Patent ID: 7585999

Claim:
A process for preparing 2,5-alkoxyterephthalic 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 a diketone described generally by Formula IV wherein A is R 1 and R 2 are each independently selected from substituted and unsubstituted C 1 -C 16 n-alkyl, iso-alkyl and tertiary alkyl groups; and substituted and unsubstituted C 6 -C 30 aryl and heteroaryl groups; R 3 is selected from H; substituted and unsubstituted C 1 -C 16 n-alkyl, iso-alkyl and tertiary alkyl groups; substituted and unsubstituted C 6 -C 30 aryl and heteroaryl groups; and a halogen; R 4 , R 5 , R 6 and R 7 are each independently H or a substituted or unsubstituted C 1 -C 16 n-alkyl, iso-alkyl or tertiary alkyl group; and n=0 or 1; (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.