Process for carboxylation of naphthoic acid to naphthalene dicarboxylic acid

Abstract

Disclosed is a method for selective carboxylation of naphthoic acid, or other aromatic mono-acids to form primarily 2,3-naphthalene dicarboxylic acid (2,3-NDA) or other aromatic diacids which comprises reacting said aromatic mono-acid in the presence of one or more metal oxide catalysts, alone, or in combination, and in the presence of about 0.2 to 0.8 moles excess of base over aromatic mono-acid, at a temperature of about 380° C. to about 420° C., and, in a second step, disproportionating the product of said selective carboxylation at a temperature above about 420° C. to form a product with a greatly improved yield of 2,6-naphthalene dicarboxylic acid, or other aromatic dicarboxylic acid.

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