A method for the continuous preparation of methionine or methionine derivatives (methionine or methionine derivatives)

摘要

Direct saponification of methionine obtained from methyl mercaptopropionate aldehyde, fulvic acid and ammonia results in low yields, loss of catalyst and vitreous and undesired by-products. It is therefore an object of the present invention to provide a process by which intermediate products are not separated, in particular, can be carried out continuously with little loss. The ketone used is recovered in high yield after the amide saponification because it releases the ketone from the byproduct. It is essential to substantially remove the ketone from the ammonia to recover the ammonia and to separate the obtained mixture of ammonia, ketone and water under pressure in the separation column.;When the amide is saponified at 160C or higher, the amide concentration is preferably less than 25% by weight. Methionine nitrile is prepared by treating at 40 to 80C for 5 to 60 minutes with at least 4 equivalents of ammonia at 50 wt% or more. Cyanide residue is destroyed by heating to above 150C. Methionine is especially used as a feed in the form of an aqueous solution.