Method for obtaining lactide

摘要

Processes for producing lactide from lactic acid oligomers are described herein. The processes generally include heating a lactic acid oligomer in the presence of a catalyst at a temperature of between 150° C. and 300° C. under a pressure of less than 0.01 MPa to form a lactide; distilling the lactide; and condensing and recovering the lactide, wherein the catalyst is a metal salt of the phosphite anion PO33- in which the metal is selected from the group consisting of tin, aluminum, zinc, titanium and zirconium.