PURIFICATION OF HYDROXYACETIC ACID

• US 3,859,349 A
• Filed: 02/15/1973
• Issued: 01/07/1975
• Est. Priority Date: 02/15/1973
• Status: Expired due to Term

• Current Assignee: Nicholas Francis Cody
• Original Assignee: Nicholas Francis Cody
• Inventors: Cody, Nicholas Francis
• Primary Examiner(s): Weinberger, Lorraine A.
• Assistant Examiner(s): Killos, Paul J.
• Application Number:
  US05/332,578
• Time in Patent Office: 691 Days
• Field of Search: 260/535R
• US Class Current: 562/580
• CPC Class Codes: C07C 51/42 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 51/47 by solid-liquid treatment; by chemisorption
• CPC Class Codes: C07C 59/06 Glycolic acid

Abstract

Crude hydroxyacetic acid made by the carbonylation reaction of formaldehyde and water in the presence of an organic acid and sulfuric acid is purified by the following steps. The crude acid is first treated with granulated activated carbon for decolorization, then treated in a weak anion resin column to remove the sulfuric acid, subjected to live steam stripping to remove low-boiling impurities, and finally treated with a cation exchange resin to remove metals present, e.g., iron or copper.

Claims

1. A METHOD OF PURIFYING CRUDE HYDROXYACETIC ACID, SYNTHESIZED BY THE CARBOYLATION OF FORMALDEHYDE AND WATER IN AN ORGANIC ACID WITH SULFURIC ACID AS A CATALYST, CHARACTERIZED IN THAT THE CRUDE ACID IS DECOLORIZED BY BEING CONTACTED WITH A BED OF GRANULATED ACTIVATED CARBON, THEN SULFURIC ACID IS REMOVED FROM THE CRUDE ACID BY CONTACTING IT WITH A WEAK ANION EXCHANGE RESIN TO ABSORB THE SULFURIC ACID, AND THE LOW-BOILING IMPURITIES ARE THEN REMOVED BY LIVE STEAM STRIPPING AT TEMPERATURES OF 110* TO 120*C.

2. The method of claim 1 wherein the granulated activated carbon is in a pulsed bed.

3. The method of claim 1 wherein the acid from the live steam stripping is treated with a cation exchange resin for the removal of metal impurities.

4. The method of claim 3 wherein the absorbtion of the sulfuric acid by the weak anion exchange resin is interrupted while at least 33% of the resin remains in the active form.

5. The method of claim 4 wherein about 50% of the resin remains in the active form.