lang, Xiao-Fang Liu andLiang-Nian He*, Sustainable Solid Catalysts for Cyclic Carbonate Synthesis from CO2 and Epoxide, Current Organic Chemistry, 2015, 19, 681-694. [link]

Abstract: As a major contributor to greenhouse effect, detrimental influence of CO2 has received more and more attention. Meanwhile, CO2 is also a valuable C1 building block, with several distinguished features such as low cost, nontoxicity, nonflammability, renewal, abundance. CO2 fixation is one of the most important priorities of the scientific community dedicated to reduce global warming. The last few decades have witnessed enormous attention utilizing CO2 to produce a variety of organic molecules, such as cyclic carbonates, which hold diverse applications as polar aprotic solvents, intermediates for organic and polymeric synthesis, and chemical ingredients for pharmaceutical/ fine chemicals in biomedical applications, electrolytic elements of lithium secondary batteries. Development of sustainable solid catalysts for the cycloaddition of epoxide with CO2 into cyclic carbonates is of paramount importance from a viewpoint of C1 chemistry and green chemistry. In this mini-review, we would like to update the recent advances in development of efficient heterogeneous catalysts including polymeric ionic liquids, metal organic frameworks, conjugated microporous polymer, polyamines, functionalized ion-exchange resins, polystyrene-supported ionic liquids, chitosan-based heterogeneous catalysts, silica-supported catalysts, magnetic nanoparticle supported catalysts, metal oxide and polyoxometalate, and others for the cycloaddition of epoxide with CO2, and we hope this presentation will stimulate further interest in chemical conversion of CO2 using sustainable catalysts.

  1. 10. 李雨浓,何良年*.二氧化碳的原位催化氢化反应. 科学通报2015, 60(16): 1465-1487.  [link]

摘要:二氧化碳(CO2)的吸收和封存技术是规模化减缓CO2排放的手段之一, 但其脱附、压缩、运输和储存过程中, 不可避免地消耗能量. 同时, CO2作为无毒无害、廉价易得的C1资源, 可代替传统羰基化试剂合成高附加值的化工产品. 因此, CO2“变废为宝, 高值化利用”的研究, 特别是将CO2还原为甲酸、甲醇等能源类产品, 具有重要科学意义及应用价值. 着眼于CO2吸收和资源化利用相结合的策略, 将CO2的吸收产物进行原位催化反应, 既可绕过脱附、压缩环节; 又可消除高压反应的不足、减少设备投入及节能降耗; 同时, 吸收过程中CO2分子得到活化, 有利于后续化学转化反应在低压温和条件下进行. 催化氢化反应在多种CO2资源化利用途径中具有重要意义和应用前景, 将CO2的吸收产物进行原位催化氢化反应能够成功获得甲酸、甲醇等重要的能源产品. 本文概括介绍了CO2的捕集方法及其化学转化为衍生物的路径, 总结了CO2氢化反应的催化体系和作用机制, 在此基础上, 重点分析讨论了CO2的原位催化氢化反应机理和最新进展.

  1. Bing Yu, Jia-Ning Xie, Chun-Lai Zhong, Wei Li,* andLiang-Nian He*, Copper(I)@Carbon-Catalyzed Carboxylation of Terminal Alkynes with CO2 at Atmospheric Pressure. ACS Catal2015, 5, 3940-3944. [link]

Abstract: Activated carbon supported CuBr was found to be an efficient catalyst for the carboxylation of terminal alkynes under atmospheric pressure of CO2 using ethylene carbonate as solvent at 80 °C for only 2 h, as verified with 13CO2. Various terminal alkynes could react smoothly with CO2 and organic halides under the reaction conditions to afford the corresponding carboxylic esters. In addition, the catalyst can be easily recovered and reused at least five times without significant loss of activity.

  1. 12.Jia-Ning Xie, Bing Yu, Chun-Xiang Guo andLiang-Nian He*, Copper(I)/phosphine-catalyzed tandem carboxylation/annulation of terminal alkynes with ambient pressure of CO2: one-pot access to 3a-hydroxyisoxazolo[3,2-a]isoindol-8(3aH)-ones. Green Chem., 2015, 17(7), 4061-4067. [link]

Abstract: An efficient method for the synthesis of 3a-hydroxyisoxazolo[3,2-a]isoindol-8(3aH)-ones from CO2, terminal alkynes, EtBr, and NHPI (N-hydroxyphthalimide) was developed through the tandem carboxylation/annulation strategy catalyzed by copper(I)/phosphine system. This one-pot multicomponent reaction conducted at atmospheric CO2 pressure to afford the target products in good to excellent yields under mild conditions. Notably, a wide range of functional groups were tolerated in this procedure. This protocol with simultaneous formation of four novel bonds i.e. two C-C band and two C-O bond represents an efficient methodology for upgrading CO2 into heterocycles.

  1. Shuai Zhang, Wei-Qiang Chen, Ao Yu* and Liang-Nian He*, Palladium-Catalyzed Carboxylation of Benzyl Chlorides with Atmospheric Carbon Dioxide in Combination with Manganese/Magnesium Chloride, ChemCatChem2015, 7(23), 3972-3977. [link]

Abstract: An efficient direct carboxylation of a series of benzyl chlorides with CO2 catalyzed by Pd(OAc)2/dicyclohexyl (2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine (SPhos) was developed to afford the corresponding phenylacetic acids in combination with Mn powder as a reducing reagent and MgCl2 as an indispensable additive. The reaction proceeded smoothly under 1atm CO2. The application of Mn powder instead of a sensitive reducing reagent represents an operationally simple access to phenylacetic acids. Notably, MgCl2 is able to stabilize the (SPhos)2PdII(Bn)(Cl)(η1-CO2)(MgCl2) adduct and thus facilitates CO2 insertion into the PdII-C bond, which is supported by a DFT study.

  1. Qing-Wen Song,Liang-Nian He*Transition Metal-Promoted CO2 Conversion under Mild Reaction Conditions in Advances in CO2 Capture, Sequestration, and Conversion, Vol. 1194, American Chemical Society, 2015, pp. 47-70. [link]

Abstract: Carbon dioxide can be regarded as an inexpensive, abundant sustainable feedstock for producing value-added chemicals. Therefore, development of efficacious processes using CO2 as chemical feedstock under mild conditions particularly low CO2 pressure (ideally at 1 bar) could be still highly desirable. Accordingly, only if we understand the underlying principles of CO2 activation can the goal of using CO2 as an environmentally friendly and economically feasible source of carbon under mild reaction conditions be achieved. In this regard, transition metal catalysis based on CO2 activation for efficient chemical transformation of CO2 with outstanding selectivities is appealing from a standpoint of sustainable chemistry. In this context, great efforts have been devoted to constructing C-N and C-O bond on the basis of selecting high-energy starting materials and CO2 activation through molecular catalysis to overcome its thermodynamic stability and kinetic inertness. The aim of this chapter is to draw attention to the chemical fixation of CO2 with propargylic alcohols or propargylmines to a-alkylene cyclic carbonates, β-oxoalkylcarbamates and 2-oxazolidinones through various transition metal catalysis. This is an attractive strategy to utilize CO2 to produce useful products. A thorough overview of the catalytic utilization of CO2 with propargylic alcohols with gaining insights into the reaction mechanism is also presented.

  1. Qing-Wen Song, Zhi-Hua Zhou, Hong Yin,Liang-Nian He*, Silver(I)-Catalyzed Synthesis of β-Oxopropylcarbamates from Propargylic Alcohols and CO2 Surrogate: A Gas-Free Process, ChemSusChem2015, 8(23), 3967-3972. [link]

Abstract: The utilization of carbon dioxide poses major challenges owing to its high thermodynamic stability and kinetic inertness. To circumvent these problems, a simple reaction system is reported comprising ammonium carbamates as carbon dioxide surrogates, propargylic alcohols, and a silver(I) catalyst, for the effective conversion of a wide range of alcohols and secondary amines into the corresponding β-oxopropylcarbamates. A key feature of this strategy includes quantitative use of a carbon resource with high product yields under gas-free and mild reaction conditions. Notably, this catalytic protocol also works well for the carboxylative cyclization of propargylic amines and carbon dioxide surrogates to afford 2-oxazolidinones.

  1. Jia-Ning Xie, Bing Yu, Zhi-Hua Zhou, Hong-Chen Fu, Ning Wang,Liang-Nian He*, Copper(I)-based ionic liquid-catalyzed carboxylation of terminal alkynes with CO2 at atmospheric pressure, Tetrahedron Lett. 2015, 56(50), 7059-7062. [link]

Abstract: An ionic liquid containing copper(I) proved to be an effective homogeneous catalyst for the carboxylation of terminal alkynes with ambient CO2. This developed procedure needs no external ligands and terminal alkynes with various groups proceeded smoothly at atmospheric CO2 pressure and room temperature. Interestingly, the ILs containing copper(I) in both the anion and the cation showed much higher activity in comparison with the counterparts incorporating copper(I) solely in the form of halocuprate, that is, copper(I) in the anion. Especially, activated effect of the terminal alkyne by the ionic liquid was also validated by the NMR technique.

  1. Yu-Nong Li, Ran Ma, Liang-Nian He* and  Zhen-Feng Diao. Homogeneous hydrogenation of carbon dioxide to methanol. Catal. Sci. Technol.2014, 4(6), 1498-1512. [link]

Abstract: Carbon dioxide, a greenhouse gas mainly from the consumption of fossil fuel, is regarded as an attractive feedstock in view of synthetic chemistry. Great efforts have been devoted to developing catalytical processes for converting CO2 into value-added compounds with reduced carbon footprint. Among versatile applications in organic synthesis, CO2 can serve as a promising raw material for fuel production including methanol, CH4, etc. ‘Coming from fuel and returning to fuel’ is an appealing objective in terms of sustainable development associated with circumventing energy shortage and CO2 issue. To date, metal complexes and organocatalysts for CO2 hydrogenation to both liquefied and gaseous fuels have been developed along with the reaction mechanistic insight. Understanding the interaction of active catalytic species with CO2 or hydrogen could account for development of efficient homogeneous catalysts. In this context, homogeneous catalytic hydrogenation of CO2 and its derivatives into fuel-related products is highlighted in this article in combination with mechanistic understanding on a molecular level.

>>> COVER OF THE ISSUE

  1. Zhen-Zhen Yang, De-en Jiang, Xiang Zhu, Chengcheng Tian, Suree Brown, Chi-Linh Do-Thanh,Liang-Nian He* and Sheng Dai*. Coordination effect-regulated CO2 capture with an alkali metal onium salts/crown ether system. Green Chem., 2014, 16, 253-258. [link]

Abstract: A coordination effect was employed to realize equimolar CO2 absorption, adopting easily synthesized amino group containing absorbents (alkali metal onium salts). The essence of our strategy was to increase the steric hindrance of cations so as to enhance a carbamic acid pathway for CO2 capture. Our easily synthesized alkali metal amino acid salts or phenolates were coordinated with crown ethers, in which highly sterically hindered cations were obtained through a strong coordination effect of crown ethers with alkali metal cations. For example, a CO2 capacity of 0.99 was attained by potassium prolinate/18-crown-6, being characterized by NMR, FT-IR, and quantum chemistry calculations to go through a carbamic acid formation pathway. The captured CO2 can be stripped under very mild conditions (50 °C, N2). Thus, this protocol offers an alternative for the development of technological innovation towards efficient and low energy processes for carbon capture and sequestration.

  1. Yu-Nong Li, Zhen-Feng Diao,Liang-Nian He*, and Zhen-Zhen Yang, Carbon capture with simultaneous activation and its subsequent transformation. Advances in Inorganic Chemistry, Vol 65, Chapter 9, Elsevier Science, 2014, in press (Book Chapter invited by the editor)
  1. Qing-Wen Song, Bing Yu, Xue-Dong Li, Ran Ma, Zhen-Feng Diao, Rong-Guan Li, Wei Li* andLiang-Nian He*. Efficient chemical fixation of CO2 promoted by a bifunctional Ag2WO4/Ph3P system.  Green Chem., 2014, 16, 1633-1638. [link]

Abstract: An efficient heterogeneous silver-catalyzed reaction for construction of the α-methylene cyclic carbonate motif was developed through carboxylative assembly of propargyl alcohols and CO2. Such a CO2 fixation protocol proceeded smoothly with only 1 mol% of Ag2WO4 and 2 mol% of PPh3 as well as atmospheric CO2 at room temperature under solvent-free conditions, in an environmentally benign and low energy manner along with an easy operating procedure. Notably, up to 98% isolated yields of carbonates could be attained with exclusive chemo-selectivity. In addition, the dual activation capacity of Ag2WO4 towards both the propargylic substrate and CO2 is based on which cooperative catalytic mechanism by the silver cation and the tungstate anion is proposed. Recycling trials on carboxylative cyclization of propargyl alcohols and CO2 illustrate that the catalyst can be reused at least 4 times with retention of high catalytic activity and selectivity. Especially, it allows the direct and effective application in the one-pot synthesis of various oxazolidinones bearing exocyclic alkenes and carbamates in moderate to high yields upon the alternative introduction of primary or secondary amines.

  1. Bing Yu, Chun-Xiang Guo, Chun-Lai Zhong, Zhen-Feng Diao, Liang-Nian He*. Metal-free chemoselective oxidation of sulfides by in situ generated Koser’s reagent in aqueous media. Tetrahedron Lett., 2014, 55, 1818-1821. [link]

Abstract: Selective oxidation of sulfides was successfully performed by employing phenyliodine diacetate as oxidant with the catalysis of TsOH in aqueous solution under mild conditions. Sulfoxides were formed with 1.1 equiv. of PhI(OAc)2 at room temperature; whereas sulfones were obtained in the presence of 2.1 equiv. of PhI(OAc)2 at 80 °C under otherwise identical conditions. Notably, various sulfides were converted to corresponding sulfoxides or sulfones in good to high yields by this metal-free protocol.

