Prepn. of methionine

Abstract

The present invention prepares easy to treat methionine with good crystal form and great bulk specific weight through the hydrolysis of 5-(beta-methylmercaptoethyl) hydantoin and the neutralization of hydrolysate with CO2 to separate methionine crystal. It features the continuous crystal separation in a crystal separating tank with casing. First, 15-40% of the hydrolysate and coagulant are filled in the tank and stirred while leading CO2 in so as to separate partial crystal, and then the rest hydrolysate, coagulant and CO2 is filled for continuous crystal separation.

Description

technical field

[0001] The invention relates to a method for preparing methionine, in particular to a method for preparing methionine with good crystal form and high volume ratio. Methionine is mainly used as a feed additive for animals. Background technique

[0002] The known preparation method of methionine is to hydrolyze 5-(β-methylmercaptoethyl)hydantoin in the presence of potassium carbonate, and then pass carbon dioxide into the hydrolyzate for neutralization to make methionine crystallization, separation, A cycle process of hydantoin hydrolysis by concentrating the filtrate (JP-A-54-9174).

[0003] However, the crystals of methionine obtained by the above method are in the form of scales and have a small specific gravity of only 0.3 to 0.4. Moreover, there are many acnes, and methionine is not easy to deal with. As an improved method, the scale-like methionine can be recrystallized to obtain plate-like methionine crystals with a large specific volume, but this met...