Patent ID: 7358391

Claim:
A process for preparing a hydroxy aromatic acid that is described generally by the structure of Formula I (COOH) m —Ar—(OH) n I wherein Ar is a C 6 ˜C 20 arylene radical, n and m are each independently a nonzero value, and n+m is less than or equal to 8, comprising the steps of (a) contacting a halogenated aromatic acid that is described generally by the structure of Formula II, (COOH) m —Ar—(X) n II wherein each X is independently Cl, Br or I, and Ar, n and m are as set forth above, with a base in water to form therefrom the corresponding m-basic salt of the halogenated aromatic acid in water; (b) contacting the m-basic salt of the halogenated aromatic acid with a base in water, and with a copper source in the presence of a ligand that coordinates to copper, to form the m-basic salt of a hydroxy aromatic acid from the m-basic salt of the halogenated aromatic 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 m-basic salt of the hydroxy aromatic acid from the reaction mixture in which it is formed; and (d) contacting the m-basic salt of the hydroxy aromatic acid with acid to form therefrom an n-hydroxy aromatic acid.