Method for efficiently producing glycine and identification of glycine produced by hydantoin method

Abstract

The invention belongs to the field of chemical engineering, and particularly relates to a method for efficiently producing glycine and identification of glycine produced by a hydantoin method. The production method of glycine comprises the following steps: reacting raw materials for producing glycine by a hydantoin method in a reactor at 150-175 DEG C under 5-8 MPa, carrying out stream stripping after the reaction, and obtaining glycine according to a conventional treatment mode. According to the invention, the impurity glycine dipeptide in a glycine product only exists in the product preparedby the hydantoin method, so that whether the glycine product is produced by the hydantoin method can be judged according to whether the product contains the glycine dipeptide. According to the invention, the glycine production method has the advantages that the effective conversion rate of glycolonitrile is high, and the generation of the byproduct glycine dipeptide of glycolonitrile is reduced;and glycine dipeptide only exists in a glycine product produced by a hydantoin method, and an identification method is provided.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a method for efficiently producing glycine and the identification of glycine produced by the hydantoin method. Background technique [0002] There are many preparation techniques for glycine, and the production of glycine by the hydroxyacetonitrile method is a method that has been reported more in recent years. Compared with the chloroacetic acid method, this method is more environmentally friendly and has attracted attention both at home and abroad. The hydroxyacetonitrile method is divided into two situations again: the first situation: as the patent CN1962611B discloses a kind of processing method using hydroxyacetonitrile as raw material to prepare glycine, that is to say, the mixed reaction of hydroxyacetonitrile and ammonia water to obtain the ammonia solution of aminoacetonitrile, will obtain The ammoniated solution is directly added dropwise to about 40% sodiu...

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Problems solved by technology

The hydroxyacetonitrile method is divided into two situations again: the first situation: as the patent CN1962611B discloses a kind of processing method using hydroxyacetonitrile as raw material to prepare glycine, that is to say, the mixed reaction of hydroxyacetonitrile and ammonia water to obtain the ammonia solution of aminoacetonitrile, will obtain The ammoniated solution is directly added dropwise to about 40% sodium hydroxide aqueous solution, and the hydrolysis reaction is carried out at 80°C, and then deamination treatment is carried out under negative pressure conditions to obtain a mixture of sodium glycinate and disodium iminodiacetate Aqueous solution; the obtained mixed aqueous solution of sodium glycinate and disodium iminodiacetic acid is acidified with concentrated sulfuric acid to about pH=5.5, then decolorized, concentrated at high temperature to take sodium sulfate, and the feed liquid after taking sodium sulfate is cooled to 30 ° C ~ 40 ° C crystallization to obtain the glycine crude product, and the mother liquor is recycled; but this process method has the following disadvantages: (1) the product is not easy to refine, and a large amount of low-value sodium sulfate is produced as a by-product, and the generation cost is relatively high; (2) containing glycine, imino disulfide Separation and purification of the mixture of acetic acid monosodium salt and sodium sulfate, the separation of the mixture of the three is difficult, resulting in high energy consumption for separation and purification, and difficulty in recycling; (3) A large amount of waste water and waste residues that are difficult to treat are produced

[0005] However, there are the following problems in the production of glycine in this process: due to the instability of hydroxyacetonitrile, hydroxyacetonitrile participates in the reaction under high temperature and pressure, which easily leads to the decomposition of raw materials, and the thermal decomposition and polymerization of hydroxyacetonitrile and the production of by-products make the yield of glycine reduce

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