Aromatic nuclear chlorination by copper(II) chloride

Abstract

Reactive phenols are chlorinated by copper(II) chloride in a toluene suspension, and in aqueous solution. In water the reaction is markedly accelerated by aluminium, chromium, and vanadyl chlorides, and by hydrogen chloride. Concentrated hydrochloric acid is the preferred medium for the reaction; in the presence of oxygen, copper(II) chloride is regenerated continuously. The p-chloro-derivatives of phenol, m-xylenol, and o-cresol are obtained in 90% yield.

Aromatic amines are similarly chlorinated preferentially at the para-position by copper(II) chloride, but reaction with anthracene gives anthraquinone.