GB1210495A - Selective crystallization - Google Patents

Abstract

1,210,495. Separating optical isomers; C- phenyl glycine. STRUTHERS SCIENTIFIC & INTERNATIONAL CORP. 23 Nov., 1967 [15 Nov., 1966; 23 June, 1967], Nos. 51077/66 and 29042/67. Heading C2C. [Also in Division B1] A process for the separation of optical isomers comprises the steps of (a) forming a solution of optical isomers; (b) cooling the solution to a degree sufficient to cause crystal growth without appreciable nucleation; (c) seeding the cooled solution with nuclei of one optical isomer; (d) allowing crystals to grow on the seed nuclei of the one optical isomer thereby forming a slurry; (e) removing small nuclei from the slurry; (f) recycling part of the slurry (freed from small nuclei) leaving step (e) back to step (d); (g) treating another part of the slurry (freed from small nuclei) from step (e) to remove crystals of one of the isomers therefrom; and (h) thereafter treating the solution from step (g) to recover at least one of the isomers therefrom. Small nuclei are separated in a filter, Fig. 3, in which a slurry is conducted through line 28 into body 29. Motor 32 drives the screw conveyer 33 to move large crystals across screen 30 to line 34. Mother liquor and fine craystals pass through screen 30 to leave through line 35. The separation of the isomers of C-phenyl glycine is described.