Patent ID: 7777072

Claim:
A process for preparing a 2,5-dialkoxyterephthalic 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 an amine 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, when it is a tetraamine, at least one primary or secondary amino group; (c) optionally, separating the dibasic salt of 2,5-dihydroxyterephthalic acid from the reaction mixture in which it is formed; (d) contacting the dibasic salt of 2,5-dihydroxyterephthalic acid with acid to form therefrom 2,5-dihydroxyterephthalic acid; and (e) converting the 2,5-dihydroxyterephthalic acid to a 2,5-dialkoxyterephthalic acid.