Patent ID: 8765999

Claim:
A process for the preparation of glycolic acid, comprising (A) feeding carbon monoxide, aqueous formaldehyde, a homogeneous acid catalyst, and a carboxylic acid having 3-6 carbon atoms to a hydrocarboxylation reaction zone to produce an effluent comprising said homogeneous acid catalyst and esters of glycolic and carboxylic acids; (B) recovering said homogeneous acid catalyst from said effluent by extracting said effluent with a first hydrophilic solvent to form a first aqueous extract phase comprising a major amount of said homogeneous acid catalyst contained in said effluent and a first organic raffinate phase comprising a major amount of said esters of glycolic and carboxylic acids contained in said effluent; (C) separating said first organic raffinate phase and said first aqueous extract phase; and (D) recycling said first aqueous extract phase to step (A).