Method for catalytic synthesis of L-pyrroldone carboxylic acid and salt thereof

Abstract

The invention provides a method for producing pyrroldone carboxylic acid and salt thereof. The method comprises the following steps of: adding glutamic acid or univalent salt of glutamic acid and a catalyst in silicone oil or white oil, heating the mixture to the temperature of between 150 and 250 DEG C for cyclized dehydration to obtain the L-pyrroldone carboxylic acid with high yield and high optical purity or univalent salt thereof, wherein the whole process is carried out at the normal pressure; after the reaction lasts for 30 minutes to 6 hours, adding deionized water to dissolve the L-pyrroldone carboxylic acid in the reaction solution, and separating the mixed solution to obtain the target product; and adding corresponding alkali solution to neutrally react with the L-pyrroldone carboxylic acid, and separating the mixed solution to obtain the corresponding solution of L-pyrroldone carboxylic acid salt. In the method, the catalyst is used in the reaction system and the reaction is carried out at the normal pressure, so that the yield and optical purity of the product are improved, and the reaction time is shortened; and the white oil or silicone oil is introduced as a thermal conduction medium, so that the reaction solution can transfer heat more evenly and the reaction temperature is controlled more easily. The invention provides a method for effectively producing the pyrroldone carboxylic acid and the salt of pyrroldone carboxylic acid from the L-glutamic acid and the univalent salt of L-glutamic acid.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for producing L-pyrrolidone carboxylic acid (L-5-pyrrolidone-2-carboxylic acid) and a salt thereof by using L-glutamic acid or a salt as a raw material. Background technique [0002] L-pyrrolidone carboxylic acid is also called L-pyroglutamic acid, and its full English name is Pyrrolidine Carboxylic Acid (PCA for short). It is a cyclic amino acid obtained by dehydration of L-glutamic acid. Its structural formula is: [0003] [0004] L-Pyrrolidone carboxylic acid is a white, odorless crystalline substance with asymmetric carbon atoms in the molecule, has optical activity, is easily soluble in water, insoluble in lower aliphatic alcohols, and insoluble in non-polar organic solvents. PCA is a stable compound when stored under normal conditions. PCA is a major component of natural moisturizing factor (NMF) present in the stratum corneum of human skin. In orga...

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Problems solved by technology

The disadvantage of this method is that the reaction process is carried out under high temperature and high pressure, which has unsafe factors and high requirements for equipment, because the reaction temperature is uniform in the presence of water, and the water will turn into water vapor when it exceeds 100 ° C, which will reduce the efficiency of cyclodehydration. The concentration of the resulting product is also limited

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