Device and method for preparing DL-methionine salt

Abstract

The invention discloses a device for preparing DL-methionine salt. The device comprises a three-stage series kettle type reactor and a gas stripping tower, wherein a material inlet of the gas stripping tower is communicated with a material outlet of the third-stage kettle type reactor. The invention also discloses a method for preparing the DL-methionine salt by using the device. The method comprises the following steps of charging an aqueous solution of hydantoin and an aqueous solution of inorganic alkali in the three-stage series kettle type reactor, performing continuous three-stage reaction, and controlling the pressure in the three-stage series reactor to be between 1.4 and 2.6MPa; performing gradient temperature rising of the first-stage reactor from 50 DEG C to 100 DEG C, performing gradient temperature rising of the second-stage reactor from 100 DEG C to 140 DEG C, and performing gradient temperature rising of the third-stage reactor from 140 DEG C to 180 DEG C; and feeding the liquid flowing out of the material outlet of the third-stage reactor to the atmospheric pressure vapor stripping tower, and separating and recycling carbon dioxide and ammonia, wherein the liquid flowing out of the bottom of the tower is an aqueous solution of DL-methionine salt, and the mixed gas discharged from the top of the tower is used for recycling and preparing an aqueous solution of carbon dioxide and ammonia and can be circularly used for preparing the hydantoin. By the device and the method, gradient temperature rising is easy to realize, high-efficiency mixing is realized, reaction is complete, reaction speed is high, a small quantity of by-products are generated, and yield is high; and moreover, the device and the method can be used for realizing the refinement of the DL-methionine salt conveniently and efficiently, and the DL-methionine salt has high quality.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to an improved preparation device and method of chemical products. Background technique [0002] Methionine, also known as methionine, is one of the basic units of protein. It is the only amino acid containing sulfur among the essential amino acids. In addition to participating in the transfer of methyl groups in animals, the metabolism of phosphorus and the synthesis of adrenaline, choline, and creatine In addition, it is also a raw material for the synthesis of protein and cystine. Methionine is widely used in the fields of medicine, food, feed and cosmetics, among which the largest amount is used as a feed additive. However, at present, almost all methionine in my country depends on imports, and the domestic production is very low, which is far from meeting the demand. [0003] DL-methionine salt is an intermediate for the preparation of DL-methionine by hydantoin (chemical name 5-...

AI Technical Summary

Problems solved by technology

In the existing technology, the hydrolysis of hydantoin to prepare DL-methionine salt is carried out under high temperature and high pressure conditions. The reaction conditions are not easy to control, and it is easy to cause side reactions such as degradation and polymerization of organic raw materials, thereby causing DL-methionine Amino acid salt yield drops or the process is unstable

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