Continuous synthesis method of glycine methyl ester hydrochloride

Abstract

A continuous synthesis method of glycine methyl ester hydrochloride specifically includes the steps that glycine and anhydrous methanol are added into a mixing kettle, and under the stirring condition, hydrogen chloride gas is introduced until the glycine is completely dissolved; the uniformly mixed material is continuously pumped into a reaction kettle, the temperature of a reaction system is maintained to be 55-60 DEG C, a seed crystal heat preservation reaction is added, the stirring speed is controlled, and continuously separated crystals are deposited at the bottom of the reaction kettle;then the crystals are subjected to centrifugation, washing and drying to obtain white crystal powder, and centrifugal mother liquor is pumped into the mixing kettle for cyclic utilization; while thecontinuous feeding reaction is carried out, a negative pressure system of 0.02-0.04 MPa is built in the reaction kettle, and water generated by the reaction is discharged by excessive methanol in thesystem during the reaction. According to the method, the process route is simple, the utilization rate of the reaction equipment is high, the product yield can reach 93% or above, the purity is higherthan 98%, no waste is generated, and automatic industrial production is easy to realize.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a continuous synthesis method of glycine methyl ester hydrochloride. Background technique [0002] Amino acid methyl ester is one of amino acid derivatives. It is a bifunctional compound containing ester group and amino group. It has very important applications in the fields of peptide synthesis, medicinal chemistry, and agriculture, and is an important organic synthesis intermediate. Because amino acid methyl ester itself is easy to condense, has poor stability and is difficult to separate and purify, it is usually made into amino acid hydrochloride with relatively stable chemical properties for preservation and storage. The synthesis methods of amino acid methyl ester hydrochloride include hydrogen chloride method, thionyl chloride method, concentrated sulfuric acid method, p-toluenesulfonic acid method and benzenesulfonic acid method. The earliest hydrogen chloride catalytic m...

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Problems solved by technology

As one of the important members of amino acid methyl ester hydrochloride, glycine methyl ester hydrochloride is a white crystalline powder at room temperature, easily soluble in water, slightly soluble in ethanol, easy to absorb moisture when placed in the air, and can be used for the preparation of various drugs Intermediate, the synthesis process mostly adopts the intermittent production method of hydrogen chloride single-pot type, that is, using glycine, anhydrous methanol and dry hydrogen chloride gas as raw materials, heating and stirring until the system is completely dissolved, and transferring the reaction solution to the crystallization pot while it is hot, Cooling crystallization and filtration to obtain the finished product of glycine methyl ester hydrochloride, this method has technical defects such as long reaction cycle, low equipment utilization rate, low product yield, unstable quality, etc., and the production cost is high, which is not conducive to current energy saving and consumption reduction. Effective Implementation of Policy

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