CN-122010752-A - Glycine preparation method

CN122010752ACN 122010752 ACN122010752 ACN 122010752ACN-122010752-A

Abstract

The invention belongs to the technical field of glycine preparation, and particularly discloses a preparation method of glycine. And controlling the reaction temperature, efficiently synthesizing ammonium chloroacetate from chloroacetic acid and liquid ammonia in a reactor, carrying out catalytic ammonolysis with ammonia in the reactor filled with a solid catalyst, realizing the continuity and reinforcement of the process, and obtaining glycine through alcohol precipitation, crystallization, separation and purification. The solid catalyst provided by the invention has the advantages of simple preparation, regeneration, long service life, no metal pollution, easily available raw materials, controllable cost, long-acting cyclic utilization, high efficiency, simple recovery and the like, and the method for preparing glycine by using the solid catalyst solves the problems of large consumption, high recovery cost, low production and purification efficiency and pollution caused by the traditional catalyst, and is a key technology for green and low-cost industrial production of glycine.

Inventors

SHANG HUIJIAN
WANG JINGYU
ZHANG LEI
LIU HONGMEI

Assignees

河北科技大学

Dates

Publication Date: 20260512
Application Date: 20260122

Claims (7)

1. A process for the preparation of glycine comprising the steps of: In a low alkanol solution, reacting ammonium chloroacetate with ammonia under the catalysis of a solid catalyst to obtain glycine, wherein the solid catalyst is at least one of strong acid cation exchange resin or strong alkali anion exchange resin; The low alkanol solution comprises C 2 ~C 3 low alkanol and water in a volume ratio of 1:9-9:1.
2. The method for preparing glycine according to claim 1, comprising the steps of: s1, reacting chloroacetic acid with liquid ammonia to obtain ammonium chloroacetate; s2, dissolving ammonium chloroacetate in a low-alkanol solution, and introducing the low-alkanol solution and ammonia gas into a reactor filled with a solid catalyst for reaction to obtain a glycine mixed solution; And S3, concentrating and crystallizing the glycine mixed solution to remove ammonium chloride, and then performing alcohol precipitation and crystallization to obtain glycine.
3. The process for producing glycine according to claim 1 or 2, wherein the strongly acidic cation exchange resin is a polystyrene sulfonic acid type ion exchange resin; the strong basic anion exchange resin is a strong basic acrylic anion exchange resin.
4. The process for producing glycine according to claim 2, wherein in S2, the reactor is at least one of a tubular fixed bed reactor, a multitubular fixed bed reactor, an adiabatic fixed bed reactor, a slurry bed reactor or a trickle bed reactor.
5. The method for preparing glycine according to claim 2, wherein in S1, the reaction temperature is-10 to 30 ℃ and the reaction time is 10 to 20min.
6. The process for preparing glycine according to claim 2, wherein in S2, the reaction temperature is 60 to 100 ℃ and the reaction time is 1 to 6 hours.
7. The process for producing glycine according to claim 2, wherein in S2, the lower alkanol is at least one of absolute ethanol and propanol.

Description

Glycine preparation method Technical Field The invention belongs to the field of glycine preparation, and particularly relates to a preparation method of glycine. Background Glycine is an important fine chemical intermediate widely applied to the fields of pesticides, medicines, foods and the like, and the main current production in China still depends on chloroacetic acid ammonolysis method taking urotropine as a catalyst. However, the traditional process has the prominent defects of high catalyst consumption, incapability of recycling, high production cost, multiple side reactions, high difficulty in product separation and purification, high waste liquid amount, difficult treatment and the like. In the prior art, although the catalyst circularity is improved by using ionic liquid as a catalyst for homogeneous synthesis, the ionic liquid has high cost and complex recovery process, the industrial application is limited, glycine and ammonium chloride are separated by electrodialysis, urotropine is recovered, the problems of mother liquor impurity enrichment, large equipment investment, high energy consumption and the like are still faced, the solvent volatilization loss is reduced by adopting high-boiling-point polar solvent to separate mixed crystals of glycine and ammonium chloride, the solvent circulation and recovery step is still involved, the cost of the high-boiling-point solvent is high, and the biological route for synthesizing glycine by using CO 2 as a raw material through enzyme catalysis has green environmental protection potential, but the enzyme activity and stability are insufficient at present, and the distance from industrialization is still kept. Therefore, how to design a solid heterogeneous catalyst which is simple in process and capable of being recycled to replace urotropine, solves the problems of high consumption, high recovery cost, low production and purification efficiency and pollution caused by the conventional catalyst, and becomes a key technical bottleneck for green and low-cost industrial production of glycine. Disclosure of Invention Aiming at the defects existing in the process of preparing glycine by using the traditional catalyst, the invention provides a solid catalyst which can be recycled for a long time, has high efficiency, is simple to recycle and has low cost, and a method for preparing glycine by using the solid catalyst. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: The invention provides a preparation method of glycine, which comprises the following steps: in the low alkanol solution, ammonium chloroacetate and ammonia react under the catalysis of a solid catalyst to obtain glycine. The solid catalyst is at least one of strong acid cation exchange resin or strong base anion exchange resin. The low alkanol solution comprises C 2~C3 low alkanol and water in a volume ratio of 1:9-9:1. The invention provides a novel glycine synthesis process based on strong acid or strong alkaline solid resin catalysis, which uses a recyclable solid heterogeneous catalyst to replace urotropine, solves the problems of high catalyst consumption, difficult recovery and pollution caused by the catalyst, and compared with the prior art, the preparation of the solid catalyst is relatively simple and mature, the regeneration is strong, the service life is long, no metal pollution is more suitable for high-end application, the cost of raw materials is easy to obtain and controllable, the invention uses strong acid cation exchange resin as the catalyst, can accurately guide a reaction path to generate glycine, uses strong alkaline anion exchange resin as the catalyst, has absolute safety, and can inhibit potential esterification side reaction to the maximum extent by using C 2~C3 low alkanol solution and mixed volume ratio. Preferably, the preparation method of glycine comprises the following steps: s1, reacting chloroacetic acid with liquid ammonia to obtain ammonium chloroacetate; s2, dissolving ammonium chloroacetate in a low-alkanol solution, and introducing the low-alkanol solution and ammonia gas into a reactor filled with a solid catalyst for reaction to obtain a glycine mixed solution; And S3, concentrating and crystallizing the glycine mixed solution to remove ammonium chloride, and then performing alcohol precipitation and crystallization to obtain glycine. According to the invention, chloroacetic acid and liquid ammonia are adopted to efficiently synthesize ammonium chloroacetate, and then catalytic ammonolysis is carried out with ammonia gas in a reactor filled with a solid catalyst, so that the continuity and reinforcement of the process are realized; the product system after the reaction has clear separation path, can directly obtain ammonium chloride through concentration crystallization and filtration, and obtains high-purity glycine through alcohol precipitation crystallization operation of filtrat