Solid state redox chemistry of hydroquinones and quinones

Abstract

Solid state ceric ammonium nitrate (CAN) oxidation of hydroquinones to the corresponding quinones, gives best results when operating with ultrasonic irradiation. Nitrogen dioxide plays a key role in these “solid-solid” oxidations. The oxidation of hydroquinones to quinones can also be achieved in a unique “solid-solid-solid” reaction, i.e., by using a limited amount of CAN in the presence of a full equivalent of a solid cooxidant such as KBrO 3. Reduction of quinones with sodium dithionite in the solid state gives rise to the corresponding highly colored quinhydrones and, eventually, to hydroquinones.