  1. Ran Ma, Liang-Nian He*, Qing-Wen Song, Yue-Biao Zhou and Kai-Xuan Liu, Efficient hydrogenation of imines over Fe and ZnO powder in self-neutralizing acidic CO2/H2O system. RSC Adv.2014, 14, 11867-11871. [link]

Abstract: An environmentally benign process was developed for the reduction of imines with iron and zinc oxide-promoted in the reversible CO2/H2O system without any acid additive or organic solvent. H2O is considered to serve as the terminal hydrogen source. The reaction system could be inherently neutralized by readily removal of CO2, thus resulting in facile post-processing and none waste disposal. The highly flexible and chemo-selective reduction protocol affords the corresponding amines with intact other reducible substituents in good to excellent yields.

  1. Shuai Zhang, Yu-Nong Li, Ya-Wei Zhang, Liang-Nian He,* Bing Yu, Qing-Wen Song, Xian-Dong Lang, Equimolar Carbon Absorption by Potassium Phthalimide and In Situ Catalytic Conversion Under Mild Conditions, ChemSusChem2014, 7, 1484-1489. [link]

Abstract: In a fix: Potassium phthalimide is as an excellent absorbent for equimolar CO2capture with simultaneous activation. The in situ catalytic conversion of captured CO2 can be successfully converted into value-added chemicals and fuel-related products under mild conditions through a carbon capture and utilization pathway, rather than going through desorption process.

  1. Bing Yu, Zhen-Feng Diao, An-Hua Liu, Xu Han, Bin Li, Liang-Nian He* and Xiang-Ming Liu, Selective Oxidation of Sulfides to Sulfoxides with tert-Butylnitrite as An Alternative Oxidant, Curr. Org. Synth.2014, 11(1), 156-160. [link]

Abstract: Tert-butylnitrite was proved to be an efficient oxidant for the selective oxidation of sulfides to sulfoxides. The reaction was promoted by Fe(NO3)3·9H2O under mild conditions and various substrates were effectively converted into the corresponding sulfoxides in good yields and excellent selectivity.

  1. Ya-Nan Zhao, Bing Yu, Zhen-Zhen Yang andLiang-Nian He*, Magnetic base catalysts for the chemical fixation of carbon dioxide to quinazoline-2,4(1H,3H)-diones, RSC Adv., 2014, 4, 28941-28946. [link]

Abstract: TBD-functionalized Fe3O4 was proven to be an efficient and recyclable magnetic heterogeneous catalyst for the chemical fixation of CO2 with 2-aminobenzonitriles under mild conditions.

  1. Shuai Zhang andLiang-Nian He*, Capture and Fixation of CO2 Promoted by Guanidine Derivatives,  Aust. J. Chem. 2014, 67(7), 980-988. [link]

Abstract: Guanidine compounds and their derivatives can be developed as catalysts, additives, or promoters in organic synthesis due to their unique chemical properties, which have attracted much attention in the chemistry and catalysis communities. Particularly, the strong basicity and ease of structural modification allow them to offer wide applications in the field of CO2 capture and conversion. Guanidine compounds modified as ionic liquids or heterogeneous catalysts have also been developed for CO2 capture and conversion. In this context, the latest progress on CO2 capture using guanidine and their derivatives as absorbents with high capacity will be summarized. Furthermore, guanidine-catalyzed transformation of CO2 to a series of value-added chemicals with mechanistic consideration on a molecular level will be particularly elaborated in this article.

  1. Ran Ma, Cheng-Bin Huang, An-Hua Liu, Xue-Dong Li and Liang-Nian He*, An in situ acidic carbon dioxide/glycol system for aerobic oxidative iodination of electron-rich aromatics catalyzed by Fe(NO3)3·9H2O. Catal. Sci. Technol., 2014, 4, 4308-4312. [link]

Abstract: An environmentally benign CO2/glycol reversible acidic system was developed for the iron(III)-catalyzed aerobic oxidative iodination of electron-rich aromatics without the need for any conventional acid additive or organic solvent. Notably, moderate to high isolated yields (up to 97%) of the aryl iodides were attained with comparable regioselectivity when ferric nitrate nonahydrate was used as the catalyst with molecular iodine under 1 MPa of CO2.

  1. Zhen-Zhen Yang andLiang-Nian He*, Efficient CO2 capture by tertiary amine-functionalized ionic liquids through Li+-stabilized zwitterionic adduct formation, Beilstein J. Org. Chem., 2014, 10, 1959-1966. [link]

Abstract: Highly efficient CO2 absorption was realized through formation of zwitterionic adducts, combining synthetic strategies to ionic liquids (ILs) and coordination. The essence of our strategy is to make use of multidentate cation coordination between Li+ and an organic base. Also PEG-functionalized organic bases were employed to enhance the CO2-philicity. The ILs were reacted with CO2 to form the zwitterionic adduct. Coordination effects between various lithium salts and neutral ligands, as well as the CO2 capacity of the chelated ILs obtained were investigated. For example, the CO2 capacity of PEG150MeBu2N increased steadily from 0.10 to 0.66 (mol CO2 absorbed per mol of base) through the formation of zwitterionic adducts being stabilized by Li+.

  1. Yu-Nong Li,Liang-Nian He,*Xian-Dong Lang, Xiao-Fang Liu and Shuai Zhang, An integrated process of CO2 capture and in situ hydrogenation to formate using a tunable ethoxyl-functionalized amidine and Rh/bisphosphine system, RSC Adv.20144, 49995-50002.  [link]

Abstract: An integrated process of CO2 capture and in situ hydrogenation into formate was achieved in 95–99% yield using a tunable ethoxyl-functionalized amidine and Rh/bisphosphine system, being regarded as an alternative carbon capture and utilization approach to supply fuel-related products, to circumvent the energy penalty in carbon capture and storage. CO2 was captured by non-volatile amidine derivatives with simultaneous activation to form zwitterionic amidinium carbonate, and subsequent hydrogenation was facilitated by Rh/bisphosphine. The adsorption capacity and hydrogenation efficiency can be optimized by tuning the ethoxyl side chain. Particularly, the alkanolamidine bearing an intramolecular hydrogen donor derived from 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) gave both a high CO2 uptake (molar ratio of 0.95:1) and excellent hydrogenation yield (99%). Furthermore, the silica-supported alkanolamidine was readily recovered and reused with the retention of good performance. This kind of carbon capture and utilization pathway could be a potential energy-saving option for industrial upgrading of CO2 from waste to fuel-related products in a carbon neutral manner.

  1. Qing-Wen Song,Liang-Nian He*, Synthesis of 3-benzyl-5- methyleneoxazolidin-2-one from N-benzylprop-2-yn-1-amine and CO2 in Green Synthesis Volume 12014, pp 45-53; Synthesis of the 5-membered cyclic carbonates from epoxides and CO2 in Green Synthesis Volume 12014, pp 55-61 CRC Press Taylor @ Francis Group: Dallas. 
  1. 15.Ran Ma, Zheng-Fen Diao, Zhen-Zhen Yang,Liang-Nian He*Homogeneous Catalysis Promoted by Carbon Dioxide in Transformation and Utilization of Carbon Dioxide, Bhanage, Bhalchandra M.; Arai, Masahiko (Eds.); Series Editors: He, L.-N., Rogers, R.D., Su, D., Tundo, P., Zhang, Z.C., Series book  Green Chemistry and Sustainable Technology(ISSN: 2196-6982), Springer: Dordrecht Heidelberg, 2014, pp 337-368. [link]
  1. 16. Yu-Nong Li,Liang-Nian He*Zhen-Feng Diao, Zhen-Zhen Yang, Carbon Capture with Simultaneous Activation and its Subsequent Transformation, in Rudi van Eldik, Michele Aresta, editors: CO2Chemistry, Vol 66 (ISBN 978-0-12-420221-4)ADIOCH, Burlington: Academic Press, 2014, pp. 289-345.
  1. 17.Chun-Xiang Guo, Ran Ma,Liang-Nian He*, Metal-promoted Synthesis of Cyclic Carbonates from 1,2-diols and Carbon Dioxide, The Open Organic Chemistry Journal2014, 8: 6-14. [link]

Abstract: Chemical fixation of CO2 to value-added products/materials/fuel has attracted more and more attention from both academia and governmental agencies all over the worldsince CO2 is an easily available and sustainable C1resource with the advantage of being abundant, nontoxic, nonflammable and renewable. Synthesis of organic carbonates starting from CO2 is one of the most promising methodologies and has been widely investigated. The use of CO2 and 1,2-diols can bring many advantages, such as reusing the byproducts generated in the industrial dimethyl carbonate (DMC) process and simplifying the post purification process. In this paper, synthetic methods with reaction mechanism of ethylene carbonate (EC), propylene carbonate (PC) and glycerol carbonate from COand ethylene glycol (EG), or propylene glycol (PG) or glycerol are systematically discussed.

  1. 何良年,二氧化碳化学,北京:科学出版社,2013年第一版.前言
  1. Qing-Wen Song,Liang-Nian He*, Jin-Quan Wang, Hiroyuki Yasuda and Toshiyasu Sakakura*, Catalytic fixation of CO2 to cyclic carbonates by phosphonium chlorides immobilized on fluorous polymer, Green Chem.201315, 110-115. [link]

Abstract: Phosphonium chloride covalently bound to the fluorous polymer is proved to be an efficient and recyclable homogeneous CO2-soluble catalyst for organic solvent-free synthesis of cyclic carbonates from epoxides and CO2 under supercritical CO2 conditions. The catalyst can be easily recovered by simple filtration after reaction and reused with retention of high activity and selectivity. In addition, the effects of various reaction variables on the catalytic performance are also discussed in detail. The process represents a simpler access to preparing cyclic carbonates with the ease of homogeneous catalyst recycling.

  1. Ya-Nan Zhao, Zhen-Zhen Yang, Si-Hang Luo andLiang-Nian He*,Design of task-specific ionic liquids for catalytic conversion of CO2 with aziridines under mild conditions, Catal. Today2013200, 2-8. [link]

Abstract: A series of polyethylene glycol (PEG)-functionalized ionic liquids (ILs) were developed as recyclable and efficient catalysts for selective synthesis of 5-aryl-2-oxazolidinones from aziridines and CO2 without addition of any organic solvents or additives. In particular, high yields, chemo- and regio-selectivities of oxazolidinones were attained when BrDBNPEG150DBNBr (DBN: 1,5-diazabicyclo[4.3.0]non-5-ene) was used as the catalyst, presumably due to activation of CO2 by the ether linkage in the PEG backbone, and stabilization of the ring-opened species of aziridine by the delocalized cation BrDBNPEG150DBN+. Furthermore, the catalyst could be reused for over four consecutive cycles without appreciable loss of catalytic activity and selectivity. The effects of catalyst structure and various reaction parameters on the catalytic performance were also investigated in detail. It was demonstrated that the catalyst worked well for a variety of aziridines producing the corresponding oxazolidinones in good yields and excellent regio-selectivities. Therefore, this solvent-free process could thus represent an environmentally friendly approach for ILs-catalyzed conversion of CO2 into value-added chemicals.

  1. Zhen-Zhen Yang,Liang-Nian He*, Ya-Nan Zhao and Bing Yu, Highly Efficient SO2 Absorption and Its Subsequent Utilization by Weak Base/Polyethylene Glycol Binary System, Environ. Sci. Technol.2013, 47(3), 1598-1605. [link]

Abstract: A binary system consisting of polyethylene glycol (PEG, proton donor)/PEG-functionalized base with suitable basicity was developed for efficient gas desulfurization (GDS) and can be regarded as an alternative approach to circumvent the energy penalty problem in the GDS process. High capacity for SO2 capture up to 4.88 mol of SO2/mol of base was achieved even under low partial pressure of SO2. Furthermore, SO2 desorption runs smoothly under mild conditions (N2, 25 °C) and no significant drop in SO2 absorption was observed after five-successive absorption–desorption cycles. On the other hand, the absorbed SO2 by PEG150MeIm/PEG150, being considered as the activated form of SO2, can be directly transformed into value-added chemicals under mild conditions, thus eliminating the energy penalty for SO2 desorption and simultaneously realizing recycle of the absorbents. Thus, this SO2 capture and utilization (SCU) process offers an alternative way for GDS and potentially enables the SO2 conversion from flue gas to useful chemicals as a value-added process.

  1. Ran Ma, An-Hua Liu, Cheng-Bin Huang, Xue-Dong Li andLiang-Nian He*, Reduction of sulfoxides and pyridine-N-oxides over iron powder with water as hydrogen source promoted by carbon dioxide,Green Chem.2013, 15(5), 1274-1279. [link]

Abstract: A green process was developed for efficient reduction of sulfoxides and pyridine-N-oxides using the iron powder in the presence of H2O/CO2 to sulfides and pyridines, respectively. Notably, H2O is employed as terminal hydrogen source, and CO2 could enhance hydrogen generation through in situ formation of carbonic acid. Thus carbonic acid offers simple neutralization by depressurizing CO2 and the system can eliminate unwanted byproducts. The high generality and chemo-selectivity of this protocol were demonstrated by the scope of substrates, in which chlorine, vinyl group and benzene ring can be tolerated.

  1. Bing Yu, Zhen-Feng Diao, Chun-Xiang Guo,Liang-Nian He*, Carboxylation of olefins/alkynes with CO2 to industrially relevant acrylic acid derivatives, J. CO2 Utilization2013, 1, 60-68. (invited by editor) [link]

Abstract: Carbon dioxide utilization has continued to capture the interest of chemists worldwide due to global warming associated with positive carbon accumulation. As an environmentally friendly C1 feedstock, the reaction of carbon dioxide has been extensively investigated for several decades. On the other hand, acrylic acid is a valuable industrial product that is widely used for various important purposes in industry. From the point view of atom- and process-economical chemistry, the most concise and promising route for acrylic acid derivatives synthesis would be direct carboxylation of olefins or alkynes with carbon dioxide. In this review, we would like to discuss and update the latest advances on synthesis of acrylic acid derivatives from unsaturated hydrocarbons and carbon dioxide.

