Patent ID: 6441224
Filing Date: 2002-08-27
Classification: B01J,C07C,C08G

Abstract:
A two step process for increasing the yield of a desired aromatic dicarboxylic acid which comprises:a) selectively carboxylating an aromatic mono-acid by the steps of: mixing an aromatic monoacid with excess base to form a solid salt; drying said salt; and reacting said salt in the presence of a catalyst selected from an oxide of a metal of Group IB, IIB, or IIIA of the Periodic Table at a temperature above about 350Â° C. to produce an intermediate containing an isomer of the desired aromatic dicarboxylic acid, the isomer containing a carboxyl group contributed by the base; and subsequently b) reacting said intermediate in the presence of a disproportionation catalyst at a temperature above about 420Â° C. to form the desired aromatic dicarboxylic acid.