METHOD FOR PREPARING 2-HYDROXY-4-METHYLTHIO- BUTANOIC ACID Russian patent published in 2003 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to synthesis of organic food supplement used for fodders in animal husbandry. For preparing 2- hydrxoy-4-methylthiobutanoic acid method involves conversion of 2-hydroxy-4-methylbutyronitrile to 2-hydroxy-4-methylthiobutaneamide in the presence of sulfuric acid followed by its hydrolysis by addition to reaction mixture of an aqueous solution containing ammonium bisulfate and ammonium sulfate. This results to preparing oily layer containing 2-hydroxy-4-methylthiobutanoic acid and an aqueous layer containing ammonium bisulfate and ammonium sulfate. Part of ammonium salts is isolated from an aqueous layer by crystallization and prepared an aqueous solution containing ammonium bisulfate and ammonium sulfate is recirculated to the hydrolysis stage. Method provides preparing the end product of high quality being without using organic solvents and with significantly reduced amount of sewage. EFFECT: improved preparing method. 14 cl, 13 tbl, 1 dwg, 5 ex