  1. Zhenfeng Diao, Bin Li, Bing Yu, Anhua Liu,Liangnian He*,Polyethylene glycol radical-initiated aerobic propargylic oxidation in dense carbon dioxide, J. Energy Chem., 2013, 22(3): 363-367. [link]

Abstract: The selective aerobic oxidation of alkynes to corresponding α,β-acetylenic ketones was achieved in polyethylene glycol/dense CO2/O2 biphasic system without any catalyst or additive. The effects of reaction parameters, e.g. temperature, CO2 pressure, PEG molecular weight and loading on the reaction were carefully examined. Moreover, various substrates worked well in the presence of PEG1000 under 5 MPa of CO2 and 2 MPa of O2 at 100 oC for 12 to 24 h and acceptable yield and selectivity could be obtained in most cases. Preliminary mechanistic investigations were also discussed.

>>> COVER OF THE ISSUE

  1. Bing Yu, Zhen-Feng Diao, Chun-Xiang Guo, Chun-Lai Zhong, Liang-Nian He*, Ya-Nan Zhao, Qing-Wen Song, An-Hua Liu and Jin-Quan Wang*. Carboxylation of terminal alkynes at ambient CO2 pressure in ethylene carbonate. Green Chem.2013, 15(9), 2401-2407. [link]

Abstract: The CuI-catalyzed carboxylation of terminal alkynes with CO2 and alkyl halides using ethylene carbonate as solvent under mild conditions was studied. DFT calculations reveal that the energy barrier of CO2 insertion into sp-hybridized Cu-C bond could be reduced by employing ethylene carbonate as solvent. Notably, the procedure was conducted under ambient CO2 pressure without external ligands. A broad range of substrates with electron-withdrawing group or electron-donating group gave the corresponding products in reasonable yields.

  1. 9.  Qing-Wen Song, Bing Yu, An-Hua Liu, Ying He, Zhen-Zhen Yang, Zhen-Feng Diao, Qing-Chuan Song, Xue-Dong Li andLiang-Nian He*.PEG400-enhanced synthesis of gem-dichloroaziridines and gem-dichlorocyclopropanes through the dichlorocarbene in situ generated. RSC Adv.2013, 3, 19009-19014. [link]

Abstract: PEG400 is employed as an efficient phase transfer catalyst for the cycloaddition reaction of imines with dichlorocarbene, which is generated in situ from chloroform and sodium hydroxide, to give gem-dichloroaziridines in moderate to excellent yields at ambient temperature. This protocol is also extended to the synthesis of cyclopropanes from a variety of alkenes. In this study, PEG400 behaves as a phase transfer reagent thanks to its ability to coordinate with alkali metal cations. Notably, the one-pot synthesis of gem-dichloroaziridines from benzaldehyde and aromatic amines has also been successfully performed. The in situ generated acid, derived from CO2 and H2O, can also be effectively applied to promote the amide synthesis via the gem-dichloroaziridine pathway. The application of the gem-dichlorocyclopropane as a platform chemical is also briefly demonstrated, to afford the 2-phenylacrylaldehyde derivative via a ring-opening reaction.

  1. Yu-Nong Li,Liang-Nian He*, An-Hua Liu, Xian-Dong Lang, Zhen-Zhen Yang, Bing Yu and Chao-Ran Luan. In situ hydrogenation of the captured CO2 to formate with polyethyleneimine and Rh/monophosphine system. Green Chem.2013, 15, 2825-2829. [link]

Abstract: CO2 in the air can be efficiently captured with simultaneous activation by PEI (polyethyleneimine) to form ammonium carbamate and/or carbonate species. Thus, the in situ hydrogenation of captured CO2 into energy-storage materials rather than going through the desorption of conventional CCS (carbon capture and storage) runs better in comparison with equivalent gaseous CO2, thus validating this potential application of CCU (carbon capture and utilization) for supplying renewable energy. PEI600 as an effective carbon absorbent in this study could also be assumed to serve as both ligand and base to promote the catalytic hydrogenation of captured CO2, consequently acting as a ‘hinge base’ to combine capture and hydrogenation processes. The pathway was studied by NMR and in situ FT-IR spectroscopy under CO2 pressure. This protocol could open up great potential in transforming the captured CO2 from waste to fuel-related products.

  1. An-Hua Liu, Jian Gao,Liang-Nian He*, Catalytic Activation and Conversion of Carbon Dioxide into Fuels/ Value-Added Chemicals Through C-C Bond Formation, in New and Future Developments in Catalysis. Activation of Carbon Dioxide, 1st edition. Suib, S. Ed.; Elsevier Inc.: Philadelphia, 2013, p81-147. [link]
  1. An-Hua Liu, Ran Ma, Chan Song, Zhen-Zhen Yang, Ao Yu*, Yu Cai, Liang-Nian He*, Ya-Nan Zhao, Bing Yu, Qing-Wen Song. Equimolar CO2 Capture by N-Substituted Amino Acid Salts and Subsequent Conversion, Angew. Chem. Int. Ed.2012, 51(45), 11306-11310. [link]

Abstract: N-substituted amino acid salts in poly(ethylene glycol) reversibly absorb CO2 in nearly 1:1 stoichiometry. Carbamic acid is thought to be the absorbed form of CO2; this was supported by NMR and in situ IR spectroscopy, and DFT calculations. The captured CO2 could be converted directly into oxazolidinones and thus CO2 desorption could be sidestepped.

  1. Zhen-Zhen Yang,  Liang-Nian He*,  Jian Gao,  An-Hua Liu and Bing Yu,Carbon dioxide utilization with C–N bond formation: carbon dioxide capture and subsequent conversion, Energy Environ. Sci.2012, 5, 6602-6639. [link]

Abstract: Carbon dioxide chemistry (in particular, capture and conversion) has attracted much attention from the scientific community due to global warming associated with positive carbon accumulation. The most widely used chemical absorption technique for carbon capture and storage/sequestration (CCS) would be essentially adopting amino-containing absorbents through formation of C–N bond in terms of mechanistic consideration. However, extensive energy input in desorption and compression process would be a crucial barrier to realize practical CCS. On the other hand, CO2 is very attractive as an environmentally friendly feedstock to replace the hazardous phosgene route for making commodity chemicals, fuels, and materials from a standpoint of green chemistry, whereas the reactions involving CO2 are commonly carried out at high pressure, which may not be economically suitable and also pose safety concerns. The challenge is to develop catalysts that are capable of activating CO2 under low pressure (preferably at 1 atm), and thus incorporating CO2 into organic molecules catalytically. We have proposed a carbon capture and utilization (CCU) strategy as an alternative approach to addressing the energy penalty problem in CCS. The essence of our strategy is to use captured CO2, also considered as the activated form of CO2, which could render this system suitable for accomplishing chemical transformation of CO2 under low pressure to avoid an additional desorption step. Indeed, CO2 could be activated through the formation of carbamate/alkyl carbonate with Lewis basic nitrogen species. In this review, we would like to discuss and update advances on CCU, particularly C–N bond formation with the production of oxazolidinones, quinazolines, carbamates, isocyanates and polyurethanes by using CO2 as C1 feedstock, and CO2 capture by amino-containing absorbents, including conventional aqueous solution of amine, chilled ammonia, amino-functionalized ionic liquids and solid absorbents such as amino-functionalized silica, carbon, polymers and resin, presumably leading to CO2‘s activation and thus subsequent conversion through C–N bond formation pathway.

>>> COVER OF THE ISSUE

  1.  Jian Gao, Qing-Wen Song, Liang-Nian He*, Zhen-Zhen Yang and Xiao-You Dou, Efficient iron(III)-catalyzed three-component coupling reaction of alkyne, CH2Cl2 and amine to propargylamine, Chem. Commun.2012. 48, 2024-2026. [link]

Abstract: Iron(III) was proved efficient catalyst for the three-component coupling reaction of aromatic terminal alkynes, CH2Cl2 and aliphatic secondary amines for the facile synthesis of propargylamines.

  1. Bin Li, An-Hua Liu, Liang-Nian He,* Zhen-Zhen Yang, Jian Gao and Kai-Hong Chen, Iron-catalyzed selective oxidation of sulfides to sulfoxides with the polyethylene glycol/O2 system, Green Chem., 2012, 14, 130-135. [link]

Abstract: Readily available iron compounds were found to be active catalysts for the selective oxidation of sulfide to sulfoxide with molecular oxygen as the oxidant in polyethylene glycol (PEG). As an indispensable component, PEG had a great promotive effect on the reaction. Notably, high conversion (>99%) along with excellent chemo-selectivity of up to 94% could be attained by using Fe(acac)2 as the catalyst at 100 oC. This methodology was proved to be applicable for the transformation of various aromatic and aliphatic sulfides into the corresponding sulfoxides with high selectivity. PEG is considered to play a crucial role in stablizing the Fe(IV)-oxo species formed in situ which is supposed to be responsible for the sulfide oxidation.

  1. Zhen-Zhen Yang, Ya-Nan Zhao, Liang-Nian He*, Jian Gao and Zhong-Shu Yin, Highly efficient conversion of carbon dioxide catalyzed by polyethylene glycol-functionalized basic ionic liquids, Green Chem.2012, 14, 519-527. [link]

Abstract: A series of polyethylene glycol (PEG)-functionalized basic ionic liquids (ILs) were developed for efficient CO2 conversion into organic carbonates under mild conditions. In particular, BrTBDPEG150TBDBr was proven to be a highly efficient and recyclable catalyst for the synthesis of cyclic carbonates without utilization of any organic solvents or additives. This is presumably due to the activation of epoxide assisted by hydrogen bonding and activation of CO2 by the ether linkage in the PEG backbone or through the formation of carbamate species with the secondary amino group in the IL cation on the basis of in situ FT-IR study under CO2 pressure. In addition, the subsequent transesterification of cyclic carbonate e.g. ethylene carbonate (EC) with methanol to dimethyl carbonate (DMC) can also be effectively catalyzed by BrTBDPEG150TBDBr, thanks to the activation of methanol by the secondary and tertiary nitrogen in the IL to easily form CH3O, realizing a so-called “one-pot two-stage” access to DMC from CO2without separation of cyclic carbonate by using one kind of single component catalyst. Therefore, this protocol represents a highly efficient and environmentally friendly example for catalytic conversion of CO2 into value-added chemicals such as DMC by employing PEG-functionalized basic ILs as catalysts.

  1. Bing Yu, An-Hua Liu,Liang-Nian He*Bin Li, Zhen-Feng Diao and Yu-Nong Li, Catalyst-free approach for solvent-dependent selective oxidation of organic sulfides with oxone, Green Chem., 2012, 14, 957-962. [link]

>>>Highlighted on Green Chemistry Blog

Abstract: Selective oxidation of sulfides was successfully performed by employing oxone (2KHSO5·KHSO4·K2SO4) as oxidant without utilization of any catalyst/additive under mild reaction conditions. Notably, the reaction can be controlled by the chosen solvent. When ethanol was used as the solvent, sulfoxides were obtained in excellent yield; the reaction almost exclusively gave the sulfone in water. Furthermore, this protocol worked well for various sulfides to the corresponding sulfoxides in ethanol or sulfones in water.

  1. Jian Gao, Qing-Wen Song,Liang-Nian He*, Chang Liu, Zhen-Zhen Yang, Xu Han, Xue-Dong Li and Qing-Chuan Song, Preparation of polystyrene supported Lewis acidic Fe(III) ionic liquid and its application in catalytic conversion of carbon dioxide, Tetrahedron2012, 68, 3835-3842.[link]

>>>Highlighted on SYNFACTS

Abstract: A polystyrene supported Lewis acidic iron-containing ionic liquid was proved to be recyclable and efficient heterogeneous catalyst for converting CO2 into cyclic carbonate without utilization of any organic solvent or additive. Excellent yields and selectivity were obtained under mild reaction conditions. Notably, the catalyst could be readily recovered and reused over five times without appreciable loss of catalytic activity. A possible catalytic cycle was proposed. The present protocol has successfully been applied to reactions of aziridine/propargyl amines with CO2. This kind of the catalyst presented herein would have great potential in industrial application thanks to its featured advantages.

  1. An-Hua Liu, Yu-Nong Li, andLiang-Nian He*, Organic synthesis using carbon dioxide as phosgene-free carbonyl reagent, Pure Appl. Chem. 2012, 84, 3, 581-602. (invited by editor) [link]

Abstract: CO2 is very attractive as a typical renewable feedstock for manufacturing commodity chemicals, fuel, and materials since it is an abundant, nontoxic, nonflammable, and easily available C1 resource. The development of greener chemical methodologies for replacing the utility of hazardous and environmentally undesirable phosgene largely relies on ingenious activation and incorporation of CO2 into valuable compounds, which is of paramount importance from a standpoint of green chemistry and sustainable development. Great efforts have been devoted to constructing C–C, C–O, and C–N bond on the basis of CO2 activation through molecular catalysis owing to its kinetic and thermodynamic stability. The aim of this article is to demonstrate the versatile use of CO2 in organic synthesis as the alternative carbonyl source of phosgene, with the main focus on utilization of CO2 as phosgene replacement for the synthesis of value-added compounds such as cyclic carbonates, oxa-zolidinones, ureas, isocyanates, and polymers, affording greener pathways for future chemical processes.

  1. An-Hua Liu, Ran Ma, Meng Zhang, Liang-Nian He*,In situ acidic carbon dioxide/water system for selective oxybromination of electron-rich aromatics catalyzed by copper bromide. Catal. Today, 2012, 194(1), 38-43.[link]

Abstract: Carbon dioxide, being one of the major greenhouse gases responsible for global warming, its atmospheric level grows ever faster since the beginning of industrial era. Great efforts have been devoted to developing versatile technologies/processes to adjust and manipulate the rapid growth of CO2 emission. Besides CO2 capture and storage/sequestration (CCS) to control its emission, chemical utilization of the captured CO2 (CCU) emerges to be a rational technique for economical benefits as well as environmental concerns. As for the aim of CO2 utilization, an environmentally benign CO2/water reversible acidic system was developed for the copper (II)-catalyzed selective oxybromination of electron-rich aromatics without the need of any conventional acid additive and organic solvent. Notably, up to 95% yields of the bromination products were attained with good regio-selectivity when cupric bromide was used as the catalyst and lithium bromide as a cheap and easy handling bromine source under supercritical CO2. The catalytic system worked well for electron-rich aromatics including ethers, sulfides and mesitylene. Carbonic acid in situ formed from CO2 and water is supposed to act as the proton donator in the Brønsted acid-promoted reaction. Notably, COin this study serves as a reaction medium and a promoter in conjunction with water and also provides safe environment for aerobic reactions. Given with excellent reaction efficiency as well as no need of neutralization disposal, this process thus represents an environmentally friendly approach for aerobic bromination of aromatics with essential reduction of CO2 emission as well as an economically beneficial way for application of captured CO2.

