Sumitomo Chemical Company, Limited

Katsuharu Imi

Tetsuya Shiozaki

Shigeo Wake

Methionine is produced in an improved yield while reducing the load of waste water disposal by a process including the steps of: (A) adding at least one compound selected from potassium carbonate, potassium bicarbonate and potassium hydroxide to a solution containing 5-(.beta.-methylmercaptoethyl)hydantoin, (B) saturating the resulting solution with carbon dioxide gas and separating deposited methionine while leaving a first filtrate behind, (C) transferring part or whole of the first filtrate to step (D), (D) heating the transferred filtrate, adding a water-miscible solvent to it and saturating it with carbon dioxide gas to deposit methionine and potassium bicarbonate, and separating these deposits while leaving a second filtrate behind, and (E) returning the second filtrate to step (A) if desired.

Process for producing methionine

2-Butene-1,4-diol and/or 3-butene-1,2-diol are (is) reacted with hydrogen cyanide in the presence of a molten catalyst comprising a cuprous halide and a non-aromatic organic amine hydrohalide.

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Shiga-ken, Japan

Katsuharu Imi