Hydrogen fluoride removal from glycolic acid

• US 4,188,494 A
• Filed: 08/07/1978
• Issued: 02/12/1980
• Est. Priority Date: 04/25/1977
• Status: Expired due to Term

• Current Assignee: Chevron Research Company (Chevron Corp.)
• Original Assignee: Chevron Research Company (Chevron Corp.)
• Inventors: Suzuki, Shigeto
• Primary Examiner(s): Helfin, Bernard
• Assistant Examiner(s): Hendriksen, L.
• Application Number:
  US05/931,333
• Time in Patent Office: 554 Days
• Field of Search: 560/179, 562/580
• US Class Current: 562/580
• CPC Class Codes: C07C 51/42 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 51/44 by distillation
• CPC Class Codes: C07C 59/06 Glycolic acid

Abstract

The concentration of hydrogen fluoride in crude glycolic acid made by the hydrogen fluoride-catalyzed reaction of formaldehyde and carbon monoxide can be reduced to less than about 1% by weight by removing the HF from the crude gylcolic acid by distillation or stripping with inert gas at a temperature above about 130° C., thereby producing a polyglycolide subsequently convertible to glycolic acid by hydrolysis.

Claims

1. In a process for the removal of hydrogen fluoride by inert gas stripping or distillation from a crude glycolic acid obtained by the hydrogen fluoride catalyzed reaction of formaldehyde and carbon monoxide, the improvement which comprises effecting said removal at a temperature in excesss of about 130°

C. at atmospheric pressure to produce polyglycolide, thereafter hydrolyzing said polyglycolide and recovering pure glycolic acid.

2. A process according to claim 1 wherein hydrogen fluoride removal is carried out by gas stripping.

3. A process according to claim 1 wherein the hydrogen fluoride removal is carried out at a temperature of about 100°

C. for a period of time sufficient to obtain a product having about 4% by weight hydrogen fluoride and subsequent hydrogen fluoride removal is carried out at a temperature of about 130°

C. to 160°

C.

4. A proces according to claim 1 wherein the purification is carried out by inert gas stripping using a mixture of carbon monoxide and hydrogen as the inert gas.