  1. Xiao-Yong Dou,Liang-Nian He*, Zhen-Zhen Yang, Proline-Catalyzed Synthesis of 5-Aryl-2-Oxazolidinones from Carbon Dioxide and Aziridines under Solvent-Free Conditions, Synth. Commun.2012, 42, 62-74. [link]

Abstract: Natural α-amino acids were proven to be ecofriendly and recyclable catalysts for the carboxylation of aziridines with CO2 without utilization of any organic solvents or additives. Notably, a series of 5-aryl-2-oxazolidinones were obtained in good yield together with excellent chemo- and regioselectivity under mild conditions using proline as the catalyst. Notably, the catalyst could be recycled more than five times after a simple separation procedure without appreciable loss of catalytic activity. This process represents a promising strategy for homogeneous catalyst recycling.

  1. Yu-Nong Li, Jin-Quan Wang*,Liang-Nian He*, Zhen-Zhen Yang, An-Hua Liu, Bing Yu and Chao-Ran Luan. Experimental and theoretical studies on imidazolium ionic liquid-promoted conversion of fructose to 5-hydroxymethylfurfural, Green Chem.2012, 14, 2752-2758. [link]

Abstract: A combined experimental and computational study on the imidazolium ionic liquid-promoted conversion of fructose to 5-hydroxymethylfurfural (HMF) was performed. In particular, 1-butyl-3-methyl-imidazolium bromide (BMImBr) was found to be unexpectedly effective for conversion of fructose into HMF without utilizing any other additive or catalyst. Under the optimized conditions, nearly 100% conversion of fructose with a 95% yield of HMF could be obtained. In addition, BMImBr could be easily recovered and reused over 6 times without significant loss of activity. This protocol represents a simple, recyclable and environmentally friendly pathway for HMF production. Furthermore, the detailed mechanism of the BMcImBr-promoted conversion of fructose into HMF was also studied through an in situ FT-IR technique, NMR and density functional theory calculations, and demonstrated that the hydrogen bond interaction between BMImBr and fructose could play an important role in promoting the dehydration of fructose. This work also provides further understanding at the molecular level of the reaction process for ionic liquid-promoted conversion of fructose to HMF.

  1. Zhen-Zhen Yang, Liang-Nian He*, Qing-Wen Song, Kai-Hong Chen, An-Hua Liu and Xiang-Ming Liu, Highly efficient SO2 absorption/activation and subsequent utilization by polyethylene glycol-functionalized Lewis basic ionic liquids, Phys. Chem. Chem. Phys.2012, 14, 15832-15839. [link]

Abstract: Up to now, flue-gas desulfurization (FGD) is one of the most effective techniques to control SO2 emission from the combustion of fossil fuels. The conventional technology for FGD poses serious inherent drawbacks such as formation of byproducts and volatilization of solvents. In this work, polyethylene glycol (PEG)-functionalized Lewis basic ionic liquids (ILs) derived from DABCO were proved to be highly efficient absorbents for FGD due to its specific features such as high thermal stability, negligible vapor pressure, high loading capacity. Notably, PEG150MeDABCONTf2 gave an extremely high SO2 capacity (4.38 mol mol−1 IL), even under 0.1 bar SO2 partial pressure (1.01 mol mol−1 IL), presumably owing to the strong SO2-philic characterization of the PEG chain. Furthermore, the absorbed SO2 could be easy to release by just bubbling N2 at room temperature, greatly reducing energy requirement for SO2 desorption. In addition, SO2/CO2 selectivity (110) of PEG150MeDABCONTf2 is two times larger than the non-functionalized imidazolium IL (45). On the other hand, through activation of SO2 with the tertiary nitrogen in the cation, Lewis basic ILs such as PEG150MeDABCOBr proved to be efficient catalysts for the conversion of SO2 to some value-added chemicals such as cyclic sulfites without utilization of any organic solvent or additive. Thus, this protocol would pave the way for the development of technological innovation towards efficient and low energy demanded practical process for SO2 absorption and subsequent transformation.

  1. Zhen-Zhen Yang,Liang-Nian He*, An-Hua Liu and Yu-Nong Li, Catalytic fixation of carbon dioxide into fuel and chemicals, inKirk-Othmer Encyclopedia: Carbon Dioxide, Chemical Fixation, John Wiley & Sons: NJ, 2012. [link]
  1. Zhen-Zhen Yang, Qing-Wen Song,Liang-Nian He*,Capture and Utilization of Carbon Dioxide with Polyethylene Glycol, (SpringerBriefs in Molecular Science/SpringerBriefs in Green Chemistry for Sustainability), ISBN-10: 3642312675. [link]
  1. Qing-Wen Song, Ya-Nan Zhao,Liang-Nian He*, Jian Gao, Zhen-Zhen Yang, Synthesis of Oxazolidinones/Polyurethanes from Aziridines and CO2Current Catalysis2012, 1(2), 107-124. [link]

Abstract: From the viewpoint of sustainable development, chemical fixation/utilization of CO2 in an environmentally benign manner has been drawing much interest, especially in the field of organic chemistry. In this review, 100% atom economical routes such as the reaction of CO2 and aziridines to prepare oxazolidinones and polyurethanes with more consideration given to the catalytic strategies and insight into the reaction mechanism are reviewed in the context of CO2 conversion into useful chemicals. High atom efficiency of the reaction and wide application of the CO2-derived products are the main driving force for the constant interest paid to catalytic conversion of CO2 into fuels, value-added chemical, polycarbonate materials.

  1. Zhen-Zhen Yang, Ya-Nan Zhao,Liang-Nian He*,Task-specific ionic liquid-catalyzed conversion of carbon dioxide into fuel additive and value-added chemicals, in Handbook of Ionic Liquid: Properties, Applications and Hazards (ISBN 978-1-62100-349-6); Mun, J., and Sim, H., Ed.; Nova Science Publishers: NY, 2012, p. 227-256. [link]
  1.  Cheng-Xia Miao, Jin-Quan Wang, Bing Yu, Wei-Guo Cheng, Jian Sun, Sébastien Chanfreau, Liang-Nian He* and Suo-Jiang Zhang*, Synthesis of bimagnetic ionic liquid and application for selective aerobic oxidation of aromatic alcohols under mild conditions, Chem. Commun.2011, 47, 2697-2699. [link]

Abstract: The first bimagnetic ionic liquid based on Fe and TEMPO with cooperative functionalities not only exhibited strong paramagnetic behaviour at room temperature under an applied magnetic field of 5000 Oe but also proved to be an effective catalyst for selective aerobic oxidation of aromatic alcohols under mild and clean conditions.

  1. Cheng-Xia Miao, Bing Yu andLiang-Nian He*, Tert-butyl nitrite: a metal-free radical initiator for aerobic cleavage of benzylic C=C bond in compressed carbon dioxide, Green Chem.2011, 13 (3), 541-544.[link]

Abstract: Tert-butyl nitrite easily releasing alkoxyl radical and NO in combination with compressed CO2 under metal free condition was applied to efficiently and selectively initiate aerobic cleavage of benzylic C=C bonds. Notably, compressed CO2 in this study not only provides a safe reaction environment but also tunes the selectivity.

  1. Jian Gao, Jin-Quan Wang, Qing-Wen Song and Liang-Nian He*, Iron(III)-based ionic liquid-catalyzed regioselective benzylation of arenes and heteroarenes. Green Chem.2011, 13(5), 1182-1186.[link]

Abstract: An easily prepared Fe(III)-derived Lewis acid ionic liquid ([C4mim][FeCl4]), being comprised of 1-butyl-3-methyl imidazolium cation and tetrachloroferrate anion, was found to be an efficient, recyclable catalyst for benzylation of various arenes/heteroarenes into the diarylmethanes derivatives under mild reaction conditions without utilization of additional organic solvent. Interestingly, the acidity of [C4mim][FeCl4] could account for its catalytic activity in promoting the Lewis acid-catalyzed alkylation. Notably, this type of Fe(III)-based ionic liquid (IL) shows excellent stability, and could be easily recovered, and reused for five times without significant loss of its catalytic activity.

  1. Zhen-Zhen Yang, Liang-Nian He,* Ya-Nan Zhao, Bin Li and Bing Yu, CO2 capture and activation by superbase/polyethylene glycol and its subsequent conversion, Energy Environ. Sci.2011, 4(10), 3971-3975.[link]

Abstract: A highly efficient binary system consisting of a polyethylene glycol and an amidine or guanidine superbase was developed for CO2 absorption, leading to activation of CO2 molecule; and thus direct conversion of the captured CO2 to value-added chemicals or fuels was successfully performed to avoid desorption process.

  1. Zhen-Zhen Yang, Yu-Nong Li, Yang-Yang Wei andLiang-Nian He*, Protic onium salts-catalyzed synthesis of 5-aryl-2-oxazolidinones from aziridines and CO2 under mild conditions, Green Chem., 201113, 2351-2353.[link]

Abstract: Protic onium salts, e.g. pyridium iodide, proved to be highly efficient and recyclable catalysts for the selective synthesis of 5-aryl-2-oxazolidinones under a CO2 atmosphere at room temperature, presumably due to aziridine activation assisted by hydrogen bonding on the basis of 1H NMR and in situ FT IR under CO2 pressure study.

  1. Zhen-Zhen Yang, Ya-Nan Zhao,Liang-Nian He*, CO2 chemistry: Task-specific ionic liquids for CO2 capture/activation and subsequent conversion, RSC Adv.2011(4), 545-567 (invited by editor). [link]

>>> Top 10 cited review articles in RSC Adv (in 2012)

Abstract: Ionic liquids (ILs), a kind of novel green media composed entirely of cations and anions, have attracted considerable attention due to their unique properties such as non-volatility, tunable polarity, high stability and so on. In this article, the latest progress on the absorption and subsequent conversion of CO2 by using ILs as absorbents, catalysts or promoters will be summarized. The chemical absorption performance of ILs, especially task-specific ionic liquids (TSILs) such as amino-functionalized ILs, superbase-derived protic ILs has been systematically illustrated. Although significant advances have been made, extensive energy input in desorption process to recover absorbents would be still a crucial barrier to realize practical carbon capture and sequestration (CCS). On the other hand, efficient applications of CO2 in the synthesis of valuable compounds such as organic carbonates, urea derivatives, oxazolidinones and formic acid can also be promoted by employing TSILs as catalysts/reaction media. We anticipate that an integration of chemical capture of COwith its utilization, a so-called CO2 capture and utilization (CCU) protocol would be an ideal strategy to solve the energy penalty problem in common CCS without the need of heat desorption. The essence of this CCU concept is to use TSILs for CO2 capture and substantial activation, which could render catalytic transformation of CO2 to accomplish smoothly under low pressure (ideally at 1 atm).

  1. Jing-Lun Wang, Cheng-Xia Miao, Xiao-Yong Dou, Jian Gao, Liang-Nian He*, Carbon Dioxide in Heterocyclic Synthesis, Curr. Org. Chem.2011, 15(5), 621-646. (invited by editor) [link]

Abstract: As an abundant, nontoxic, nonflammable, easily available, and renewable carbon resource, carbon dioxide is very attractive as an environmentally friendly feedstock for making commodity chemicals, fuels, and materials. Owing to its kinetic and thermodynamic stability, significant efforts have been directed towards constructing C-C, C-O and C-N bond on the basis of CO2 activation through molecular catalysis. Development of catalytic methodologies for chemical transformation of CO2 into useful compounds is of paramount importance from a standpoint of C1 chemistry and green chemistry. The aim of this review is to demonstrate the versatile use of CO2 in heterocyclic synthesis, with the main focus on utilization of CO2 as a building block for synthesis of five- and six-membered heterocyclic compounds such as cyclic carbonates, oxazolidinones, imidazolidinones, lactones, quinazolines, etc. The potential use of dense CO2 as an alternative solvent and otherwise specific roles in the heterocyclic synthesis are also evaluated. We hope this presentation will stimulate further interest in research that may pave the way for selective synthesis of heterocycles employing CO2 as a synthon.

  1. Jian Gao, Bing Yu, Liang-Nian He*Reduction of Carbon Dioxide to Energy-Rich Products in Production and Purification of Ultraclean Transportation Fuels; Hu, Y. H., Ed.; ACS Symposium Series; American Chemical Society: Washington DC, 2011; Vol. 1088, pp 143-174.[link]
  1. Zhen-Zhen Yang, Xiao-Yong Dou, Fang Wu,Liang-Nian He*, NaZSM-5-catalyzed dimethyl carbonate synthesis via the ​transesterifi​cation of ethylene carbonate with methanol, Can. J. Chem.2011, 544-548.[link]

AbstractNaZSM-5 zeolite was found to be an efficient heterogeneous catalyst for the synthesis of dimethyl carbonate (DMC), which can serve as a building block, an additive to fuel oil, and an electrolyte in batteries, via the transesterification of ethylene carbonate (EC) with methanol. Notably, 77% DMC yield and 97% selectivity were achieved under mild reaction conditions. Furthermore, the effects of various reaction parameters such as catalyst loading, reaction time, and methanol/EC molar ratio on the catalytic performance were investigated in detail. This protocol was found to be applicable to a variety of alcohols, producing the corresponding dialkyl carbonates with moderate yields and selectivities. Moreover, the catalyst can be recovered by simple filtration with retention of catalytic activity; a stable crystal configuration and a slight alteration of its superficial structure were observed by X-ray diffraction and BET measurements.

