Patent ID: 8927766
Filing Date: 2015-01-06
Classification: C07C

Abstract:
1. A process for the preparation of glycolic acid, comprising (A) feeding carbon monoxide, methylene dipropionate, a homogeneous acid catalyst, propionic acid, and water to a hydrocarboxylation reaction zone to produce an effluent comprising said homogeneous acid catalyst and esters of glycolic and propionic acids; (B) recovering said homogeneous acid catalyst from said effluent by extracting said effluent with a first hydrophilic solvent and a first hydrophobic solvent selected from at least one of the group consisting of esters having from 4 to 20 carbon atoms, ethers having from 4 to 20 carbon atoms, ketones having from 4 to 20 carbon atoms, and hydrocarbons having from 6 to 20 carbon atoms 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 propionic 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).