METHOD OF OBTAINING METHYL LACTATE Russian patent published in 2023 - IPC C07C67/08 C07C67/54 C07C69/68 

FIELD: organic synthesis.

SUBSTANCE: invention relates to the production of lactic acid ester - methyl lactate, which can be used as a raw material for the synthesis of lactide and as a “green” solvent in the production of varnishes and additives, as well as a plasticizer in the production of polymer materials. The method of producing methyl lactate involves the continuous esterification of lactic acid with methanol in a flow-type reactor with a fixed bed of a heterogeneous catalyst and purification of methyl lactate from the reaction mass in two distillation columns. A mixture of an aqueous solution of lactic acid with methanol in a molar ratio of 1:15 is fed into a mixer, where it is mixed with argon at a flow rate of 0.3 ml/min. The resulting gas-liquid mixture is sent to a heat exchanger with the temperature maintained at 180°C for evaporation of lactic acid and methanol. The heated vapors of the reaction mass are sent to a flow-type reactor with a fixed layer of silica gel at a temperature of 100–180°C. The resulting vapor products are condensed in a direct refrigerator, and the condensate is collected in a container. In the reactor, heat exchanger, direct cooler and the container, a pressure of 30–160 mbar is maintained, and from the container the reaction products are sequentially separated and purified in two distillation columns, and in the first distillation column high-boiling compounds and lactic acid are separated, in the second distillation column the mixture is purified, and the finished product is obtained.

EFFECT: creation of a method for gas-phase synthesis of methyl lactate from a commercial solution of lactic acid, which makes it possible to reduce the duration of the process.

1 cl, 1 dwg, 6 ex