Green synthesis of ionic liquids for green chemistry

An environmentally friendly ("green") method for synthesis of ionic liquids has been developed. A number of useful ionic liquids have been prepared in large scale in a solvent-free and waste-free manner and in one reaction vessel, where halide-based ionic liquids were converted to non-halide-based ionic liquids in the presence of Bronsted acids and primary alcohols (ethanol, 1-propanol, 1-butanol). The alkyl halides can be recovered and reused. This novel, innovative technology eliminates the shortcomings in the previously widely used methods of making ionic liquids via the anion metathesis approaches which employ conventional organic solvents, generate aqueous and solid wastes and have a technical difficulty in industrial scale-up. The utilization of such a novel synthetic method for ionic liquids should facilitate further development of green chemistry and green chemical technologies.