Method for preparing collagen sugar

Abstract

The present invention discloses a preparation method of glycine. In the preparation method, chloroacetic acid and ammonia are used as raw materials; urotropine is used as the catalyst of the reaction; low-carbon alcohol solvent is used as a reaction medium; organic amine is added into the reaction system to be used as an acid binding agent; after the reaction is completed, the glycine with high content can be prepared through filtration. The preparation method solves the problems of the solvent that can not be recycled, serious solvent consumption, high cost, low yield, serious three-waste pollution and so on in the prior art. And the preparation method is suitable for the industrial production of the glycine.

Description

technical field [0001] The invention belongs to the field of fine chemicals, and in particular relates to a method for preparing glycine from chloroacetic acid and ammonia as raw materials. Background technique [0002] Glycine is aminoacetic acid, as an important fine chemical intermediate and chemical raw material, it is widely used in pesticides, medicines, food and feed additives and other fields. At present, there are many ways to prepare glycine, but the synthesis processes that can be industrialized or have industrialization prospects are mainly chloroacetic acid ammonolysis method, Strecker method and biosynthesis method using formaldehyde and sodium cyanide as main raw materials. Among them, the ammonolysis method of chloroacetic acid has a mature process route and simple equipment, and is currently the main method for producing glycine. [0003] Literature "Process Control and Quality", August 1996, Issue 1, 41-45; "Journal of Sichuan Union University (Engineering...

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Problems solved by technology

The above-mentioned aqueous phase glycine production method has problems such as that the catalyst cannot be recovered, the consumption of the catalyst is large, the catalytic efficiency is low, and the unreacted raw materials cannot be recovered and used mechanically, and due to the strong alkalinity and water content of the system, the hydrolyzate glycolic acid is easily generated. Thereby causing waste and polluting the environment; in addition, there are also defects such as difficulty in separation of inorganic salts such as ammonium chloride produced in the reaction, large amount of post-treatment, and difficulty in judging the end point of the synthesis reaction.

[0004] "Journal of Nanchang University (Science Edition)" the 3rd period of volume 24 in September, 2000 and patent document CN1410417 report take chloroacetic acid, ammonia as raw material, urotropine is catalyst, and solvent is the glycine preparation method of alcohol phase, this method Glycine is prepared by reacting ammonia gas in the alcohol phase, but there are still long reaction times, and the reaction is not easy to control, the catalytic efficiency is low, the solvent consumption is large and the recovery is difficult, and the inorganic salts such as ammonium chloride produced in the reaction pass through the solvent. It can only be removed by repeated recrystallization or electrodialysis separation with water, and the post-treatment is troublesome, and the amount of waste brine is large

[0005] Patent document US5155264 and CN1080632 report take chloroacetic acid, ammonia as raw material, paraformaldehyde is catalyst, solvent is the glycine preparation method of alcohol phase, although this method avoids producing ammonium chloride, iminodiacetic acid and nitrogen triacetic acid, but catalyst The dosage is large, the glycine product is difficult to separate from the catalyst, and multi-step alcohol washing is required to obtain a product with a higher content, which has the disadvantages of large solvent loss and low equipment loading factor