GB753705A - Improvements in or relating to process for preparing crystals of monocalcium diglutamate - Google Patents

Abstract

A process for preparing crystals of monocalcium diglutamate comprises preparing a solution containing monocalcium diglutamate, heating the solution to a temperature between about 60 DEG C. and about the boiling point, at which temperature the solution is at least saturated, agitating the hot solution while seeding with solid phase monocalcium diglutamate, crystallizing monocalcium diglutamate from the seeded solution and separating the crystals. The first solution may be prepared by mixing glutamic acid, water and a basic inorganic oxygen-containing compound of calcium or by reacting glutamic acid in water with calcium hydroxyglutamate or monocalcium monoglutamate trihydrate. The seeding material may be obtained by spray drying a solution of the salt, preferably after the removal of silicon and magnesium hydroxide and drying the spray dried material until anhydrous. The solution to be seeded may contain, for example 50 to 70 per cent by weight of the salt. The mono-calcium mono-glutamate trihydrate can be obtained by slurrying glutamic acid in water with calcium oxide or hydroxide until the pH is 10.6 to 10.8, usually at 50 DEG to 60 DEG C., separating insoluble matter and cooling to 20 DEG to 30 DEG C. Calcium hydroxyglutamate is prepared by reacting equimolecular amounts of glutamic acid and calcium oxide or hydroxide in aqueous medium, the solution after filtering being concentrated at 80 DEG to 90 DEG C. to give a solution containing about 10 to 15 per cent by weight of the salt. An example illustrates the process.