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US 9,040,748 B2Granted
Hydrocarboxylation of aqueous formaldehyde using a dehydrating recycle stream to decrease water concentration
AssigneeEastman Chemical Company
InventorsMesfin Ejerssa Janka, Scott Donald Barnicki, Robert Thomas Hembre, Kelley Margaret Moran, Stephen Neal Falling
Life of this patent
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Abstract
Disclosed is a process for the production and purification of glycolic acid or glycolic acid derivatives by the carbonylation of aqueous formaldehyde. The water in the hydrocarboxylation zone is reduced via reaction with the ester bonds in a recycle stream comprising glycolic acid oligomers and/or methyl glycolate oligomers.
Claims17
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.
2 more elements
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, methyl glycolate, methyl glycolate oligomers, and water;
- (B) dehydrating said effluent in the presence of methanol to produce a first dehydration stream having a degree of polymerization (Dp) higher than said effluent and an overhead stream comprising water and methanol;
- 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.
2 more elements
Dependencies are inferred from the claim text.