纳米氧化锌高效催化左旋丙交酯制备及工艺研究

Preparation and Technology of L-lactide Catalyzed by Nano-sized Zinc Oxide

以纳米氧化锌为催化剂,通过两步制备法:乳酸(LA)低聚物制备和低聚物裂解环化,制备左旋丙交酯(L-LA)。进一步采用红外光谱、核磁共振、差式扫描量热法对所制备L-LA样品进行深入表征。研究旨在优化丙交酯的制备工艺条件以提高产品收率,因而详细探究了催化剂含量、脱结合水反应温度、反应时间、馏出温度等参数对L-LA收率的影响。结果显示,催化剂含量为0.2%,反应温度为120℃,反应5 h,馏出温度为240℃时为最佳的制备工艺条件,并以此对反应的机理进行讨论。

L-lactide was synthesized through two steps by using nanosized zinc oxide as catalyst, the synthesis of polylactic acid oligomer and the pyrolysis cyclization of oligomer.The obtained L-lactide were studied by Fourier transform infrared spectrometer(FTIR),proton nuclear magnetic resonance(;H NMR)and differential scanning calorimetry(DSC),to analyze the chemical structure of L-lactide and its purity.Therefore, the effects of catalyst concentration, reaction temperature and reaction time of debonding water, distillation temperature and other parameters on the yield of L-lactide were studied, and the reaction mechanism was analyzed.The optimum yield is obtained at catalyst concentration of 0.2%,reaction temperature of 120 ℃,the reaction time of 5 h, and the distillation temperature of 240 ℃.