  1. X-Y Dou, Q. Shuai,Liang-Nian He*, C.-J. Li*, Rhodium-catalyzed arylation of α-Amido Sulfones with Arylboronic Acids in Water-Toluene Biphasic Reaction System, Inorg. Chim. Acta2011, 369(1), 284-287.[link]

Abstract: An efficient method for the synthesis of N-protected diaryl-methyl-amines was developed through a rhodium-catalyzed arylation of α-amido sulfones with arylboronic acids in water-toluene biphasic system. Base combined with surfactant played a key role in this water-toluene biphasic reaction system. A diverse range of α-branched amines derivatives bearing different functional groups were obtained within 10 minutes under control conditions.

  1. Yu-Nong Li, Jing-Lun Wang andLiang-Nian He*, Copper(II) chloride-catalyzed Glaser oxidative coupling reaction in polyethylene glycol, Tetrahedron Lett.2011, 52 (27), 3485-3488.[link]

Abstract: Polyethylene glycol was shown to be an environmentally benign reaction medium for the copper(II) salt -catalyzed Glaser coupling reaction of terminal alkynes. In particular, oxygen as the sole oxidant worked very well for arylacetylenes even in short reaction time. The product was easily separated by extraction and the catalytic system could be reused four times without significant loss of reactivity.

  1. De-Lin Kong,Liang-Nian He*, Jin-Quan Wang, Polyethylene Glycol-Enhanced Chemoselective Synthesis of Organic Carbamates from Amines, CO2 and Alkyl Halides, Synth. Commun.2011, 41 (22), 3298-3307.[link]

Abstract: An efficient and environmentally benign method for the synthesis of organic carbamates was developed. Amines, CO2 and alkyl halides underwent a three-component reaction with the aid of K2CO3 and polyethylene glycol (PEG400, MW=400), affording the organic carbamates under ambient conditions. PEG could presumably act as a solvent, phase transfer catalyst (PTC). Notably, the presence of PEG could also depress the alkylation of both the amine and the carbamate, thus resulting in enhanced selectivity toward the target carbamate.

  1. Sébastien Chanfreau, Bing Yu, Liang-Nian He* and Olivier Boutin, Electrochemical determination of ferrocene diffusion coefficient in [C6MIM][PF6]-CO2 biphasic system, J. Supercrit. Fluid.2011, 56 (2), 130-136. [link]

Abstract: Diffusion coefficient is an important property in chemical industry and precise measurements can be achieved by electrochemical techniques. Study of ferrocene diffusion was carried out in 1-hexyl-3-methyl imidazolium hexafluorophosphate-dense CO2 ([C6MIM][PF6-CO2]) biphasic system using microelectrode technique. Diffusion coefficients were determined by cyclic voltammetry and Randles–Ševčík relationship in the temperature and pressure ranging from 303.15-333.15 K and 1-10 MPa, respectively. Computed phase simulations were also used. Two-phase system was determined whatever experimental conditions and composition tested. Volumes of heavy and light phase were estimated as well. Both electroanalytical and computed studies showed that [C6MIM][PF6]-CO2 biphasic system containing initial molar fraction of CO2 up to 0.9 can be used without decrease in diffusion coefficient values. The order of magnitude of these diffusion coefficients of ferrocene in greener aprotic media are about 10−6 m2·s−1.

  1. An-Hua Liu,Liang-Nian He,*Fang Hua, Zhen-Zhen Yang, Cheng-Bin Huang, Bing Yu and Bin Li, In situ Acidic Carbon Dioxide/Ethanol System for Selective Oxybromination of Aromatic Ethers Catalyzed by Copper Chloride, Adv. Synth. Catal.2011, 353, 3187-3195. [link]

Abstract: An environmentally benign carbon dioxide/ethanol reversible acidic system was developed for the copper(II)-catalyzed regioselective oxybromination of aromatic ethers without the need of any conventional acid additive and organic solvent. Good to excellent yields together with very good regioselectivity were achieved when easily available cupric chloride dihydrate was used as catalyst and lithium bromide as the cheap and easy-to-handle bromine source under supercritical carbon dioxide conditions. Notably, the catalytic system worked well for a wide range of aromatic ethers including sulfides, resulting in the formation of the mono-brominated products in high yields and exclusive regioselectivity. The alkylcarbonic acid in situ formed from ethanol and carbon dioxide is assumed to play the crucial role in the Brønsted acid-promoted reaction, which could probably act as the proton donator, and was studied employing in situ FT-IR technique under carbon dioxide pressure by monitoring the vibration shift of the hydroxy group of ethanol. Given with excellent bromine atom efficiency as well as no need of neutralization in waste disposal, this approach thus represents a greener pathway for the aerobic bromination of aromatic ethers. A possible catalytic cycle for the in situ alkylcarbonic acid-assisted oxybomination and the effect of supercritical carbon dioxide, i.e., activation of alcohol and enhancement of mass transfer are also discussed.

  1. S. Chanfreau,L.-N. He* and B. Yu, Electrochemical Behaviour of Ferrocene/Ferricinium Redox System in Pure and CO2 Saturated [C6MIM][PF6], ASEAN J. Chem. Eng.201111, 53-58.
  1. 16.Liang-Nian He,Xiao-Yong Dou, Yu-Song Gao, Feng Ye, Biomass-based energy: castor-derived biodegrabable lubricate and biodiesel from laboratory to pilot plant,  Pap.-Am. Chem. Soc., Div. Fuel Chem. 2011, 56 (1), 15-16.
  1. Liang-Nian He, Zhen-Zhen Yang, An-Hua Liu, Jian Gao,Carbon dioxide chemistry: ionic liquids-catalyzed transformation of CO2 into fuel additives and value addied chemicas, Prep. Pap.-Am. Chem. Soc., Div. Fuel Chem. 2011, 56 (1), 331-332.
  1. Cheng-Xia Miao,Liang-Nian He*, Jing-Lun Wang, Fang Wu, Self-Neutralizing in Situ Acidic CO2/H2O System for Aerobic Oxidation of Alcohols Catalyzed by TEMPO Functionalized Imidazolium Salt/NaNO2J. Org. Chem.2010, 75(1), 257-260. [link]

Abstract: A recyclable TEMPO functionalized imidazolium salt ([Imim-TEMPO][Cl]) and NaNO2 as the NO resource to activate dioxygen were developed to selectively oxidize a series of aliphatic, allylic, heterocyclic and benzylic alcohols to the respective carbonyl compounds in a reversible in situ acidic CO2/H2O system, which avoids using any acid, whereby can eliminate unwanted byproducts, facilitate reaction and ease separation of the catalyst and product.

  1. Zhen-Zhen Yang,Liang-Nian He,* Cheng-Xia Miao, and Sébastien Chanfreau, Lewis Basic Ionic Liquids-Catalyzed Conversion of Carbon Dioxide to Cyclic Carbonate, Adv. Synth. Catal., 2010, 352, 2233-2240. [link]

Abstract: A series of easily prepared Lewis basic ionic liquids were developed for cyclic carbonate synthesis from epoxide and carbon dioxide at low pressure without utilization of any organic solvents or additives. Notably, quantitative yield together with excellent selectivity were attained while 1,8-diazabicyclo[5.4.0]undec-7-enium chloride ([HDBU]Cl) was used as a catalyst. Furthermore, the catalyst could be recycled over five times without appreciable loss of catalytic activity. The effects of the catalyst structure and various reaction parameters on the catalytic performance were in detail investigated. This protocol was found to be applicable to a variety of epoxides producing the corresponding cyclic carbonates in high yields and selectivity. Therefore, this solvent-free process thus represents an environmentally friendly example for catalytic conversion of carbon dioxide into value-added chemicals by employing Lewis basic ionic liquids as catalyst. A possible catalytic cycle for hydrogen bond-assisted ring-opening of epoxide and carbon dioxide’s activation induced by nucleophilic tertiary nitrogen of the ionic liquid was also proposed.

  1. Xiao-Yong Dou, Qi Shuai,Liang-Nian He,* Chao-Jun Li,* Copper(II) Triflate Catalyzed Three-Component Coupling of Aldehydes, Alkynes and Carbamates, Adv. Synth. Catal., 2010, 352, 2437-2440. [link]

Abstract: A simple and efficient synthesis of propargylcarbamates was developed through a copper(II) triflate-catalyzed coupling of aldehydes, alkynes and carbamates. No co-catalyst or ligand is required.

  1. Zhen-Zhen Yang,Liang-Nian He,* Shi-Yong Peng, An-Hua Liu, Lewis Basic Ionic Liquids-Catalyzed Synthesis of 5-Aryl-2-oxazolidinones from Aziridines and COunder Solvent-Free Conditions, Green Chem.2010, 12, 1850-1854. [link]

Abstract: A type of DABCO-Derived Lewis basic ionic liquid was developed as a recyclable and efficient catalyst for selective synthesis of 5-aryl-2-oxazolidinones from aziridines and CO2 without utilization of any organic solvent or additive. Therefore, this solvent-free process represents an environmentally friendly process for ionic liquid-catalyzed conversion of CO2 into value-added chemicals.

  1. Jian Gao,Liang-Nian He*, Cheng-Xia Miao, Sébastien Chanfreau, Chemical fixation of CO2: efficient synthesis of quinazoline-2, 4-(1H, 3H)-diones catalyzed by guanidines under solvent-free conditions, Tetrahedron2010, 66, 4063-4067. [link]

Abstract: Guanidines were proved to be efficient catalysts for the chemical fixation of carbon dioxide with 2-aminobenzonitriles under solvent-free conditions. Notably, the catalysts with low loading worked well for a variety of 2-aminobenzonitriles. As a result, quinazoline-2, 4-(1H, 3H)-diones by employing present protocol were obtained in good yields under mild conditions. This process represents an alternative approach for the greener chemical fixation of CO2 to afford valuable compounds.

  1. Zhen-Zhen Yang,Liang-Nian He*, Xiao-Yong Dou, Sébastien Chanfreau, Dimethyl carbonate synthesis catalyzed by DABCO-derived basic ionic liquids via transesterification of ethylene carbonate with methanol, Tetrahedron Lett., 2010, 51, 2931-2934. [link]

Abstract: Easily prepared, thermal, water and air stable DABCO(1,4-diazobicyclo[2.2.2] octane)-derived basic ionic liquids were proved to be efficient catalysts for DMC synthesis from ethylene carbonate and methanol. [C4DABCO]OH (1-Butyl-4-azo-1-azoniabicyclo[2.2.2]octane hydroxide) showed excellent catalytic activity and 81% DMC yield together with 90% EC conversion was obtained under mild reaction conditions.

  1. De-Lin Kong,Liang-Nian He,* Jin-Quan Wang, Synthesis of Urea Derivatives from CO2 and Amines Catalyzed by Polyethylene Glycol-Supported Potassium Hydroxide without Dehydrating Agents, Synlett2010, (08), 1276-1280. [link]

Abstract: Polyethylene glycol supported potassium hydroxide (KOH/PEG1000) was developed as a recyclable catalyst for facile synthesis of urea derivatives from amines and CO2 without utilization of additional dehydrating agents. Primary aliphatic amines, secondary aliphatic amines, and diamines can be converted into the corresponding urea derivatives in moderate yields. Furthermore, the catalyst can be recovered after a simple separation procedure, and reused over 5 times with retention of high activity.

  1. Xiao-Yong Dou,Liang-Nian He,* Zhen-Zhen Yang, Jing-Lun Wang, Catalyst-Free Process for the Synthesis of 5-Aryl-2-Oxazolidinones via Cyclo-addition Reaction of Aziridines and Carbon Dioxide, Synlett2010, (14), 2159-2163. [link]

Abstract: A simple approach for facile synthesis of 5-aryl-2-oxazolidinones in excellent regio-selectivity from aziridines under compressed CO2 conditions was developed in the absence of any catalyst and organic solvent. The reaction outcome was found to be tuned by subtly adjusting CO2 pressure. The adduct formed in situ of aziridine and CO2 is assumed to act as a catalyst in this reaction, which was also studied by means of in situ FT-IR technique.

  1. De-Lin Kong,Liang-Nian He*, Jin-Quan Wang, Facile synthesis of oxazolidinones catalyzed by n-Bu4NBr3/n-Bu4NBr directly from olefins, chloramine-T and carbon dioxide, Catal. Commun., 2010, 11, 992-995. [link]

Abstract: A binary catalyst system composed of n-Bu4NBr3/n-Bu4NBr was developed for facile synthesis of 5-substituted 2-oxazolidinones with perfect regioselectivity in a single operation directly from olefins, chloramine-T and CO2.

  1. An-Hua Liu,Liang-Nian He*, Shi-Yong Peng, Zhong-Da Pan, Jing-Lun Wang, Jian Gao, Environmentally benign chemical fixation of CO2 catalyzed by the functionalized ion-exchange resins, Sci. China Chem., 2010, 53(7), 1578-1585. (invited by editor) .[link]

Abstract: Basic ion-exchange resins, one kind of polystyryl supported tertiary amines, were proved to be highly efficient and recyclable catalysts for the fixation of carbon dioxide with aziridines under mild conditions, leading to formation of 5-aryl-2-oxazolidinone with excellent regio-selectivities. Notably, neither solvent nor any additives were required, and the catalyst can be recovered by simply filtration and directly reused at least five times without significant loss of catalytic activity and selectivity. To be delighted, the present protocol was successfully applied to reactions of epoxides /propargyl amines with CO2/CS2. In general, this solvent-free process thus represents environmentally friendly catalytic conversion of CO2 into value-added chemicals and has great potential to be applied in various continuous flow reactors in industry.

  1. Fang Wu, Xiao-Yong Dou,Liang-Nian He*, and Cheng-Xia Miao, Natural Amino Acid-Based Ionic Liquids as Efficient Catalysts for the Synthesis of Cyclic Carbonates from CO2 and Epoxides under Solvent-Free Conditions, Lett. Org. Chem.2010, 7(1), 73-78. [link]

Abstract: Natural α-amino acids-derived ionic liquids comprising 1-butyl-3-methylimidazolium cation and amino acid anion, i.e. [bmim][AA] were found to be effective catalysts for the coupling of various epoxides and CO2 to produce cyclic carbonates in good yields and selectivity, which requires no additional organic solvent and avoids halogen.

