Magnesium catalyst and method for recovering lactide by depolymerizing random polylactic acid

The invention discloses a magnesium catalyst and a method for recovering lactide by depolymerizing random polylactic acid, and belongs to the technical field of polylactic acid degradation. The problems that existing polylactic acid degradation mostly aims at PLLA, optically pure L-lactide is obtained through recovery, and degradation for random polylactic acid is lacked are solved. Under the catalysis of the magnesium complex and under the heating condition, the reduced pressure distillation mode is used for achieving degradation of the random polylactic acid to obtain the racemic lactide, so that cyclic utilization of the waste random polylactic acid is achieved, the blank of catalytic degradation of the random polylactic acid is filled up, and more possibilities are provided for application of the polylactic acid. And the magnesium complex catalyst adopted by the invention only needs to be prepared in situ in the depolymerization process, so that the production cost is lower, and the method is suitable for