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[email protected] Current Organic Chemistry, 2015, 19, 455-468
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Synthesis and Applications of Ionic Liquids in Clean Energy and Environment: A Review Feng Guo1, Suojiang Zhang3, Jianji Wang4, Botao Teng 1, Tengyan Zhang5 and Maohong Fan1,2* 1
Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, WY 82071, USA; 2School of Energy Resources, University of Wyoming, Laramie, WY 82071, USA; 3Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; 4School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007, China; 5Western Research Institute, Laramie, WY 82072, USA Abstract: Ionic liquids (ILS) are typically referred to as “green” or “designer” solvents. These solvents consist entirely of ionic species exhibiting many fascinating properties, such as non-flammability, low vapour pressure, wide electrochemical window and thermodynamic kinetic stability. Moreover, these remarkable properties can also be adjusted by using various synthesis methods. The application of ILs solves many major problems in green energy production and environment including solar energy, biomass and CO2 adsorption. Although, given our current state of knowledge, the applications of ILs are unpredictable; they have nonetheless rapidly attracted enormous attention in the fields of modern physical chemistry, materials science, applied technologies and engineering. This review focuses on the basic ILs synthesis methods and the latest advancements in the clean energy and environmental application of ILs.
Keywords: Application to energy, application to environment, ionic liquids, synthesis. 1. INTRODUCTION Ionic liquids (ILs) are salts with low melting points with a combination of a bulky organic cation and either an organic or inorganic anion [1-5]. Compared with the conventional salts, plenty ILs are liquid at room temperature. Therefore, in terms of melting points, ILs generally may be divided into two major categories, viz. room temperature ILs and low temperature ILs (i.e., below 130K) [3]. Furthermore, ILs may also be classified based on other physicochemical properties, components or structures, including switchable ILs [6]. Their physical properties can be switched through the addition or removal of molecular triggers, protic ILs, task-specific ILs, metal-based ILs, and chiral ILs. For instance, directly mixing a metal chloride with an organic chloride salt ([Cnmim]Cl) could be used to synthesize chlorometallate ILs with very interesting and potentially useful properties [7]. Admittedly, ILs are considered as extraordinarily green solvents due to their exclusive physicochemical properties such as their low combustibility, negligible vapour pressure, high thermal stability, phase transition behaviour (Tg
