Patent ID: 6235949
Filing Date: 2001-05-22
Classification: C07B,C07C

Abstract:
A process for the preparation of an aryl halide compound by attaching a halogen atom directly to the aromatic ring comprising the step of:contacting a gaseous mixture containing a hydrohalic acid and at least one substrate compound selected from the group consisting of an aryl halogen formate, an aryl carbonate and an aryl compound having a radical of the formula--O--CY--Awherein Y represents a chalcogen or two halogen atoms and A represents a halogen and wherein said substrate compound has no greater than 50 carbon atoms,with a Lewis acid catalyst at a temperature of at least between about 200.degree. C. and about 800.degree. C. for a contact time Tf of between about 10.sup.-3 and 100 g.times.s/cm.sup.3, said contact time being sufficient to obtain said aryl halide having a halogen atom bonded directly to the aromatic ring, wherein the ratio of hydrohalic acid to substrate compound is in excess of the stoichiometric quantity required to effect complete halogen exchange but not less than 5.