  1. Liang-Nian He*, Zhen-Zhen Yang, An-Hua Liu, Jian Gao, CO2Chemistry at Nankai Group: Catalytic Conversion of CO2 into Value-Added Chemicals, ACS Series Book “Advances in CO2 Conversion and Utilization 2010, Chapter 6, pp77-101(Book chapter invited by editor) [link]
  1. 高健,苗成霞,汪靖伦,何良年*,二氧化碳资源化利用的研究进展,石油化工2010,39(5), 465-475. (invited by editor) [link]
  1. 刘安华,何良年*,高健,杨珍珍,李雨浓,李斌,於兵,二氧化碳化学:二氧化碳的催化转化反应,合成化学(全国第16届有机和精细化工中间体学术交流会)2010,增刊,80-91.[link]
  1. Liang-Nian He, Zhen-Zhen Yang, An-Hua Liu, Jian Gao, Sébastien Chanfreau, Green process for dimethyl carbonate synthesis starting from carbon dioxide, Prep. Pap.-Am. Chem. Soc., Div. Fuel Chem. 2010, 55 (2), 910-911.
  1. Cheng-Xia Miao,Liang-Nian He,* Jin-Quan Wang, Jian Gao, Biomimetic Oxidation of Alcohol Catalyzed by TEMPO-Functionalized Polyethylene Glycol and Copper(I) Chloride in Compressed Carbon Dioxide, Synlett2009, (20), 3291-3294. [link]

Abstract: Recyclable TEMPO-functionalized polyethylene glycol [PEG6000-(TEMPO)2] in combination with cuprous chloride were developed for biomimetic oxidation of a series of benzylic, allylic, heterocyclic alcohols and 2-phenylethanol into the corresponding aldehydes or ketones with high selectivity and moderate to high conversion in the environmentally friendly and safe medium, i.e. compressed CO2, which enhanced the catalytic activity as well as improved the selectivity.

  1. C.-X. Miao,L.-N. He,* J.-Q. Wang, J.-L.Wang, TEMPO and Carboxylic Acid Functionalized Imidazolium Salts/NaNO2: An Efficient, Reusable, Transition Metal-Free Catalytic System for Aerobic Oxidation of Alcohol, Adv. Synth. Catal., 2009, 351(13), 2209-2216. [link]

Abstract: An effective catalytic system comprising a TEMPO functionalized ionic liquid (IL-TEMPO), a carboxylic acid substituted imidazolium-based ionic liquid (IL-COOH), and NaNO2 was deveolped for aerobic oxidation of aliphatic, allylic, heterocyclic and benzylic alcohols to the respective carbonyl compounds with excellent selectivity up to >99 %, even at ambient condition. Notably, the catalyst system could preferentially oxidize a primary alcohol to the aldehyde rather than a secondary alcohol. Moreover, the reaction rate is greatly enhanced with proper amount of water present. And a high turnover number  (TON 5 000) is achieved in the present transition-metal-free aerobic catalytic system. Additionally, the functionalized ionic liquids are successfully reused at least four times. This process thus represents a greener pathway for aerobic oxidation of alcohols into carbonyl compounds by using the present task-specific ionic liquids in place of the toxic and volatile additive, such as HBr, Br2, HCl, which is commonly required for the transition-metal-free aerobic oxidation of alcohols.

  1. J.-L. Wang,L.-N. He,* C.-X. Miao, Y.-N. Li, Ethylene carbonate as a unique solvent for palladium-catalyzed Wacker oxidation using oxygen as the sole oxidant, Green Chem.2009, 11, 1317-1320. (Top 10 for November 2009)[link]

Abstract: Ethylene carbonate as a unique solvent for Wacker oxidation of higher alkenes and aryl alkenes has been successfully developed using molecule oxygen as the sole oxidant, in which the colloidal Pd nanoparticles stabilized in EC is considered to facilitate its reoxidation under cocatalyst-free conditions.

  1. J.-Q. Wang,L.-N. He,* Polyethylene Glycol radical-initiated benzylic C-H bond oxygenation in compressed carbon dioxide, New J. Chem.2009, 33(8), 1637-1640. [link]

Abstract: A new methodology to induce free radical reactions was established by the oxygenation of benzylic hydrocarbons in dense CO2. The PEG radical originating from thermal/oxidative degradation of PEG in dense CO2 was successfully applied to the oxygenation of benzylic hydrocarbons with enormous synthetic potentials under organic solvent-free conditions. In addition, the dense CO2 in our study could improve the oxygenation reaction.

  1. 何良年,王金泉,窦晓勇.离子液体与绿色化学 3.1 离子液体与二氧化碳的化学转化利用,(21世纪科学版化学专著系列,ISBN 978-7-03-024616-5)北京:科学出版社,2009年5月第一版,p.249-275. (Book review invited by editor)
  1. J.-Q. Wang,L.-N. He,* C.-X. Miao, J. Gao, The Free-Radical Chemistry of Polyethylene Glycol: Organic Reaction in Compressed Carbon Dioxide, ChemSusChem2009, 2, 755-760. (most accessed article in 02/2010)[link]

Abstract: The thermal/oxidative degradation of polyethylene glycol (PEG) is known to occur under oxygen atmosphere at elevated temperature. In conjunction with compressed CO2, PEG radical assumed to be generated from PEG thermal oxidative degradation was first successfully applied to initiate a set of free radical reactions such as selective formylation of primary and secondary aliphatic alcohols, and oxidation of benzylic alcohols, and benzylic C=C bond cleavage and benzylic sp3 C-H oxidation with enormous synthetic potentials in a practically utilizable manner with cost-efficient and environmentally friendly benefit without any additional free radical initiator nor a catalyst. We find that both PEG and molecule oxygen are prerequisite to performing those reactions smoothly. Given that dense CO2 is immune to free radical chemistry; it is an ideal solvent for such free radical reactions. As a result, compressed CO2 in this elegant study allows such reactions initiated by PEG radical able to be tuned by subtly adjusting reaction parameter like CO2 pressure, thus leading to enhancing the product selectivity. Attaining high selectivity towards the desired product makes this methodology more practical in organic synthesis.

  1. Y. Wu,L.-N. He*, Y. Du, J.-Q. Wang, C.-X. Miao, Zirconyl chloride: an efficient recyclable catalyst for  synthesis of 5-aryl-2-oxazolidinones CO2 under solvent-free conditions, Tetrahedron2009, 65(31), 6204-6210. [link]

Abstract: The cycloaddition reaction of aziridines with CO2 heterogeneously catalyzed by ZrOCl2.8H2O smoothly proceeded, leading to the preferential formation of 5-aryl-2-oxazolidinones; and excellent yields, regio- and stereoselectivities towards the target products were reached under solvent-free conditions.

  1. Jin-Quan Wang,Liang-Nian He* and Cheng-Xia Miao, Polyethylene glycol radical-initiated oxidation of benzylic alcohols in compressed carbon dioxide, Green Chem2009, 11, 1013-1017.[link]

Abstract: The PEG radical from oxidative degradation of polyethylene glycol was first used to initiate the oxidation of benzylic alcohols to carbonyl compounds without the need of a catalyst and additive in a viable synthetic, cost-effective and environmentally benign way, in which PEG/O2/CO2 acts as initiator, oxidant and solvent.

  1. Jing-Lun Wang,Liang-Nian He,* Xiao-Yong Dou, Fang Wu, Polyethylene glycol: an alternative solvent for the synthesis of cyclic carbonate from vicinal halohydrin and carbon dioxide, Aus. J. Chem., 2009, 62, 917-920. [link]
  1. L.-N. He*, J.-Q. Wang, J.-L. Wang, Carbon dioxide chemistry: examples and challenges in chemical utilization of carbon dioxide,Pure Appl. Chem2009, 81(11), 2069-2080. (invited by editor)[link]
  1. L.-N. He*, Y. Du, C.-X. Miao, J.-Q. Wang, X.-Y. Dou, Y. Wu, Methodologies for chemical utilization of CO2to valuable compounds through molecular activation by efficient catalysts, Front. Chem. Eng. China2009, 3(2), 224-228.
  1. 汪靖伦,何良年*,王金泉,杜亚,苗成霞,窦晓勇,吴颖,高健,温室气体二氧化碳化学转化与利用的方法学,精细化工中间体2009, 39 (5), 1-7. (invited by editor) [link]
  1. J.-L. Wang, J.-Q. Wang, L.-N. He,*X.-Y. Dou, F. Wu, A CO2/H2O2-tunable reaction: direct conversion of styrene into styene carbonate catalyzed by sodium phosphotungstate/n-Bu4NBr, Green Chem.2008, 10, 1218-1223.[link]

Abstract: A facile synthesis of styrene carbonate was realized directly from styrene and CO2 in an environmentally benign manner with an inorganic base as a “deprotonation reagent”, and a recyclable catalyst system, and mild reaction conditions. Selective formation of carbonate 1b and preferentially producing benzoate 1a could be controlled by subtly tuning the quantities of CO2 and H2O2.

  1. Y Du, Y Wu, A.-H. Liu, L.-N. He*, Quaternary Ammonium Bromide Functionalized- Polyethylene Glycol: A Highly Efficient and Recyclable Catalyst for Selective Synthesis of 5-Aryl Oxazolidinones from Carbon Dioxide and Aziridines Under Solvent-Free Conditions, J. Org. Chem.2008, 73(12), 4709-4712. [link]

(Selected by the Editorial Board of SYNFACTS for its important insights, SYNFACTS, Y08908SF)

Abstract: A quaternary ammonium bromide covalently bound to polyethylene glycol (PEG, MW=6000), i.e. PEG6000(NBu3Br)2 was found to be an efficient and recyclable catalyst for the cycloaddition reaction of aziridines to CO2 under mild conditions without utilization of additional organic solvents or co-catalysts. As a result, 5-aryl-2-oxazolidinone was obtained in high yield with excellent regioselectivity. The catalyst worked well for a wide variety of 1-alkyl-2-arylaziridines. Besides, the catalyst could be recovered by centrifugation and reused without significant loss of catalytic activity and selectivity.

  1. C.-X. Miao, J.-Q. Wang, L.-N. He*, Catalytic process for chemical conversion of carbon dioxide into cyclic carbonates and polycarbonates, The Open Org. Chem. J.2008, 2, 68-82. [link]

Abstract: The development of catalytic methods for chemical transformation of CO2 into useful compounds is of paramount importance from a standpoint of C1 chemistry and so-called green chemistry. The kinetic and thermodynamic stability of CO2 molecule presents significant challenges in designing efficient chemical transformations based on this potential feedstock. In this context, efforts to convert CO2 to useful chemicals will inevitably rely on its activation through molecular catalysts, particularly transition-metal catalysts. Two preparative processes employing solid catalyst or CO2-philic homogeneous catalyst were devised for environmentally benign synthesis of organic carbonates and oxazolidinones under solvent-free conditions. Those processes represent pathways for greener chemical fixations of CO2 to afford industrial useful materials such as organic carbonates and oxazolidinones with great potential applications.

  1. C.-X. Miao, J.-Q. Wang, Y. Wu, Y. Du, and L.-N. He*, Bifunctional Metal-Salen Complexes as Efficient Catalysts for the Fixation of CO2with Epoxides under Solvent-Free Conditions, ChemSusChem, 2008, 1(3), 236-241. (one most cited articles published in 2008)[link]

Abstract: A bifunctional cobalt-salen complex containing a Lewis acidic metal center and a quaternary phosphonium salt unit anchored on the ligand (Co-salen-R3P+X) was used to effectively synthesize cyclic carbonates from CO2 and epoxides under mild conditions without the utilization of additional organic solvents or co-catalysts. The effects of various reaction variables on the catalytic performance were also discussed in detail. The results indicate that the optimized reaction temperature is ca. 100 oC. The maximum appeared in the yield versus pressure curves at around 4 MPa, whereas the reaction could smoothly be operated even under the pressure as low as 2 MPa. Interestingly, the axial ligands have a great effect on the catalyst performance. In this work, the catalyst was found to be applicable to a variety of epoxides, producing the corresponding cyclic carbonates. Furthermore, the catalyst can be easily recovered and reused at least four times without significant loss of its catalytic activity. In addition, this process represents a greener pathway for the environmentally benign chemical fixation of CO2 to produce cyclic carbonate using a single-component bifunctional metal-salen complex as an effective catalyst.

  1. Y. Du, L.-N. He*, D.-L. Kong, Magnesium-catalyzed synthesis of organic carbonate from 1, 2-diol/alcohol and carbon dioxide, Catal. Commun.2008, 9(8), 1754-1758.[link]

Abstract: Low toxic magnesium and its oxide are proved to be a catalyst for highly selective synthesis of propylene carbonate (PC) through the carbonylation of propylene glycol (PG) with CO2 without any organic solvents or additives. Interestingly, the catalyst was demonstrated to be applicable to a variety of 1, 2-diols such as glycol, phenyl glycol, and methanol, forming the corresponding carbonates in 100% selectivity. As a result, employing a low toxic and cheap catalyst could make PC synthesis much environmentally friendlier. A mechanistic insight into the Sn/Mg-catalyzed reaction of “PG+CO2” was also studied herein.

  1. Y. Zhao, L.-N. He, Y. Y. Zhuang, J. Q. Wang, Dimethyl carbonate synthesis via transesterification catalyzed by quaternary ammonium salt functionalized chitosan, Chin. Chem. Lett.2008, 19(3), 286-290.[link]

Abstract: A quaternary ammonium salt covalently linked to chitosan was first used as a catalyst for dimethyl carbonate (DMC) synthesis by the transesterification of propylene carbonate (PC) and methanol. The effects of various reaction variables like reaction time, temperature and pressure on the catalytic performance were also investigated. 54% DMC yield and 71% PC conversion has been obtained under the optimal reaction conditions. Notably, the catalyst was able to be reused with retention of high catalytic activity and selectivity. Consequently, the process presented here has great potential for industrial application due to its advantages such as stability, easy preparation from renewable biopolymer, and simple separation from products.

