Process for preparing 2,6-naphthalenedicarboxylic acid

Abstract

A process for producing 2,6-naphthalenedicarboxylic acid by the liquid phase, exothermic oxidation of 2,6-dimethylnaphthalene comprising adding to a reaction zone oxidation reaction components comprising 2,6-dimethylnaphthalene, a source of molecular oxygen, a solvent comprising an aliphatic monocarboxylic acid, and a catalyst comprising cobalt, manganese and bromine components wherein the atom ratio of cobalt to manganese is at least about 1:1 and the total of cobalt and manganese, calculated as elemental cobalt and elemental manganese added to the reaction zone, is less than about 0.40 weight percent based on the weight of the solvent added to the reaction zone; maintaining the contents of the reaction zone at a temperature and pressure sufficient to cause the oxidation of 2,6-dimethylnaphthalene to 2,6-naphthalenedicarboxylic acid and the vaporization of at least a portion of the reaction solvent while maintaining a liquid phase reaction mixture; condensing the vaporized solvent and returning an amount of the condensed solvent to the reaction zone to maintain the amount of water in the reaction zone at no more than about 15 weight percent based on the weight of solvent in the reaction zone; and withdrawing from the reaction zone a mixture comprising 2,6-naphthalenedicarboxylic acid.