Use of microwave heating to speed organic reactions continues to grow

Abstract

Microwave heating of laboratoryscale organic reaction mixtures is moving into both the undergraduate laboratory and industrial production. In the chemistry lab, heating reaction mixtures for a few minutes in a conventional oven can sometimes replace long reflux times that take up so much laboratory time. And some chemical producers are developing processes that take advantage of the clean heating and the instant on-off features of ovens. Despite these promising applications, however, the question lingers whether microwaves excel in organic reactions simply by heating faster and hotter, or whether there is some unique microwave effect. Microwave radiation is the range of the electromagnetic spectrum between radiofrequency on the low end and infrared on the high-frequency end. The arbitrary cutoffs are 300 MHz to 30 gigahertz, or 1-meter to 1-cm wavelength. The world's telecommunications agencies have commandeered most of the spectrum for radar and telecommunications. Authori...