METHOD FOR PRODUCING A GLYCOLIDE FROM MODIFIED OLIGOMERS OF GLYCOLIC ACID Russian patent published in 2018 - IPC C07D319/12 

FIELD: technological processes.

SUBSTANCE: invention relates to a method for producing a glycolide which is one of initial monomers in ring-opening reactions while producing valuable biodegradable polymers, which are widely used in medicine, pharmaceutics, food industry and modern additive technologies. Method for producing a glycolide from oligomers modified with polyhydric alcohols comprises a process of producing oligomers under the conditions of a polycondensation reaction of a 70 % aqueous solution of glycolic acid and a polyhydric alcohol, taken in a ratio of 17 to 1 by moles, followed by the addition of 1 wt% of an oxide catalyst and the depolymerization of the modified oligomer into glycolide at a temperature of 250 to 255 °C and a pressure of 10–15 mbar. Raw glycolide is purified by three-fold recrystallization from ethyl acetate.

EFFECT: production of high purity glycolide without the use of expensive high-boiling polar solvents.

1 cl, 3 ex