Patent ID: 9040748
Filing Date: 2015-05-26
Classification: C07C

Abstract:
1. A process for the preparation of glycolic acid, comprising (A) feeding carbon monoxide, aqueous formaldehyde, and a recycle dehydration stream to a hydrocarboxylation reaction zone to produce an effluent comprising glycolic acid, glycolic acid oligomers, and water; (B) dehydrating said effluent to produce a first dehydration stream having a higher degree of polymerization (Dp) than said effluent and a water stream; and (C) splitting said first dehydration stream into said recycle dehydration stream of step (A) and an intermediate stream, wherein said feeding of said recycle dehydration stream and said aqueous formaldehyde of step (A) occurs at a molar ratio of ester bond equivalents:water of from 0.2:1 to 4:1.