  1. J.-S. Tian, F. Cai, J.-Q. Wang, Y. Du,L.-N. He*, Environmentally Benign Chemical Conversion of CO2 into Organic Carbonates Catalyzed by Phosphonium Salts, Phosphorus, Sulfur, and Silicon and the Related Elements2008, 183(2-3), 494-498.[link]

Abstract: Quaternary phosphonium salts were proved to be efficient homogeneous catalysts for solvent-free synthesis of cyclic carbonates from carbon dioxide and epoxides. Propylene carbonate was produced in quantitative yield and excellent selectivity. Furthermore, a PEG-supported phosphonium salt was solidified by adding ether and cooling after reaction and recovered by a simple filtration. Hence immobilization of a phosphonium salt on PEG provides an alternative pathway for realizing homogeneous catalyst recycling.

  1. H. Tang, A Lu, Z. Zhou*, P. Gao, L.-N. He*, C. Tang,Chiral tertiary amine/L-proline cocatalyzed enantioselective Morita-Baylis-Hilliman (MBH) reaction, Eur. J. Org. Chem. 2008, 126-135.[link]
  1. H. Tang, G. Zhao, Z. Zhou*, G.-F. Zhao, L.-N. He*, C. Tang,Chiral Phosphoric Acid Catalyzed Asymmetric Friedel–Crafts Alkylation of Indoles with Simple α, β-Unsaturated Aromatic Ketones,Eur. J. Org. Chem2008, 1406–1410.[link]
  1. X.-Y. Dou, J.-Q. Wang, Y. Du, E. Wang,L.-N. He*, Guanidium salt functionalized PEG: an effective and recyclable homogeneous catalyst for the synthesis of cyclic carbonates from CO2 and epoxides under solvent-free conditions, Synlett2007, (19), 3058-3062.[link]

Abstract: A guanidinium bromide covalently bound to CO2-philic polyethylene glycol is proved to be a highly effective homogeneous catalyst for the eco-friendly synthesis of cyclic carbonates from carbon dioxide and epoxides under mild conditions, which requires no additional organic solvents or co-catalyst. Notably, it has been found that there is a pronouncedly cooperative effect between the catalyst part and the support part. Moreover, the catalyst is able to be reused with retention of high catalytic activity and selectivity. This process looks promising as a strategy for homogeneous catalyst recycling.

  1. J.-S. Tian, C.-X. Miao, J.-Q. Wang, F. Cai, Y. Du, Y. Zhao andL.-N. He*, Efficient synthesis of dimethyl carbonate from methanol, propylene oxide and CO2 catalyzed by recyclable inorganic base/phosphonium halide-functionalized polyethylene glycol, Green Chem., 2007, 9, 566-571.[link]

Abstract: The cycloaddition of propylene oxide and CO2 to form propylene carbonate promoted by phosphonium salt convalently bound to polyethylene glycol (PEG), and the transesterification of propylene carbonate with methanol to DMC mediated by PEG-supported K2CO3, were separately investigated. Single supported catalyst (K2CO3/BrBu3PPEG6000PBu3Br) was shown to be active for DMC synthesis from propylene oxide, CO2 and methanol under mild reaction conditions, even under low CO2 pressure (2 bar). The catalyst was readily separated and reused without catalyst leaching detected by 31P NMR. Notably, excellent yield of DMC and complete conversion of propylene carbonate were reached under optimized reaction conditions. This procedure was also successfully applied to the synthesis of other dialkyl carbonates, and eliminates the requirement for toxic and wasteful feedstocks such as phosgene and carbon monoxide.

  1. J.-Q. Wang, F. Cai, E. Wang, L.-N. He*, Supercritical carbon dioxide and poly (ethylene glycol): an environmentally benign biphasic solvent system for aerobic oxidation of styrene,Green Chem., 2007, 9, 882-887.[link]

 

Abstract: Aerobic oxidation of styrene catalyzed by PdCl2/CuCl can be smoothly performed in the supercritical carbon dioxide and poly (ethylene glycol) biphasic system. High conversion of styrene and yield of acetophenone were obtained in the presence of a relatively low catalyst loading. This environmentally benign biphasic catalytic system can be applied to the Wacker oxidation of various alkenes. Furthermore, the PdCl2-mediated oxidation of styrene was preferentially converted into benzaldehyde using a biphasic scCO2/PEG system. The PEG could effectively immobilize and stabilize the catalysts. The present biphasic system could facilitate products separation and catalyst recycling. The effects of the reaction parameters such as solvent and COpressure were also investigated in detail.

  1. Y. Zhao, J.-S. Tian, X.-H. Qi, Z.-N. Han, Y.-Y. Zhuang andL.-N. He*, Quaternary ammonium salt-functionalized chitosan: an easily recyclable catalyst for efficient synthesis of cyclic carbonates from epoxides and carbon dioxide, J. Mol. Catal. A: Chem.2007, 271(1-2), 284-289.[link]

Abstract: A quaternary ammonium salt covalently bound to chitosan (a functionalized biopolymer) is reported as an efficient and recyclable single-component catalyst for the synthesis of propylene carbonate from propylene oxide and CO2 without any organic solvent or co-catalyst. Notably, this environmental benign and cost-effective process has great potential to be applied in various continuous flow reactors in industry.

  1. J.-Q. Wang, X.-D. Yue, F. Cai, L.-N. He*, Solventless synthesis of cyclic carbonates from carbon dioxide and epoxides catalyzed by silica-supported ionic liquids under supercritical conditions, Catal. Commun.2007, 8, 167-172.[link]

Abstract: Silica-supported quaternary ammonium salt proved to be a recyclable and efficient heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO2 under supercritical conditions, which requires no additional organic solvents either for the reaction or for the separation of product; the work-up procedure is straightforward and the catalyst could be reused without obvious loss of catalytic activity and selectivity. Moreover, this organic solvent-free process presented here could show much potential application in industry due to its simplicity, easy product separation from reaction medium and catalyst recycling. It could be profitably applied to the development of fix-bed continuous flow reactors, avoiding the use of solvent to isolate the products.

  1. H. Tang, P. Gao, G. Zhao, Z. Zhou*,L.-N. He*, C. Tang, (1R,2R)-(-)-2Dimethylamino-1-(4-nitrophenyl)-1,3-propanediol/L-Proline Cocatalyzed Enantioselective Morita-Baylis-Hillman Reaction. Catal. Commun.2007, 8, 1811-1814.[link]
  1. L.-N. He*, J.-S. Tian, C.-X. Miao, F. Cai, J.-Q. Wang, Y. Du, Poly(ethylene glycol)-supported phosphonium halides in combination with inorganic bases/PEG for highly efficient synthesis of dimethyl carbonate from methanol, propylene oxide, and CO2Preprints of Symposia – American Chemical Society,Division of Fuel Chemistry2006, 51(2), 534-535.
  1. J.-Q. Wang, D.-L. Kong, J.-Y. Chen, F. Cai, L.-N. He,*Synthesis of cyclic carbonates from epoxides and carbon dioxide over silica-supported quaternary ammonium salts under supercritical conditions, J. Mol. Catal. A: Chem.2006, 249, 143-148.[link]
  1. Y. Du, J.-Q. Wang,J.-Y. Chen, F. Cai, J.-S. Tian, D.-L. Kong, L.-N. He*, A poly(ethylene glycol)-supported quaternary ammonium salt for highly efficient and environmentally friendly chemical fixation of CO2 with epoxides under supercritical conditions, Tetrahedron Lett.2006, 47(8), 1271-1275. (Most Cited Paper 2006-2009 Award)[link]

Abstract: A PEG-supported quaternary ammonium salt is proved to be an efficient and recyclable homogeneous catalyst for solvent-free synthesis of cyclic carbonates from carbon dioxide and epoxides under supercritical conditions.

  1. J.-S. Tian, J.-Q. Wang, J.-Y. Chen J.-G. Fan, F. Cai, L.-N. He*, One-pot synthesis of dimethyl carbonate catalyzed by n-Bu4NBr/ n-Bu3N from methanol, epoxides, and supercritical CO2Appl. Catal. A: Gen.2006, 301(2), 215-221.[link]

Abstract: Dimethyl carbonate synthesis via one-pot appoarch involving two successive reactions: carbonylation of epoixde followed by transesterification was reported. The best compromise for the one-pot synthesis was achieved with an equimolar amount of tetrabutyl ammonium bromide/ tributylamine. A possible mechanism for the present n-Bu4NBr/n-Bu3N-catalyzed one-pot synthesis of DMC was proposed.This process eliminated the separation process and had environmentally benign feature.

  1. H Yasuda, L.-N. He, T. Takahashi, T. Sakakura. Non-halogen catalysts for propylene carbonate synthesis from CO2under supercritical conditions, Appl. Catal. A: Gen., 2006, 298, 177-180.[link]
  1.      Y. Du, F. Cai, D.-L. Kong, L.-N. He*, Organic Solvent-free Process for the Synthesis of Propylene Carbonate from Supercritical Carbon Dioxide and Propylene Oxide Catalyzed by Insoluble Ion Exchange Resins,Green Chem., 2005, 7(7), 518-523. (Cover Article, “Green Chemistry”杂志2005年第七期封面论文,The fifth most popular cover art of 2005, with 56 of Cited times up to 03/2010)

Abstract: The insoluble ion exchange resins, one type of polystyryl supported catalysts containing ammonium salt or amino group, and the polar macroporous adsorption resin, are efficient and reusable heterogeneous basic catalysts for the synthesis of propylene carbonate from propylene oxide and COunder supercritical CO2 conditions (373K, 8MPa), which requires no additional organic solvents either for the reaction or for the separation of product.Various reaction parameters affecting the reaction were examined. The quantitative yield (>99%) together with excellent selectivity(>99%) was obtained. The purity of product separated out directly by filtration from the reaction mixture, reached more than 99.3% without further  purification process. The catalyst can be easily recovered and reused without significant loss of its catalytic activity. The process represents a simple, ecologically safer, cost-effective route to cyclic carbonates with high product quality, as well as easy product recovery and catalyst recycle.

 

  1.    Y. Du, D.-L. Kong, H.-Y. Wang, F. Cai, J-.S. Tian, J.-Q. Wang,L.-N. He*, Sn-catalyzed synthesis of propylene carbonate from propylene glycol and CO2 under supercritical conditions, J. Mol. Catal. A: Chem.2005, 241, 233-237.[link]

Abstract: Dibutyltin oxide or dibutyltin dimethoxide was first used as a remarkable selective catalyst for the synthesis of propylene carbonate from propylene glycol and carbon dioxide. The effects of the reaction parameters such as reaction time, temperature and CO2 pressure on the amount of propylene carbonate were also experimentally studied. Under the optimized conditions, the amount of propylene carbonate was nearly proportional to PG concentration. The use of N, N-dimethylformamide as a co-solvent in this study significantly enhanced the catalytic activity, and the ketals as dehydrating agents greatly improved the yield of PC, which can be limited by the equilibrium. A postulated mechanism for the dibutyltin oxide–catalyzed carboxylation of propylene glycol was also discussed.

  1. H. Yasuda, L.-N. He, T. Sakakura, Efficient synthesis of cyclic carbonate from carbon dioxide catalyzed by poly-oxometalate: remarkable effects of metal substitution,J. Catal., 2005, 233, 119-122.[link]

2003

 

  1. L.-N. He, H. Yasuda, T. Sakakura, New procedure for recycling homogeneous catalyst: propylene carbonate synthesis under supercritical CO2Green Chem., 2003, 5(1), 92-94.
  2. H. Yasuda, L.-N. He, T. Sakakura, Cyclic carbonate synthesis from epoxide and carbon dioxide catalyzed by samarium oxychloride supported on zirconia, Stud. Surf. Sci. Catal.,2003, 136, 259-262.
  3. H. Yasuda, L.-N. He, T. Sakakura, Cyclic carbonate synthesis from supercritical carbon dioxide and epoxide over lanthanide oxychloride, J. Catal.2002, 209, 547-550.
  4. J.-C. Choi, L.-N. He, T. Sakakura, Selective and high yield synthesis of dimethyl carbonate directly from carbon dioxide and mathanol, Green Chem., 2002, 4(3), 230-234.
  5. L.-N. He, J.-C. Choi, T. Sakakura, Hydrosilation of polyfluoroolefin in dense carbon dioxide, Tetrahedron Lett., 2001, 42, 2169-2171.[link]
  6. 何良年,生物活性磷杂环化学,华中师范大学出版社:武汉,2000年.

专利

  1. 窦晓勇,何良年,叶锋.蓖麻油无酚裂解制备癸二酸的清洁生产工艺. (申请号:200810152326.0),公开号:CN 101367719 2009.
  2. 赵  元, 漆新华, 何良年, 庄源益,催化剂QCS-N的制备及用于碳酸丙烯酯的合成,中国专利申请号CN Patent 200710059622.1, to Nankai University, 2007. (公开号:CN101164696,公开日:2008.04.23).
  3. 赵  元, 漆新华, 何良年, 庄源益,制备碳酸二甲酯的新工艺及其催化剂与制备,中国专利申请号CN Patent 200710059728.1, to Nankai University, 2007. (公开号:CN101121147,公开日:2008. 02.13)
  4. 何良年杜亚,蔡飞,张红学高分子负载的非均相催化剂制备环状碳酸酯的方法,中国专利号ZL 200410093952.9,(公开CN1680360A, 2005-10-12).
  5. Preparation of cyclic carbonate with polystyrene-type catalysis.9 pp.  CN  1680360 A  20051012  CAN 145:29881  AN 2006:498529.
  6. 何良年,田杰生,苗成霞,蔡飞,杜亚,王金泉,张洪学.可循环使用的功能化聚乙二醇催化制备环状碳酸酯的方法,中国专利ZL 200610014909.8(公开号:CN101003531,2007.07.25).
  7. Preparation of alkylene carbonates and substituted heteropoly acid salt catalysts for the processJpn. Kokai Tokkyo Koho JP 2004250349 (2004).
  8. Process for preparation of cyclic carbonates, WO 2005085224 (2005).

