METHOD OF OBTAINING METHIONINE Russian patent published in 2019 - IPC C07C319/20 C07C319/26 C07C319/28 C07C323/58 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for crystallising D, L-methionine from aqueous solutions and / or suspensions, which contain D, L-methionine and ammonium salt of D, L-methionine and have Met content of 70–180 g/kg solution and / or suspension, preferably 90–150 g/kg solution and / or suspension, and content of NH₄⁺ 1–5 g/kg solution and / or suspension. Method is carried out in the presence of a crystallising additive, which contains a non-ionic or anionic surfactant or a mixture of various non-ionic or anionic surfactants. Temperature of the solution and / or suspension is reduced immediately or gradually from T₁= 85–110 °C to T₂= 30–50 °C such that D, L-methionine precipitates as a solid. Method is characterised by that the anionic surfactant used for the formation of a crystallising additive is one of the compounds shown in formulae 1–3, or a mixture thereof. In formulae 1–3, n is an integer from 1 to 10, M is sodium or potassium, and R¹, R² and R³ are linear, branched or cyclic, saturated or unsaturated C₈-C₂₀-alkyl group or aryl group. Non-ionic crystallising additive is an ester of sorbitan and fatty acid or a mixture of various esters of sorbitan and fatty acid. Invention also relates to a method for producing D, L-methionine using this method of crystallising D, L-methionine. .

EFFECT: disclosed method allows to obtain D, L-methionine with high bulk densities.

22 cl, 1 dwg, 3 tbl, 4 ex