Clean process for continuously synthesizing glycine

A process method and technology of glycine, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as low hydrolysis single-pass yield, long hydrolysis time, and difficulty in applying mechanically, so as to shorten the hydrolysis reaction time, Facilitate absorption and improve single-pass conversion rate

Inactive Publication Date: 2020-07-31
龙智
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the excess ammonia and carbon dioxide in the system and the ammonia and carbon dioxide released by hydrolysis are all recovered after the completion of the two-stage reaction, which increases the difficulty of recycling ammonia and carbon dioxide, and is not conducive to the progress of the hydrolysis reaction, and the single-pass yield of hydrolysis is low ; In the proportioning of raw materials, the amount of ammonia is greater than the amount of carbon dioxide, so that the side reaction of ammoniating hydroxyacetonitrile to generate iminodiacetonitrile is more obvious, which affects the yield and purity of product glycine
Chinese patents CN201710969775 .3 and CN201910370199 .X both propose the use of tank-type series reactors to realize the hydrolysis of hydantoin, which also has the problems of long hydrolysis time, low yield per pass of hydrolysis, difficult recovery of ammonia and carbon dioxide, and side reactions of iminodiacetonitrile formation Weaknesses not well contained
Although the microchannel reactor can realize the continuous synthesis of glycine well, because the synthesis and hydrolysis of hydantoin are not fast reactions, the advantages of the microchannel reactor cannot be fully utilized, and its production capacity is small and its corrosi

Method used

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  • Clean process for continuously synthesizing glycine
  • Clean process for continuously synthesizing glycine
  • Clean process for continuously synthesizing glycine

Examples

Experimental program
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Effect test

Embodiment 1

[0047] Example 1: Ammonia, carbon dioxide and water are prepared in a molar ratio of 1:1:12 to prepare an aqueous solution of carbon dioxide and ammonia. The feed flow rate is 390kg / h, which is preheated to 80°C by a preheater, and 44wt% of the feed flow rate is 63.5kg / h The concentrated hydroxyacetonitrile solution is mixed rapidly in a static mixer, enters the column reactor from the bottom, and reacts at a pressure of 5.5 MPa and a temperature of 110°C for 45 minutes to obtain a hydantoin synthetic liquid, which then flows out from the top of the reactor and enters a decompression flasher; The operating pressure of the evaporator is 1.5MPa, and the gas phase separated by flash is removed from the carbon dioxide and ammonia recovery system, and the liquid phase enters 3-stage series column reactors for continuous hydrolysis, and the materials of each stage of the reactor enter from the bottom and flow out from the top; the hydrolysis reaction The operating pressure of the rea...

Embodiment 2

[0050] Example 2: Ammonia, carbon dioxide and water are prepared in a molar ratio of 1:1.15:15 to prepare an aqueous solution of carbon dioxide and ammonia. The feed flow rate is 4200kg / h, preheated to 80°C by a preheater, and the feed flow rate is 590kg / h with a concentration of 40wt%. The hydroxyacetonitrile solution is mixed rapidly in a static mixer, enters the tube bundle reactor from the bottom, reacts at a pressure of 4.5MPa and a temperature of 120°C for 35min, and then flows out from the top of the reactor into a decompression flasher; the operating pressure of the flasher is 1.0MPa, The gas phase of flash separation is used to remove carbon dioxide and ammonia recovery system, and the liquid phase enters the compound reactor combining 5-stage series column reactors and tube bundle reactors for continuous hydrolysis. The materials of each stage of reactor enter from the bottom, from The upper part flows out; the operating pressure of the hydrolysis reactor is 2.5MPa, a...

Embodiment 3

[0053] Example 3: Ammonia, carbon dioxide and water are prepared in a molar ratio of 1:1.2:15 to prepare an aqueous solution of carbon dioxide and ammonia. The feed flow rate is 4250kg / h, preheated to 90°C by a preheater, and the feed flow rate is 670kg / h with a concentration of 38wt%. The hydroxyacetonitrile solution is mixed rapidly in a static mixer, enters a column reactor from the bottom, reacts at a pressure of 4.0MPa and a temperature of 100°C for 60min, and then flows out from the top of the reactor into a decompression flasher; the operating pressure of the flasher is 2.2MPa, The flash separation gas phase removes carbon dioxide and ammonia recovery system, and the liquid phase enters a compound reactor combining 6-stage series column reactors and tube-bundle reactors for continuous hydrolysis. The materials of each stage of reactor enter from the bottom, from Outflow from the upper part; the operating pressure of the hydrolysis reactor is 3.8MPa, and the temperature i...

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Abstract

The invention discloses a clean process for continuously synthesizing glycine. The process comprises the following steps: preheating a carbon dioxide ammonia water solution prepared from an ammonia source, a carbon source and water, mixing the preheated solution with glycolonitrile, performing continuous synthesis, reduced pressure flash evaporation, continuous hydrolysis, gas stripping, concentrating, cooling and crystallizing, centrifuging for the first time, carrying out hot-melting recrystallization, centrifuging for the second time and drying to obtain a glycine product. Part of carbon dioxide generated by hydrolysis in the hydrolysis reaction process is continuously separated; and a carbon dioxide and ammonia recovery system sequentially absorbs the gas phase obtained by gas stripping, hydrolysis separation and reduced pressure flash separation to obtain a carbon dioxide ammonia water solution, and the carbon dioxide ammonia water solution is recycled to the reaction system. According to the process, the yield of glycine is increased by restraining iminodiacetonitrile side reaction; through timely release of each gas phase in the system and reasonable arrangement of the recovery sequence, the difficulty of recycling carbon dioxide and ammonia in the system is reduced, the loss of carbon dioxide and ammonia is reduced, the hydrolysis one-way conversion rate is improved, the hydrolysis time is greatly shortened, and the process is an environment-friendly and clean process for producing glycine.

Description

technical field [0001] The invention relates to a clean process method for continuously synthesizing glycine by using hydroxyacetonitrile as a raw material through a hydantoin process, belonging to the field of fine chemical intermediates. Background technique [0002] Glycine, also known as aminoacetic acid, English Glycine, chemical formula C2H5NO2, molecular weight 75.07, is the simplest amino acid structure, as an important fine chemical intermediate, widely used in pesticides, medicine, food, feed, daily chemical and organic synthesis and other fields. my country is the largest producer and consumer of glycine in the world, and the market size of glycine exceeds 350,000 tons. [0003] The conventional production process of glycine in my country is the ammonolysis of chloroacetic acid. However, with the strengthening of environmental awareness in recent years, the environmental problems brought about by the ammonolysis of chloroacetic acid have become increasingly promi...

Claims

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Application Information

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IPC IPC(8): C07C227/24C07C229/08C07C227/40C07D233/74
CPCC07C227/24C07C227/40C07D233/74C07C229/08
Inventor 龙智李宽义黎能明
Owner 龙智
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