Effect of ionic liquids on the Menschutkin reaction: an experimental and theoretical study

The effect of ionic liquids (ILs) on the Menschutkin reaction between N-methylimidazole and benzyl halides has been investigated. Hammett correlations have been used to obtain information on the reaction mechanism of benzyl chlorides in ionic and molecular solvents. The solvent effects on this reaction have been examined using both multiparameter linear solvation energy relationships and theoretical calculations. These latter have been performed using a supermolecular approach, i.e., the IL is represented by an explicit ionic pair, IP. Two possible different reaction pathways have been obtained changing the position of the IL-IP with respect to the reagents. It is hypothesized that inside the IL the Menschutkin reaction of benzyl chloride with N-methylimidazole can follow different reaction pathways by considering the influence of dynamic heterogeneity in ionic media on the time scale of the lifetime of a transition state.