Process for the synthesis of hydroxy aromatic acids

A process for preparing a hydroxy aromatic acid that is described by the structure of Formula I

• (COOH)m—Ar—(OH)n I
• wherein Ar is a C6-C20 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 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 a diketone described by Formula IV
• wherein A is
• R1 and R2 are each independently selected from substituted and unsubstituted C1-C16 n-alkyl, iso-alkyl and tertiary alkyl groups;
• and substituted and unsubstituted C6-C30 aryl and heteroaryl groups;
• R3 is selected from H;
• substituted and unsubstituted C1-C16 n-alkyl, iso-alkyl and tertiary alkyl groups;
• substituted and unsubstituted C6-C30 aryl and heteroaryl groups;
• and a halogen;
• R4, R5, R6 and R7 are each independently H or a substituted or unsubstituted C1-C16 n-alkyl, iso-alkyl or tertiary alkyl group;
• and
• n=0 or 1;
• (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.