Production process of α-hydroxy acids
AssigneeAsahi Kasei Chemicals Corporation
InventorsMakoto Okamoto, Hideki Date
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Abstract
An object of the present invention is to provide a production process of an α-hydroxy acid having a sufficient quality as a polymer raw material, which process does not produce a large amount of waste as a byproduct and is economical. The present invention provides a production process of an α-hydroxy acid having a step of adding a basic metal to an α-hydroxy acid ammonium salt to yield an α-hydroxy acid metal salt and a step of desalting the α-hydroxy acid metal salt to yield the α-hydroxy acid.
Claims23
A process for producing an α-hydroxy acid, which comprises:
- (1) a step of bringing a basic metal into contact with an aqueous solution of an α-hydroxy acid ammonium salt to produce an α-hydroxy acid metal salt while (i) controlling a concentration of an α-hydroxy acid amide residue in the solution to 500 [weight ppm/α-hydroxy acid] or less, and (ii) simultaneously removing ammonia generated in this step from the aqueous solution into a gas phase portion at a temperature exceeding 60° C., and
- (2) a step of desalting the α-hydroxy acid metal salt into the corresponding α-hydroxy acid.
A process for producing an α-hydroxy acid, which comprises:
- (1) a step of bringing a basic metal into contact with an aqueous solution of an α-hydroxy acid ammonium salt to produce an α-hydroxy acid metal salt while (i) controlling a concentration of an α-hydroxy acid amide residue in the solution to 500 [weight ppm/α-hydroxy acid] or less, and (ii) simultaneously introducing an inert gas into the solution, and
- (2) a step of desalting the α-hydroxy acid metal salt into the corresponding α-hydroxy acid.
Dependencies are inferred from the claim text.