The effect of the structure of the anion of an ionic liquid on the rate of reaction at a phosphorus centre

Abstract

Abstract The effects of a series of 1‐butyl‐3‐methylimidazolium based ionic liquids containing different anions on the reaction of ethanol‐ d 6 with diethyl chlorophosphate were investigated. Addition of each of the salts considered resulted in an increase in the rate constant; the extent of this increase was dependent on the proportion of the ionic liquid in the reaction mixture. In contrast to previous studies, the ionic liquid effects continued to change at high proportions of these salts in the reaction mixture. Temperature‐dependent kinetic analyses were used to determine the microscopic origins of the rate constant enhancement. Correlations between the activation parameters and the coordinating ability of the anion of the ionic liquid (as measured using the Kamlet‐Taft β N parameter) suggest an additional interaction to those discussed previously. Importantly, these correlations suggest the opportunity for quantification of potential ionic liquid solvent effects in these systems.