METHOD OF PRODUCING METHIONINE Russian patent published in 2010 - IPC C07C319/20 C07C319/28 C07C323/58 

FIELD: chemistry.

SUBSTANCE: method involves the following steps: a) addition of at least one component selected from potassium carbonate, potassium bicarbonate or potassium hydroxide, to a solution containing 5-(β-methylmercaptoethyl)hydantoin for hydrolysis of 5-(β-methylmercaptoethyl)hydantoin to obtain a solution containing methionine; b) saturation of the solution containing methionine, carbon dioxide with precipitation methionine and separation of precipitated methionine together with separation of a first filtrate; c) division of the first filtrate into a first portion and a second portion, returning the first portion to step (a) and taking the second portion to step (d), where the first portion of the first filtrate may not be present; d) heating the second portion of the first filtrate to temperature above 200°C and pressure of water vapour formed during dwell time sufficient to obtain a filtrate heated to the required temperature, where the filtrate subjected to the said thermal treatment is directly saturated with carbon dioxide with precipitation of methionine and potassium bicarbonate, and the precipitated methionine and potassium bicarbonate are separated while also separating a second filtrate; and e) removal of the second filtrate or returning it to step a).

EFFECT: method increases ultimate yield of the desired methionine product enables attainment of high values of space-time output.

9 cl, 1 tbl, 1 dwg, 1 ex