METHOD FOR PREPARING LACTIDE

FIELD: chemical technology. ^ SUBSTANCE: Invention relates to synthesis of lactide (lactic acid dimer). Method is carried out by the liquid-phase depolymerization reaction of lactic acid oligomers in the presence of tin compounds at enhanced temperature and under normal pressure. Lactide is removed with gaseous substances flow based on continuous feeding inert gaseous substance to reaction mass followed by isolation of lactide from flow by absorption using a solvent. Method involves continuous feeding inert organic substance flow or flow of liquid organic substance to the reaction mass. After separation the main amount of gaseous lactide and inert gaseous substance from the flow this flow of gaseous substance outputting from reactor is recovered into reactor in the complete volume. Invention provides enhancing yield of lactide and decreasing the consumption norm of gaseous substance. Synthesized lactide is used for synthesis of biodegradable polymeric materials used as covers and containers for foodstuffs and in medicinal industry also. ^ EFFECT: improved method of synthesis. ^ 2 cl, 1 dwg, 1 tbl, 9 ex