Acta Phys. -Chim. Sin. ›› 2021, Vol. 37 ›› Issue (5): 2010022.doi: 10.3866/PKU.WHXB202010022

Special Issue: CO2 Reduction

• REVIEW • Previous Articles     Next Articles

Recent Progress on Ionic Liquid-Mediated CO2 Conversion

Huan Wang1,2, Yunyan Wu1,2, Yanfei Zhao1,2, Zhimin Liu1,2,3,*()   

  1. 1 Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid and Interface and Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
    3 Physical Science Laboratory, Huairou National Comprehensive Science Center, Beijing 101400, China
  • Received:2020-10-12 Accepted:2020-10-30 Published:2020-11-04
  • Contact: Zhimin Liu E-mail:liuzm@iccas.ac.cn
  • About author:Zhimin Liu. Email: liuzm@iccas.ac.cn. Tel.: +86-10-62562852
  • Supported by:
    National Natural Science Foundation of China(21890761);National Natural Science Foundation of China(21533011);Beijing Municipal Science & Technology Commission, China(Z191100007219009)

Abstract:

The efficient utilization of carbon dioxide (CO2) as a C1 feedstock is of great significance for green and sustainable development. Therefore, the efficient chemical conversion of CO2 into value-added products has recently attracted a lot of research attention in recent years. The transformation of CO2 generally requires high-energy substrates, specific catalysts, and harsh reaction conditions due to its high thermodynamic stability and kinetic inertness. Consequently, several efforts have been dedicated toward the development of high-performance catalysts and new reaction routes for CO2 conversion over the last few decades. To date, many routes of convert CO2 into value-added chemicals have been proposed, together with the development of heterogeneous and homogeneous catalysts. Among the advanced catalysts reported to date, ionic liquids (ILs) have been widely investigated and show great potential for the efficient, selective, and economical conversion of CO2 into highly valuable products under mild conditions, even under ambient conditions. Some task-specific ILs have been designed with unique functional groups (e.g., —OH, —SO3H, —NH2, —COOH, and —C≡N), which can act as the solvent, absorbent, activating agent, catalyst, or cocatalyst to realize the transformation of CO2 under metal-free and mild conditions. In addition, a variety of catalytic systems composed of ILs and metal catalysts have also been reported for the transformation of CO2, in which the combination of the IL and metal catalyst is responsible for CO2 conversion with high efficiency. In this review article, we summarize the recent advances in IL-mediated CO2 transformation into chemicals prepared via C—O, C—N, C—S, C—H, and C—C bond forming processes. ILs that can chemically capture CO2 with high capacity are first introduced, which can activate CO2 via the formation of IL-based carbonates or carbamates, thus realizing the transformation of CO2 under metal-free and mild conditions. Recent progress in IL-mediated CO2 transformations to form carbonates and various kinds of N- and S-containing compounds (e.g., oxazolidinones, ureas, benzimidazolones, formamides, methylamines, benzothiazoles, and other chemicals) as well as CO2 hydrogenation to give formic acid, methane, acetic acid, low-carbon alcohols, and hydrocarbons has been summarized in this review with a focus on the reaction routes, catalytic systems, and reaction mechanism. In these reactions, ILs can simultaneously activate the substrate via strong H-bonding in addition to activating CO2, and the cooperative effects among the ionic and molecular species and metal catalysts accomplish the reactions of CO2 with various kinds of substrates to afford a wide range of value-added chemicals. Finally, the shortcomings and perspectives of ILs are discussed. In short, IL-mediated CO2 transformations provide green and effective routes for the synthesis of high-value chemicals, which may have great potential for a wide range of applications.

Key words: CO2, Ionic liquid, Conversion, Catalysis, Value-added chemicals

MSC2000: 

  • O643