Ionic liquids have been advanced as alternative solvents for organic reactions. In this paper, the principal findings of studies on nucleophilic substitutions in ionic liquids are reviewed. Thus our examination of halides (Cl-, Br- and I) in a range of ionic liquids is combined with our study of amine nucleophilicity into a single narrative. There have been a few other quantitative studies of nucleophilic substitutions in ionic liquids, and the results of these studies are also summarised in this work. These data are compared to related reactions in molecular solvents, and used to show where ionic liquids do (and do not) offer advantages over molecular solvents for nucleophilic substitutions.
