钛酸铅催化碳酸二甲酯与苯酚的酯交换反应

PbTiO_3 Catalyst for Transesterification of Dimethyl Carbonate with Phenol

用水热法制备了焦绿石型的催化剂Pb2Ti2O6,并用其催化碳酸二甲酯与苯酚的酯交换反应。研究了制备Pb2Ti2O6所需前驱物配比和焙烧温度对催化剂性能的影响以及催化剂对酯交换反应的作用效果。通过XRD、NH3-TPD、SEM等表征手段对催化剂的结构、表面酸性、形貌进行了表征。表征显示,在300℃焙烧条件下,焦绿石型Pb2Ti2O6开始发生晶型转变,表面酸性消失;焙烧至500℃得到钙钛矿型PbTiO3。实验表明,钙钛矿型PbTiO3较焦绿石型Pb2Ti2O6对酯交换反应有更好的活性。同时考察了钙钛矿型PbTiO3催化剂的使用寿命,发现催化剂在使用4次后,酯交换产物甲基苯基碳酸酯(MPC)和碳酸二苯酯(DPC)收率分别从16.9%和8.9%下降为7.1%和3.3%。

Pyrochlore Pb2Ti2O6 was synthesized as a catalyst for transesterification of dimethy carbonate（DMC） with phenol through hydrothermal methods.The impact of the molar ratio of precursor and calcination temperature of pb2Ti2O6 on this reaction was investigated.XRD,NH3-TPD,and SEM were employed for catalyst characterization.It showed that phase transition occured and surface acid disappered at 300℃.Perovskite PbTiO3 was obtained at 500℃. The activity of Perovskite PbTiO3 was higher than Pyrochlore Pb2Ti2O6.At the same time,the reusability of the catalysts was researched.After PbTiO3 was reused four times,the yield of MPC and DPC was reduced from 16.9% and 8.9% to 7.1% and 3.3%,respectively.