Patent ID: 7378547

Claim:
A process for preparing a hydroxy aromatic acid that is described generally by the structure of Formula 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, 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 a Schiff base; (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.