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.