Choline based ionic liquids and their applications in organic transformation

Chemical researchers always have a thrust of finding something new-which should have better impact on the environment of the planet, health of the living being and the safety of all. This finding and addition of new classes of solvents for the chemical reactions and processes is being done by chemical researchers. One such class includes the ionic liquids (ILs) which has become more popular in the recent years. The number of research publications were added day by day worldwide, which includes the use of imidazolium based ionic liquids. Although this class of ionic liquids has some shortcomings of traditional organic solvents, they exhibit adverse impact on the environment as they are non-biodegradable and toxic to the environment as well as the aquatic eco system. The choline chloride (ChCI) based ionic liquids and deep eutectic solvents have emerged as an efficient replacement for imidazole based ionic liquids and has opened up numerous opportunities owing to their non-toxic, biocompatible nature, easy accessibility and cost-effectiveness properties. Variety of choline based ionic liquids and their applications in various fields are being reported nowadays. In this study, we review (A) introduction and background of the ionic liquid (B) choline as cation for ionic liquids (C) data of the choline based ionic liquids reported data till date (D) choline based ionic liquids in the organic synthesis and polymerization reactions, (E) some miscellaneous applications such as ionic liquids in CO2, NH3 absorption, biomass conversion to speciality chemicals, dye degradation. The contents undoubtedly point out that the task specific ionic liquids possess several important properties. Recently, the ionic liquids have also been explored as template for metal ion extraction, electrolytes for lithium ion batteries and dye sensitized solar cells. In short, these ionic liquids are the future solvents of the chemical and allied industry of being their greenness property. (C) 2016 Elsevier B.V. All rights reserved.