METHOD AND SYSTEM FOR CONTINUOUS PRODUCTION OF LACTIDE BY MEANS OF STEPWISE CONTROL Russian patent published in 2025 - IPC C07D319/12 B01D3/10 C08G63/08 

FIELD: chemistry.

SUBSTANCE: present invention relates to biodegradable materials, specifically to a method and system for continuous production of lactide by stepwise control. Method includes a step of reacting a lactic acid oligomer and a depolymerisation catalyst in a first depolymerisation reaction unit to obtain a first liquid-phase material, a step of circulating the first liquid-phase material in the second depolymerisation reaction unit until the molecular weight of liquid exceeds 6,000. Further, the obtained second liquid-phase material is subjected to a circulation step in a third depolymerisation reaction unit for reaction until the molecular weight of the liquid-phase material exceeds 10,000. Collection of gas-phase crude lactide is carried out from the first, second and third reaction units of depolymerisation, and then it is purified.

EFFECT: invention provides high-efficiency depolymerisation of lactic acid oligomer, reduces degree of racemization of lactide, reduces probability of substrate coking and carbonisation, and also provides stability of system during the whole reaction process.

29 cl, 1 dwg, 10 ex