辛酸亚锡对氧化锌催化制备丙交酯的影响

用减压蒸馏法合成了丙交酯，在反应的不同时间段加入辛酸亚锡，可使丙交酯最高馏出温度降低至197 ℃。 采用红外光谱表征了丙交酯，测定了反应体系的表面张力和黏度，结果表明，脱自由水后的乳酸、脱自由水后加氧化锌和脱自由水后加氧化锌和辛酸亚锡体系的表面张力分别为38.8、47.0和40.3 N/m；黏度分别为43.1049、59.6774和48.9376 mPa·s。 辛酸亚锡的加入降低了反应体系表观张力和黏度，有利于低聚物结构中酰氧键断裂生成丙交酯。

The Effect of Stannous Octanoate on the Synthesis of Lactide Using ZnO as Catalyst

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.