Clean production method for co-producing glycine and iminodiacetic acid

Abstract

The invention relates to a clean production method for co-producing glycine and iminodiacetic acid. The method comprises the steps: performing ammoniation reaction on hydroxyacetonitrile and ammonia under the condition of high temperature to obtain ammoniation liquid, mixing the ammoniation liquid and alkali, performing pyrohydrolysis, performing deamination and decolorizing treatment, performing bipolar membrane electrodialysis to obtain a glycine-sodium aminodiacetate aqueous solution, performing desalting treatment on the obtained glycine-sodium aminodiacetate aqueous solution to obtain a glycine aqueous solution and a sodium aminodiacetate aqueous solution separately, concentrating, crystallizing and drying the glycine aqueous solution to obtain the glycine, and acidifying, crystallizing and drying the sodium aminodiacetate aqueous solution to obtain the iminodiacetic acid. By the method, coproduction of the glycine and the iminodiacetic acid can be realized, the utilization ratio of the raw materials is high, the effective conversion rate of the hydroxyacetonitrile can reach above 93 percent, other organic byproducts are avoided, the product yield is high, the production cost is low, the byproducts are few, the impurities are few, sodium hydroxide can be recycled, the yield of the glycine and the iminodiacetic acid is greatly increased, and the purity of the glycine and the iminodiacetic acid is greatly improved.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a clean production method for the joint production of glycine and iminodiacetic acid. Background technique [0002] Glycine is an important fine chemical product, which is widely used in medicine, food, chemical industry, pesticide and other fields. The preparation technology of glycine has multiple, and Chinese patent CN1962611B discloses a kind of technology that hydroxyacetonitrile method prepares glycine, comprises the following steps: 1) hydroxyacetonitrile, ammoniacal liquor are mixed, and the mol ratio of reaction material liquid is hydroxyacetonitrile:ammonia=1: 2~10, control the reaction temperature between 20~60°C, and the reaction time is 0.5~8 hours to obtain the ammonia solution of aminoacetonitrile; 2) directly add inorganic alkali to the ammoniated solution obtained in step 1), the reaction mass The molar ratio is aminoacetonitrile: inorganic base=1: 0...

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Problems solved by technology

The above-mentioned preparation process has mild reaction conditions, easy control, and simple post-treatment, but it has the following problems: the raw materials are easily decomposed, resulting in the pyrolysis polymerization of aminoacetonitrile and the formation of by-products, and the generation of more colored impurities makes decolorization difficult, and the amount of decolorizer is large. , high energy consumption, low product yield, high energy consumption, high production cost

But there are also problems, mainly including: 1. a large amount of low-value inorganic salt sodium sulfate by-product; 2. produce a large amount of salty, organic waste water; The separation and purification of aminodiacetic acid and sodium sulfate are not thorough, resulting in a low yield of glycine, a large amount of residues in the mother liquor, causing the mother liquor to be unable to circulate; 5. The cost of recycling iminodiacetic acid is too high (the quality of glycine and iminodiacetic acid Ratio is about 10: 1), and qualified iminodiacetic acid cannot be obtained; 6. The utilization rate of hydroxya

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