ZrO_2/Ti-MCM-41的制备、表征及催化裂解聚丙烯反应的性能

Preparation,characterization and catalytic performance of ZrO_2/Ti-MCM-41 for polypropylene pyrolysis

采用水热合成法制备了中孔分子筛ZrO2/Ti-MCM-41,通过XRD、N2吸附-脱附、FT-IR、UV-Vis对其进行表征,表明其具有中孔结构,并且随着ZrO2含量的增加,ZrO2/Ti-MCM-41孔道的长程有序性和结晶度有所减弱,直至失去中孔结构。将其应用于聚丙烯(PP)的催化裂解反应,通过考察硅钛比、负载量、反应温度、催化剂用量和反应时间,对ZrO2/Ti-MCM-41催化裂解PP反应的规律进行了研究。结果表明,n(Si):n(Ti)=40,ZrO2负载质量分数为18%的ZrO2/Ti-MCM-41,在反应温度400℃,m(ZrO2/Ti-MCM-41):m(PP)=0.02,反应时间30 min的条件下,PP的转化率可达91.2%,液体产物的收率为83.6%,该结果优于热裂解及传统的HZSM-5小孔分子筛催化剂的催化裂解结果。

Mesoporous ZrO2/Ti-MCM-41 materials were synthesized under hydrothermal conditions, and characterized with XRD, VT-IR, UV-Vis and nitrogen adsorption-desorption. The results showed that the obtained materials were mesoporous molecular sieves with long-range order. The crystallinity of ZrOE/Ti-MCM-41 became poor with the increase of ZrO2. ZrO2/Ti-MCM-41 was used as catalyst in the pyrolysis of PP. The influences of reaction conditions, such as n（Si） ： n（Ti）, content of ZrO2, temperature, dosage of catalyst and reaction time on the pyrolysis results were examined. Under the optimum conditions of n（Si） ; n（Ti）=40, mass percentage of ZrO2 18%, temperature 400℃, re（catalyst） ： m（PP）=0.02 and reaction time 0.5 h, the conversion was 91.2% and the yield of liquid products was 83.6%. Compared with the results obtained by thermal pyrolysis and catalytic pyrolysis on HZSM-5, ZrOE/Ti-MCM-41 was of better catalytic activity and higher yield of liquid products, and was especially suitable for the pyrolysis of sterically hindered polymers, such as PP.