Patent ID: 7339076

Claim:
A process for preparing 2,5-dihydroxyterephthalic acid comprising the steps of: (a) contacting a 2,5-dihaloterephthalic acid, as described generally by Formula III wherein X=Cl, Br, or I, with base in water to form therefrom the corresponding dibasic salt of the 2,5-dihaloterephthalic acid; (b) contacting the dibasic salt of the 2,5-dihaloterephthalic acid with base in water, and with a copper source in the presence of a ligand that coordinates to copper, to form the dibasic salt of 2,5-dihydroxyterephthalic acid from the dibasic salt of 2,5-dihaloterephthalic acid at a solution pH of at least about 8; wherein the ligand comprises an amino acid in which the amine nitrogen and the carboxyl carbon are separated by no more than two carbon atoms; (c) optionally, separating the dibasic salt of 2,5-dihydroxyterephthalic acid from the reaction mixture in which it is formed; and (d) contacting the dibasic salt of 2,5-dihydroxyterephthalic acid with acid to form therefrom 2,5-dihydroxyterephthalic acid.