Abstract:

Lactide was synthesized under high vacuum using ZnO as catalyst with the addition of stannous octanoate(Sn(Oct)2) at different intervals. The highest temperature of lactide distillation was decreased to 197 ℃. Lactide crystal was characterized by means of IR spectrum and its melting point was measured. The surface tensions of L-lactic acids after dehydration, after dehydration followed with the addition of zinc oxide or addition of both zinc oxide and stannous octanoate were 38.8, 47.0 and 40.3 N/m, respectively. Their viscosities were 43.1049, 59.6774 and 48.9376 mPa·s, respectively. These experimental results showed stannous octanoate can help the cracking of the bond between acyl and oxide in the intermediate and the decrease of surface tension of reaction system.

Key words: Zinc oxide, Stannous octanoate, lactide, yield, the highest distillation temperature