Preparation method of N, N-dimethylglycine for industrial production

Abstract

The invention discloses a preparation method of N, N-dimethylglycine for industrial production. The preparation method comprises the following steps of S1, chloroacetic acid solution preparation: adding chloroacetic acid into water at a normal temperature to obtain a chloroacetic acid solution, S2, reaction of the chloroacetic acid solution and dimethylamine: adding the chloroacetic acid solution into a dimethylamine agueous solution according to a more ratio of chloroacetic acid to dimethylamine of 1: 2.5 to 1: 5, controlling a temperature in 20-70 DEG C, and then carrying out a thermal insulation reaction process at the temperature of 20-70 DEG C for 2-5h, S3, redundant dimethylamine removal: removing unreacted dimethylamine after the thermal insulation reaction, and S4, condensation crystallization, centrifugation and drying: concentrating the solution obtained by the step S3 to obtain a lot of white crystals, carrying out cooling to a temperature of 25 DEG C, and carrying out centrifugation and drying. The preparation method adopts the easily-available and cheap raw materials, has simple processes, is convenient for operation, has no purification difficulty and is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a preparation method of a pharmaceutical chemical intermediate, in particular to a preparation method of N,N-dimethylglycine suitable for industrial production. Background technique [0002] At present, N,N-dimethylglycine can be used as a drug to treat depression, improve human immunity, and enhance human tolerance. The methyl group in the structure has the function of transmethylation, which can be used to resist tumors and cancers, and can be widely used in the synthesis of anticancer drugs. N,N-Dimethylglycine can be used as a skin penetration enhancer and cosmetic additive due to its strong water absorption. At the same time, the antioxidant and non-toxic properties of N,N-dimethylglycine can be used as an antioxidant in food. [0003] The methods for preparing N,N-dimethylglycine in the past include: [0004] 1. Prepare N,N-dimethylglycine by reacting sodium cyanide, dimethylamine, sodium bisulfite and formaldehyde. Th...

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Problems solved by technology

[0005] 2. Formaldehyde reacts with glycine to prepare N,N-dimethylglycine in formic acid environment. This method is not easy to obtain pure N,N from formic acid system. Dimethylglycine;

[0006] 3. Using glycine and formaldehyde as raw materials in the presence of palladium / carbon catalyst to synthesize N,N by hydrogenation under normal pressure. Dimethylglycine, the catalyst for this method is too expensive;

[0007] 4. Dimethylamine reacts with hydroxyacetonitrile, and then hydrolyzes to obtain N,N-dimethylglycine. This method also uses cyanide, which seriously pollutes the environment;

[0008] 5. Chloroacetic acid reacts with sodium hydroxide to generate sodium chloroacetate, and sodium chloroacetate reacts with dimethylamine. After desalting by electrodialysis, it is recrystallized in ethanol to obtain N,N-dimethylglycine. Acetic acid first reacts with sodium hydroxide. Because sodium hydroxide is too alkaline, it is easy to hydrolyze chloroacetic acid to generate sodium glycolate, so that the yield is low, and the sodium chloride generated in the reaction process is not easy to remove. To use electrodialysis, the cost of a complete set of electrodialysis equipment in industrial production is too high, and the energy consumption is too high. After electrodialysis, some N, N. Dimethylglycine will enter the concentrated water through the membrane, reducing the yield, and the yield is only about 60%.

None of the above methods are suitable for industrial production