W. R. Grace Co.

William Philip Moore

Robert Wright Bragdon

Jon Carl Thunberg

Glycine can be recovered from an aqueous solution of glycine and sodium chloride having a mole ratio of glycine to sodium chloride of about 0.7-5:1 by: (a) adjusting the pH of the starting solution to 4.5-8.5 and evaporating water therefrom and cooling to precipitate glycine and to form a first mother liquor; (b) separating the precipitated glycine from the first mother liquor; and (c) recovering the separated glycine. Sodium chloride can be precipitated from the first mother liquor by evaporating water therefrom to form precipitated sodium chloride and a second mother liquor rich in glycine which can be separated from the precipitated sodium chloride and admixed with a second lot of the aqueous starting solution and processed therewith. Alternatively, the sodium chloride can be precipitated and separated before precipitating the glycine by: (a) evaporating sufficient water to cause sodium chloride to precipitate from the hot solution (mother liquor); (b) separating the precipitated sodium chloride from the hot mother liquor; (c) cooling the separated mother liquor to cause glycine to precipitate; and (d) separating the precipitated glycine from the cooled mother liquor. The cooled separated mother liquor can be admixed with a second lot of the aqueous starting solution and processed therewith.

Process for recovering glycine from sodium chloride solutions

Glycine can be recovered from an aqueous starting solution of glycine and sodium sulfate having a mole ratio of glycine to sodium sulfate of about 1-5:1 and a pH of about 4.5-8.5 by: (a) cooling the starting solution to precipitate a first lot of glycine and form a first mother liquor; (b) separating the precipitated glycine from the first mother liquor; (c) recovering the separated glycine; (d) precipitating a first lot of sodium sulfate from the first mother liquor by evaporating water therefrom to form a first lot of precipitated sodium sulfate and a second mother liquor; (e) separating the precipitated sodium sulfate from the second mother liquor; (f) admixing the separated second mother liquor with water and a second lot of the aqueous starting solution to form a first resulting solution; (g) cooling the first resulting solution to form a second lot of precipitated glycine and a third mother liquor; (h) separating the second lot of precipitated glycine from the third mother liquor; (i) evaporating water from the third mother liquor to precipitate a second lot of precipitated sodium sulfate and form a fourth mother liquor; (j) separating the second lot of precipitated sodium sulfate from the fourth mother liquor; (k) admixing the separated fourth mother liquor with water and a third lot of the aqueous starting solution to form a second resulting solution; (1) cooling the second resulting solution to form a third crop of precipitated glycine and a fifth mother liquor; and (m) separating the third crop of precipitated glycine from the fifth mother liquor. The separated fifth mother liquor can be concentrated to precipitate a third lot of sodium sulfate and to form a sixth mother liquor. Steps (j) through (m) can then be repeated. This procedure can be repeated indefinitely.

Process for recovering glycine from sodium sulfate solutions

.beta.-ALANINE IS RECOVERED FROM A STARTING SOLUTION OF SODIUM CHLORIDE AND .beta.-ALANINE BY: (A) EVAPORATING WATER FROM THE SOLUTION TO PRECIPITATE SODIUM CHLORIDE AND FORM A FIRST MOTHER LIQUOR; (B) SEPARATING THE FIRST MOTHER LIQUOR AND THE PRECIPITATED SODIUM CHLORIDE WHILE THE FIRST MOTHER LIQUOR IS HOT; (C) COOLING THE SEPARATED FIRST MOTHER LIQUOR TO PRECIPITATE .beta.-ALANINE AND FORM A SECOND MOTHER LIQUOR; (D) SEPARATING THE PRECIPITATED .beta.-ALANINE AND THE SECOND MOTHER LIQUOR; AND (E) RECOVERING THE SEPARATED .beta.-ALANINE. If desired, the separated second mother liquor can be admixed with a second lot of the starting solution and processed therewith.

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Hudson, NH, United States of America

William Philip Moore