【摘要】 以新型稀土La-Ti复合氧化物作为催化剂,催化乳酸合成丙交酯.考察了催化剂对反应体系粘度、丙交酯产率、反应时间、反应温度的影响,获得了较佳的反应工艺条件:减压下,70～90℃脱自由水1.5h;随后加入催化剂,用量为乳酸重量的0.8%,缓慢升温到120～140℃进行缩聚反应3～4h;再在170～260℃,保持升温速率为4℃/10min进行裂解.产物纯度和结构分别由Thiele管和红外光谱进行测定.丙交酯粗产率达88.5%,纯产率为40.2%,表明该催化剂具有良好的催化性能.更多还原

【Abstract】 A new rare earth La-Ti compound oxide catalyst to prepare lactide was employed. The effects of catalyst on the viscosity of reaction system, yield of lactide, reaction temperature and time were studied. The optimum synthesis conditions were obtained under reduced pressure, the lactic acid was dehydrated at 70~90 ℃ for 1.5 h; then the catalyst was added 0.8% by weight of the lactic acid and heated up to 120~140 ℃, to condensate for 3~4 h; last keep the increasing rate of the temperature at 0.4 ℃/min in the range of 170~260 ℃. The crude yield of lactide reaches 88.5% and the pure yield is 40.2%. Purity and structure of lactide are characterized by melting point and IR spectrum.更多还原