Method of recovering purified glycolic acid from its contaminated aqueous solutions
AssigneeSuddeutsche Kalkstickstoff-Werke Aktiengesellschaft
InventorsUlrich Metz, Horst Michaud
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Abstract
Pure glycolic acid is recovered practically completely from the product obtained by hydrolysis of glycolonitrile containing at least stoichiometrically equivalent amounts of ammonium and sulfate ions by extraction with a mixture of a trialkyl phosphate and a dialkylether, preferably of equal weights of tributyl phosphate and diisopropyl ether, and separation of the glycolic acid from the extraction medium by contact with water.
Claims7
A method of recovering purified glycolic acid from an aqueous solution thereof contaminated with ammonium and sulfate ions in respective amounts at least stoichiometrically equivalent to said glycolic acid which comprises:
- a. contacting said contaminated solution with an extraction medium consisting essentially of a mixture of a trialkyl phosphate with a dialkyl ether until said glycolic acid is dissolved in said extraction medium,
- 1. alkyl in said trialkyl phosphate having up to six carbon atoms,
- 2. alkyl in said dialkyl ether having two to five carbon atoms,
- 3. each of said trialkyl phosphate and said dialkyl ether constituting at least 10% by weight of said medium;
- and
- b. separating said glycolic acid from said extraction medium.
Dependencies are inferred from the claim text.