Direct nucleophilic substitution reaction of alcohols mediated by a zinc-based ionic liquid

Abstract

A zinc-based ionic liquid ([CHCl][ZnCl₂]₂) was found to be an excellent reaction medium for the direct nucleophilic substitution reactions of alcohols. The high conversion, high selectivity, easy separation procedure, catalyst reusability and no necessity of excessive nucleophiles make the chemical process cleaner. This reaction was believed to work through the carbocation mechanism and the existence of carbocation was detected by UV-vis spectroscopy. It was suggested that the hydroxyl group on the choline cation was the major inducement for the formation of special microstructures which could provide adequate stability for the carbocation in the reaction systems and increase the reactivity and selectivity.