On the rational design of microwave-actuated organic reactions

Abstract

Microwave-actuated organic reactions are defined herein as chemical reaction systems for which microwave irradiation provides a clear benefit over conventional heating to the same temperature. This study is focused on a rationally designed, microwave-actuated reaction (thermal Friedel–Crafts benzylation), in which a microwave-absorbing ionic solute reacts in a non-polar and largely microwave-transparent solvent. Steady-state microwave irradiation (ssMWi) induces observed levels of reactivity from the solute that cannot be duplicated by conventional heating of the homogeneous solution to similar temperatures. This observation is qualitatively consistent with the Arrhenius [k = Ae(−Ea/RT)] relationship between rate and molecular collisions (k ∝ A at constant T). A new paradigm for designing microwave-actuated organic reactions for microwave-assisted organic synthesis emerges from this study.