Production process of glycine

Abstract

The invention discloses a production process of glycine. The production process comprises the following steps of: S1, performing ammonification; S2, performing alkaline hydrolysis ammonia distillation; S3, performing decolorizing with activated carbon; S4, performing ion exchange acidification separation, specifically, performing ion exchange reaction on metal ions of discolored glycinate and H < + > on ion exchange resin to generate glycine, discharging the glycine out of a system along with an aqueous solution, performing ion exchange reaction on iminodiacetic acid disalt and the H < + > to generate iminodiacetic acid monosalt, adsorbing the iminodiacetic acid monosalt on the resin, discharging the iminodiacetic acid monosalt and an inorganic salt solution generated in a resin regeneration process out of the system; S5, concentrating and crystallizing glycine, and when the iminodiacetic acid monosalt in circulating mother liquor is accumulated to 10% or above of the total solute, pumping out the mother liquor, concentrating and crystallizing the inorganic salt, and when iminodiacetic acid monosalt in the solute of the circulating mother liquor is accumulated to 15% or above of the total solute, extracting the mother liquor; S6, mixing the extracted mother liquor, and carrying out continuous chromatographic separation; and S7, recycling the iminodiacetic acid. The production process of the glycine provided by the invention has good glycine synthesis and separation effects.

Description

technical field [0001] The invention belongs to the technical field of chemical engineering and relates to a production process of glycine. Background technique [0002] Glycine, also known as glycine or glycine, is the compound with the simplest structure among amino acids, and is an important intermediate in organic synthesis, widely used in medicine, food, pesticide, feed and other industries. [0003] Compared with the traditional ammonolysis process of chloroacetic acid, the glycine synthesis process using hydroxyacetonitrile as raw material has the advantages of good product quality and less waste water. The existing industrial process for synthesizing glycine with hydroxyacetonitrile is: 1) ammoniation: a certain concentration of hydroxyacetonitrile (40% to 50%) and ammoniacal liquor (20% to 35%) are ammoniated in a tubular reactor to produce aminoacetonitrile , 2) Alkaline hydrolysis and ammonia distillation: aminoacetonitrile reacts with alkali, and alkali hydrolys...

AI Technical Summary

Problems solved by technology

But, there are following problems in this scheme: 1) adopt single-tubular reactor, the radial temperature difference of reactor easily causes in industrial scale-up, can't accurately control reaction temperature; There is no clear control index for the residual ammonia in the reaction solution, and too much residual ammonia will not only increase the probability of side reactions in the subsequent separation process, but also lead to high ammonia content in the wastewater, which cannot be directly biochemical; 3) The by-product iminodiacetic acid is discharged as waste liquid, entraining a large amount of glycine, resulting in a decrease in product yield, a large amount of waste liquid, and high processing costs; 4) using multi-stage concentrated crystallization to separate and purify glycine and inorganic salts, not only glycine has experienced many Sub-high temperature, increased aggregation and heavy components, and increased energy consumption

The innovation of this technical solution is to use bipolar membrane to electrically separate salt and organic matter, but there are following defects: 1) high energy consumption, the energy consumption of adopting bipolar membrane electrodialysis separation is too high, 2) glycine and iminodiacetic acid The continuous chromatographic and electrodialytic separation settings for the monosodium salt of the monosodium salt are unreasonable, the energy consumption of electrodialysis is high, a large amount of water is required as the mobile phase in the continuous chromatographic separation process, and the amount of water added is generally more than twice that of the material to be separated. Therefore, although the energy consumption of the chromatographic separation process is not high, the concentration of the solution after separation requires additional vaporization of a large amount of water, resulting in a multiplied increase in energy consumption and poor technical and economic indicators.

This technical scheme uses chromatography to separate low-concentration, high-flow glycine and iminodiacetic acid monosodium salt, and its energy consumption will increase by nearly 1 / 2 compared with the traditional process, which is very unfavorable for industrial production

Not only that, but there are also obvious mistakes in this patent that do not match the technical facts. 1) Bipolar membrane electroseparation is to separate salt and organic matter, so the two streams of material produced after separation should be (a) sodium iminodiacetate+ Sodium hydroxide mixed concentrated solution, (b) glycine solution, instead of (a) iminodiacetic acid sodium + glycine mixed solution, (b) sodium hydroxide solution; 2) the alkaline hydrolysis product of aminoacetonitrile is sodium glycinate and Sodium iminodiacetate instead of glycine and sodium iminodiacetate as described in this patent

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