Potassium Carbonate → 4,4'-Oxydiphthalic acid

Participants

Reaction Steps

4-Chlorophthalic anhydride (10 g, 55 mmol), potassium benzoate (1.0 g, 6.2 mmol), and N-methylpyrrolidinone (25 g) were heated to about 175.C. Potassium carbonate (3.87 g, 28 mmol) was added and the suspension was heated to about 175.C. After 2 hours, GC analysis indicated a greater than 97% conversion to 4,4'-oxydiphthalic anhydride. The solvent was removed under reduced pressure and the residue treated with an aqueous 25% sodium hydroxide solution. The solution was acidified with concentrated HCl. The solid was collected and dried to give 4,4'-oxydiphthalic acid (4.85 g) mixed with some sodium chloride. The tetra acid was cyclized and recrystallized from hot acetic anhydride (2.4 mL) and filtered to remove salts to give 4,4'-oxydiphthalic anhydride, 4.2 g.

Provenance & Evidence