The direct saponification of methionine nitrile obtained from methylmercaptopropionaldehyde, prussic acid and ammonia gives low yields, catalyst and educt losses and unwanted side-products. The aim of the invention is therefore to provide a method which can be carried out without isolating the intermediate products, in particular continuously, and with low losses. The ketone used is recovered in high yields after amide saponification since this liberates the ketone from side-products. In order to recover the ammonia, it is necessary for the ammonia to be substantially freed of ketone, the mixture of ammonia, ketone and water obtained being separated under pressure in a separation column. When the amide is saponified at .gtoreq.160.degree. C., amide concentrations of less than 25% by wt. are preferred. Methionine nitrile is produced by treatment with at least 4 equivalents of .gtoreq.50% by wt. ammonia at between 40.degree. and 80.degree. C./or between 5 and 60 min. Cyanide residues are destroyed by heating to over 150.degree. C. Methionine is of particular use as a feedstuff, in particular in aqueous solution.
从甲基巯基
丙醛、
氰酸和
氨制得的甲
硫氨酸腈的直接皂化反应收率低,催化剂和原料损失大,产生不必要的副产物。因此,本发明的目的是提供一种无需分离中间产物的方法,特别是连续地和低损失地进行。在酰胺皂化后,使用的酮可以高产率地回收,因为这会使酮从副产物中释放出来。为了回收
氨,必须使
氨基本上从酮中解放出来,获得的
氨、酮和
水混合物在分离柱中在压力下分离。当酰胺在≥160℃下皂化时,优选酰胺浓度低于25%重量。通过在40℃至80℃/或5至60分钟之间用至少4当量的≥50%重量
氨处理来制备甲
硫氨酸腈。通过加热至超过150℃来破坏
氰化物残留。甲
硫氨酸在饲料中特别有用,特别是在
水溶液中。