Method and device for clean production of glycine

Abstract

The invention belongs to the field of a chemical industry and particularly relates to a method and device for clean production of glycine. The method for clean production of glycine comprises that hydroxyacetonitrile, ammonia, carbon dioxide and water as raw materials undergo a reaction in a special material synthesis reactor, the pressure of the synthesis reactor is reduced to the normal pressureso that a material liquid I is obtained, the material liquid I is heated and hydrolyzed, the pressure of the hydrolysate is reduced to the normal pressure, ammonia is removed so that a material liquid II is obtained, and the material liquid II is treated through a conventional treatment method so that glycine is obtained. The method is environmentally friendly and clean, does not produce by-products, has a high effective conversion rate of hydroxyacetonitrile, greatly improves the glycine yield through a special material, reduces the hydroxyacetonitrile by-products and produces glycine dipeptide to increase corrosion resistance of the material. The device is simple. The method is easy to operate and realizes a low cost.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a clean production method and device of glycine. Background technique [0002] There are many preparation techniques for glycine. The production of glycine by 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 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% sodium hydroxide aqueous solution, and the hydrolysis reaction is carried out at...

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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 mixed solution of acetic acid monosodium salt and sodium sulfate. The separation of the mixed solution of the three is difficult, resulting in high energy consumption for separation and purification, and it is difficult to recycle; (3) a large amount of waste water and waste residues that are difficult to treat are produced

[0005] But, there are following problems in the production of glycine in this process method: (1) due to the instability of hydroxyacetonitrile, hydroxyacetonitrile participates in the reaction under high temperature and pressure, which easily causes the decomposition of raw materials, and the thermal decomposition polymerization of hydroxyacetonitrile and its by-products produce, so that The yield of its glycine reduces; (2) owing to use excessive ammonia and carbon dioxide, under high temperature condition, these two kinds of gases are stronger to the corrosivity of fittings; In order to reduce the accumulation of by-products such as hydantinic acid, diketopiperazine, glycine dipeptide, etc., see the following chemical formula, and these impurities will be converted into glycine products under high temperature conditions; (4) the process needs to be It is carried out under high pressure conditions, so the requirements for equipment are extremely high

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