How do microwaves heat a reaction?
Microwaves are a form of electromagnetic radiation and they heat substances that are polar and/or ionic in nature. Like all electromagnetic radiation, microwave radiation can be divided into two components, one electric field and one magnetic field component. The electric field component is responsible for the heating. This component affects heating via two major mechanisms – dipolar polarization and ionic conduction. Dipolar polarization mechanism – A dipole is sensitive to electric fields and will attempt to align itself with the field. The applied field provides the energy for this rotation. “The right frequency” of the applied irradiation is when the dipoles have time to respond to the alternating electric field and therefore rotate, but the rotation does not precisely follow the field. This gives rise to a phase difference. This phase difference causes energy to be lost from the dipole, by molecular friction and random collisions, giving rise to dielectric heating. Ionic conductio