发表在中文刊物上的论文

  1. 赵  元, 漆新华, 何良年, 庄源益,季铵化壳聚糖催化环氧丙烷和二氧化碳合成碳酸丙烯酯,石油化工, 2007,36,1148-1149
  2. 蔡飞, 王金泉,张洪学,何良年, 兽药中间体氟尼辛的高效液相色谱分析,精细化工中间体,2007,37(5),67-69.
  3. 赵 元, 汪 二, 漆新华, 何良年, 超临界二氧化碳介质中的烃类氧化反应,精细化工中间体,2007,37(2),1-5.
  4. 岳晓东,何良年.超临界二氧化碳参与的两相体系及其在有机合成反应中的应用, 有机化学,2006,26, 610-617.
  5. 田杰生,王金泉,杜亚,何良年.二氧化碳与环氧化物的共聚反应,化学进展, 2006, 18(1), 74-79.
  6. 何良年杜亚,王金泉,等,二氧化碳的资源化利用及超临界二氧化碳中的化学反应,有机化学,2005, 25(Suppl1):157.
  7. 王金泉,田杰生,杜亚,何良年. 超临界二氧化碳介质中的酶催化反应, 化学通报, 2005,68(8),w087(1-7).
  8. 杜亚,王金泉,田杰生,何良年.超临界二氧化碳中气体参与的有机化学反应, 精细化工中间体,2005,35(1), 1-7.
  9. 岳晓东,何良年.聚碳酸酯的绿色工艺研究进展, 化学研究,2005, 16,94-98.
  10. 何良年. 碳酸二甲酯在农药与医药合成工艺绿色化中的应用,华中师范大学学报(自然科学版)2005,39(4),495-499.
  11. 孔德林,蔡飞,何良年.以可再生资源二氧化碳为原料合成环状碳酸酯,精细化工中间体,2005,35(6),1-5.(被评为2005年《精细化工中间体》优秀论文)

2002以前发表的论文 

  1. L. He, Y. Luo,K. Li, G. Yang, M. Ding, X. Liu, T. Wu, A facile synthesis of fused phosphorus-heterocycle with bioactivity via Lawesson’s Reagent, Phosphorus, Sulfur, and Silicon and the Related Elements, 2002, 177, 2675-2678.
  2. L. He, Y. Luo, K. Li, M. Ding,A. Lu, X. Liu, T. Wu, F. Cai, A Novel Route to spiro phosphorus- heterocycle via Lawesson’s Reagent, Synth. Commun., 2002, 33(9), 1415-1419.
  3. Y. Luo,L. He, M. Ding, G. Yang, A. Lu, X. Liu, T. Wu, A Convenient synthesis of derivatives of 1,3,2-dioxaphosphocane-2-sulfide with bioactivity via Lawesson’s Reagent, Heterocyclic Commun.,2001, 7(1), 37-42.
  4. L. He, Y. Luo,M. Ding, A. Lu, X. Liu, T. Wu, F. Cai, Synthesis of derivatives of 1,3,2-diazaphospholidin- 4-ones and the corresponding 2-sulfides, Heteroatom Chem., 2001, 12(6), 497-500.
  5. L.-N. He, K. Li, X.-P. Liu, Y.-P. Luo, A.-H. Lu,M.-W. Ding, Synthesis of 1,3-diaryl-1,3,2- diazaphosholidin- 4-thione-2-sulfides via Lawesson’s reagent, Phosphorus, Sulfur, and Silicon and the Related Elements2000, 158, 117-123.
  6. L.-N. He, K. Li, Y.-P. Luo, X.-P. Liu, M.-W. Ding, Q.-C. Zhou, T.-J. Wu, F. Cai, A facile synthesis of derivatives of 4-aryl-1,3,2-dioxaphoshorinane-2-sulfide via Lawesson’s reagent, Phosphorus, Sulfur, and Silicon and the Related Elements,2000, 156, 173-179.
  7. L.-N. He, R.-X., Zhuo, R.-Y. Chen, Y.-J. Zhang, Synthesis of biologically active phosphorus heterocycles via Lawesson’s reagent, Heteroatom Chem.1999, 10(2), 105-111.
  8. K. Li, L.-N. He, X.-H. Qing , Y.-P. Luo, M.-W. Ding, A Facile synthesis of 1-alkyl-1,3,2- diazaphospholidin-4-thione-2-sulfide via Lawesson’s Reagent. Heterocycl. Commun., 1999,  5(2), 189-192.
  9. L.-N. He,B. Feng, T.-B. Huang, Q.-C. Zhou, J.-L. Zhang, Synthesis of new 1,3-benzothiazole-2-phosphoric hydrazides. Phosphorus, Sulfur, and Silicon and the Related Elements, 1999, 148, 51-60.
  10. L.-N. He, M.-W. Ding, S.-B. Li, Q.-C. Zhou, Y.-P. Luo, T.-J. Wu, X.-P. Liu, F. Cai, Synthesis of insecticidal activity of O-aryl-(1,2,2,2-tetrachloroethyl) phosphoramidothioates and their thiophosphoric hydrazides, Heteroatom Chem., 1999,10(6) 441-445.
  11. L.-N. He, R.-X. Zhuo, K. Li, X.-P. Liu, Application of Lawesson’s reagent in syntheses of biologically active phosphorus heterocycles. Phosphorus, Sulfur, and Silicon and the Related Elements,1999, 147, 111.
  12. L.-N. He, R.-X. Zhuo, X.-P. Liu, F. Cai, The quantitative structure-herbicidal activity relationship of 1-aryl-1,3,2-diazaphospholidin-4-thione-2-sulfides. Phosphorus, Sulfur, and Silicon and the Related Elements, 1999, 144-146, 453-456.
  13. L.-N. He, T.-B. Huang, F. Cai, R.-Y. Chen, Studies on reaction of Lawesson’s reagent with phenylthiourea   and oxamide, Phosphorus, Sulfur, and Silicon and the Related Elements1998, 132,147-152.
  14. L.-N. He, K. Li, X.-P. Liu, et al, A convenient route to 3H-benzo[f]-1,3,4,2 oxadiazaphosphosphepin-2-sulfide via Lawesson’s reagent Heterocycl. Commun.1998, 4(5), 451-454.
  15. L.-N. He, R.-Y. Chen, et al. Simple route to phospholane from 2-mercapto-1,3,4-oxadiazole and 3-mercapto- 1,3,4-triazole, Heterocycl. Commun.1997, 3(5), 461–463.
  16. L.-N. He, R.-X. Zhuo, R.-Y. Chen, J. Zhou, A new route to cyclic phospholipid analogues via cyclization of Lawesson’s reagent with long-chain 1-glyceryl ethers Synth. Commun., 1997, 27 (16), 2853-2856.
  17. L.-N. He, R.-Y. Chen, The reaction of Lawesson’s reagent with glycinamide, synthesis and herbicidal activity of 1,3,2-diazahospholidin-4-thione-2-sulfide, Phosphorus, Sulfur, and Silicon and the Related Elements1997, 129, 111-120.
  18. L.-N. He, F. Cai, R.-Y. Chen, J. Zhou, Synthesis of 1,4-diphenyl-1,3,2-diazaphospholidin-5-one-2- oxides and their structure-herbicidal activity relationship, Phosphorus, Sulfur, and Silicon and the Related Elements,1997, 130, 65-71.

 

Publications in domestic journals

  1. Y. LuoF. Zheng, L. He, New method for the preparation of Japanese reagent,Huaxue Shiji2001, 23(5), 314.
  2. Y. Luo, L. He, Japanesereagent –new building blocks in synthetic chemistry, Hecheng Huaxue2001, 9(1), 34-36.
  3. Y. Luo, L. He, K. Li, Progress in the research of monocoordinate organophosphorus compounds,Huaxue Shiji2000, 22(5), 289-290.
  4. L.-N. He, K. Li, R.-X. Zhuo, et al. Cyclization reaction of Lawesson’s reagent with bifunctional group containing mobile hydrogen. Acta Chimica Sinica(in Chinese), 1999, 57(9), 1026-1033.
  5. He, Liangnian; Cai, Fei; Li, Kai. Cyclization of Lawesson’s reagent with carbonyl compounds and their derivatives. Huaxue Shiji1999,21(1), 22-25(Chinese).
  6. He, Liang-Nian; Chen, Ru-Yu; Zhou, Ren-Xi. Studies on organophosphorus heterocycles. VIII. cyclization of Lawesson’s reagent with bifunctional substrates containing two amino groups. Gaodeng Xuexiao Huaxue Xuebao1997, 18(12), 1969-1973 (Chinese).
  7. He, Liangnian; Cai, Fei; Chen, Ruyu. Development of tricoordinated pentavalent phosphorus compounds with the structure of R-P(:X)(:Y)., Huaxue Tongbao,1997, (4), 6-12 (Chinese).
  8. He, Liangnian; Chen, Ruyu; Cai, Fei. Structure and chemical properties of tricoordinated pentavalent phosphorus compounds [R-P(:X)(:Y)]. Hecheng Huaxue1997, 5(4), 338-343 (Chinese).
  9. Chen, Ru-Yu; He Liang-Nian; Yang, Hua-Zheng; Yang, Xiu-Feng; Wang, Hui-Lin. Quantitative structure-activity relationship study of herbicidal 1,4,2-diazaphospholidin-5(thi)one-2-oxides. Gaodeng Xuexiao Huaxue Xuebao, 18(5), 1997, 726-729 (Chinese).
  10. He, Liang Nian; Cai, Fei; Qin, Xiang Hua; Li, Kai. The cyclization reactions of Lawesson’s reagent with bifunctional substrates. ChinChem. Lett.1997, 8(9), 751-754 (English) .
  11. He, Liang Nian; Zhuo, Ren Xi, The cycloaddition reaction of Lawesson’s reagent with 1,3-dienes. Chin. Chem. Lett., 1997, 8(8), 655-656 (English).
  12. Li, Sheng-Biao; Huang, Shi-Qiang; He, Liang-Nian; Huang, Tian-Bao; Zhou, Qin-Chung; Wang, Xiang-Lin. Synthesis, intramolecular cyclization and nematocidity of O-polyhaloalkyl-O-substituted-phenylthiophosphoric hydrazides. Youji Huaxue1997, 17(4), 374-377 (Chinese).
  13. He, Liang-Nian; Chen, Ru-Yu; Wang, Hong-Gen; Yao, Xin-Kan. Crystal structure of N-phenyl P-(4-methoxyphenylisothiocyanatidophosphonamidothioate. Jiegou Huaxue1997, 16(3), 200-202 (English)
  14. He, Liang-Nian; Chen, Ru-Yu; Zhou, Jia; Wang, Hong-Gen; Yao, Xin-Kan. Synthesis and crystal structure of 1-(o-methylphenyl) -2-(p-methoxyphenyl)- 1,3,2-diazaphospholidine-4-thione 2-sulfide. Jiegou Huaxue1997, 16(3), 215-218 (English).
  15. Chen, Ru-Yu; He, Liang-Nian; Yang, Xiu-Feng. Synthesis and herbicidal activity of1-(p-toluensulfonyl)- 2-phenoxy-3-aryl-1,4,2-diazaphospholidin-5-thione-2-oxides. Gaodeng Xuexiao Huaxue Xuebao1996, 17(12), 1865-1868 (Chinese).
  16. He, Liangnian; Luo, Guangfu; Cai, Fei; Zhang, Jingling. Synthesis of O-(1,2,2,2-tetrachloroethyl) phosphorothioic dichloride through PCl3 route,  Jingxi Huagong1997, 14(5), 30-33 (Chinese).
  17. He, Liangnian; Chen, Ruyu; Yang, Xiufeng. Study on synthesis and herbicidal activity of 1,4-diphenyl- 2-phenoxy-1,4,2-diazaphospholidin-5-one-2-oxides, Hecheng Huaxue1997, 5(1), 57-60 (Chinese)
  18. He, Liangnian; Cai, Fei; Zhang, Jingling. Preparation of O-(1,2,2,2-tetrachloroethyl) phosphorothioic dichloride and chloride. Jingxi Huagong1997, 14(4), 60-62 (Chinese).
  19. Li, Shengbiao; Huang, Shiqiang; He, Liangnian; Huang, Tianbao; Zhou, Qingchun; Zhang, Jinling. Synthesis, characterization and biological activity of O-(1,2,2,2-tetrachloro)ethy l- O-substituted-phenyl-phosphoramidothionates. Yingyong Huaxue1997, 14(2), 45-49 (Chinese).
  20. Chen, Ru-Yu; He, Liang-Nian; Yang, Xiu-Feng. Synthesis and herbicidal activity of 1-(p-toluenesulfonyl)- 2-phenoxy-3-alkyl-4-phenyl-1, 4-diazaphospholidin-5-one-2-oxides, Gaodeng Xuexiao Huaxue Xuebao1997, 18(2), 254-256 (Chinese).
  21. Chen, Ruyu; He, Liangnian; Yang, Xiufeng. Synthesis and herbicidal activity of 1-(p-toluenesulfonyl)-2-phenoxy-3-aryl-4-phenyl- 1,4,2-diazaphospholidin-5-one-2-oxides. Yingyong Huaxue1996,13(5), 29-32(Chinese).
  22. Yang, Wenqian; Huang, Tianbao; Liu, Lingfei; He, LiangNian; Zhang, Jingling, Synthesis of diphenylalkylphosphine-boranes., Gaodeng Xuexiao Huaxue Xuebao,1996, 17(7), 1083-1085 (Chinese)
  23. He, Liangnian; Li, Shengbiao; Zhang, Jinglin. Synthesis of N-alkyl-O-alkyl-O- (1-cyano-2,2,2- trichloroethyl)phosphoramidothioates. Youji Huaxue1994, 14(2), 210-14 (Chinese).