GB443705A - Acid calcium lactates and methods of preparing same - Google Patents

Abstract

Acid calcium lactates in anhydrous crystalline form, containing 3 and 4 molecules of lactic acid to one atom of calcium referred to as CaL3 and CaL4 respectively, are prepared by crystallization from solutions containing an excess of lactic acid beyond the quantity combined with the calcium; the CaL3 being crystallized from ethyl alcohol, and the CaL4 from water, methylalcohol, acetone, or acetic acid. The excess of lactic acid in the solution may be 5--15 per cent in the case of CaL3 and 50 per cent in the case of CaL4. To produce CaL3, a solution of calcium lactate or carbonate in lactic acid may be evaporated to dryness and the residue dissolved in ethyl alcohol containing free lactic acid and crystallized, or the excess lactic acid may be added to the initial solution, in which case it need not be added to the alcohol. To produce CaL4, a solution of calcium lactate or carbonate in water, methyl alcohol, acetone, or acetic acid containing a large excess of lactic acid is crystallized; for instance, lactic acid may be partially neutralized with calcium carbonate and the solution evaporated until it contains 30 per cent of water, when methyl alcohol is added and the mixture cooled for the crystallization, but if desired the evaporation may be stopped when the solution contains 50 per cent of water; or the water remaining may be 10--20 per cent, when methyl alcohol, acetone, or glacial acetic acid is added and the mixture cooled. The Specification as open to inspection under Sect. 91 includes crystallizing the lactates from solvents miscible with water and lactic acid or an aqueous medium containing such solvents. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to a document other than Specifications.