Developing principles for predicting ionic liquid effects on reaction outcome: A demonstration using a simple condensation reaction

The effects of a series of ionic liquids, with systematic variations in the cation, on the condensation of an alkyl amine with an aromatic aldehyde were investigated, and the outcomes compared with those predicted based on related reactions. The addition of ionic liquids increased the observed rate constant; the mole fraction dependence of this increase was qualitatively consistent with predictions. Temperature-dependent kinetic analyses were used to demonstrate that the microscopic origins of the effects were as forecast, though the relative weighting of enthalpic and entropic contributions was dependent on the salt used.