Microwave irradiation: A novel method for rapid synthesis of D,L-lactide

D,L-Lactide with a yield of about 36% was synthesized from D,L-lactic acid by the addition of SnCl2 and Cat-A as catalyst under continuous microwave irradiation in less than 1 h. In order to gain a higher yield, the viscosity-average molecular weight of the oligomer was preferably over 3 000 g.mol(-1), and the microwave power in the depolymerization process was chosen for 200 W with 100 g Of D,L-lactic acid. On comparison 250 with conventional heating in the same experimental conditions, no non-thermal effect of a microwave irradiation was revealed.