Production method of feed-grade and food-grade glycine and device for implementing production method

Abstract

The invention relates to a production method for feed-grade and food-grade glycine and a device for implementing the method. The method comprises the following steps: with an aqueous hydroxyacetonitrile solution and an aqueous ammonium carbonate solution as raw materials, sequentially conducting reacting at 100-135 DEG C and 150-160 DEG C in the presence of a zirconium raw material, and controlling the liquid level of the reactions to be 75% or more; in the presence of the zirconium raw material, concentrating obtained reaction feed liquid under heating, removing ammonia and carbon dioxide, and then performing decoloration; and then in the presence of the zirconium raw material, subjecting the obtained decoloration solution to vacuum concentration and crystallization so as to obtain feed-grade and food-grade glycine products, wherein the yield of glycine is 97% or above in terms of glycolonitrile. The production method has the advantages that almost no three wastes are generated, the method is clean and environment-friendly, no organic solvent is needed, repeated recrystallization is not needed, the yield of feed-grade and food-grade glycine is high, production cost is low, an automation degree is high, and the like.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a production method of feed-grade and food-grade glycine and a device for implementing it. Background technique [0002] Glycine is an important chemical product, mainly used in pesticide, food and pharmaceutical industries. In the pesticide industry, it is mainly used to produce the herbicide glyphosate; in the food industry, it is used alone or in combination with sodium glutamate as a flavoring agent, and it is also used in the synthesis of wine, brewing products, and can also be used as butter, margarine and Cheese additive to prolong its shelf life; in the pharmaceutical industry, it can be used as a buffer for amino acid preparations, aureomycin, and as a synthetic raw material for Parkinson's disease drug L-dopa. In addition, glycine can also be used as biochemical reagents and solvents in organic synthesis and biochemistry. [0003] The global production of ...

AI Technical Summary

Problems solved by technology

But there is following shortcoming in this method: by-products such as ammonium chloride are difficult to remove, product and ammonium chloride are separated difficultly, produce a large amount of difficult-to-handle saline, contain glycine waste water, product quality is poor, and chloride ion content is higher in the product, to follow-up The corrosiveness of the equipment is difficult to overcome, and the refining cost is high; the catalyst hexatropine cannot be recovered, the production cost is high, and the reaction time is long

However, at present, there are mainly the following technical problems in the synthesis of glycine by hydantoin method: 1) due to the poor thermal stability of raw material hydroxyacetonitrile, it is easy to decompose, polymerize and generate other by-products when participating in the reaction under high temperature and pressure, so that glycine can be collected 2) Due to the excessive amount of ammonia and carbon dioxide in the system, it is highly corrosive to pipe fittings under high temperature and high pressure reaction conditions; 3) The glycine crystallization mother liquor contains byproducts such as hydantoin acid and glycine dipeptide , diketopiperazine and other products, in order to reduce their accumulation, they are often applied to the previous reaction steps to convert these impurities into glycine products at high temperature. Equipment materials and applied technical requirements are relatively high

However, the above-mentioned Hein process that has been reported does not mention the problem of glycine mother liquor circulation and the problem of impurity conversion in glycine mother liquor, and the impact of liquid level control on the conversion rate of hydroxyacetonitrile and product yield.

Due to the accumulation of impurities, the purity of the product obtained by the above method is only about 95%, which can only meet the requirements of industrial grade. In order to obtain feed grade and food grade glycine, multiple recrystallization and decolorization treatments are required, resulting in high crystallization energy consumption and Consuming a large amount of activated carbon, how to control the production of impurities and their removal and transformation in the production process of Heinfag glycine has become a technical problem that needs to be solved in the current method

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