To provide a method for producing methionine stably for a long period, preventing effectively corrosion of a reaction vessel relative to both of a liquid phase part and a vapor phase part of hydrolysis solution even in the case of hydrolysis at a higher temperature, when producing methionine by hydrolyzing M-hydantoin in the presence of a basic potassium compound.
In this method for producing methionine by hydrolyzing 5-(β-methylmercaptoethyl) hydantoin in the presence of a basic potassium compound in water, hydrolysis is performed with basic potassium concentration of ≤9.5 wt.%, at a hydrolysis temperature of ≥170°C, and in a reaction vessel whose inner surface is constituted of stainless steel having a 21.0-30.0 wt.% Cr element content, a 4.5-11.0 wt.% Ni element content, a 1.0-5.0 wt.% Mo element content, a 0.05-0.50 wt.% N element content, a ≤0.50 wt.% W element content and a ≤0.10 wt.% Cu element content.
NISHIDA JUNICHI
YANO MASAYA
山本 健二
村田 美由紀
田村 弥栄子
鎌田 光宜
高島 一
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