中孔分子筛SO_4^(2-)/Zr-MCM-41催化裂解聚丙烯反应研究

Study on Catalytic Pyrolysis of Polypropene over SO_4^(2-)/Zr-MCM-41

采用水热合成法制备了不同硅锆比的中孔分子筛Zr-MCM-41,用强酸性基团SO42-对其进行修饰,制得SO42-/Zr-MCM-41中孔分子筛.采用XRD、FT-IR、NH3-TPD及氮气吸附脱附等技术对其结构和酸强度进行表征.通过改变硅锆比、负载不同的酸性基团对Zr-MCM-41的酸性进行调变,并将其用于催化聚丙烯(PP)的裂解反应,结果表明S i/Zr=40的SO42-/Zr-MCM-41具有较好的催化裂解活性.另外,与热裂解以及HZSM-5和Zr-MCM-41为催化剂时PP的裂解反应结果进行了比较,结果证明SO42-/Zr-MCM-41不仅具有较高的裂解转化率,而且具有较高的液体产物收率,适宜于空间位阻较大的PP的催化裂解反应.

Mesoporous Zr-MCM-41 materials of different Si/Zr ratios were synthesized under hydrothermal conditions. Zr-MCM-41 material was impregnated in sulfuric acid to prepare SO4^2-/Zr-MCM-41. The obtained materials were characterized by XRD, FT-IR, N2 adsorption/desorption and NH3-TPD techniques. The acidity of Zr-MCM- 41 was adjusted by changing the molar ratio of Si to Zr and supporting other acidic groups. The results showed that SO4^2-/Zr-MCM-41 of Si/Zr =40 showed better catalytic activity when used as catalyst in the pyrolysis of polypro- pene（PP）. Compared with the results obtained by thermal pyrolysis and by catalytic pyrolysis over HZSM-5 or Zr- MCM-41, higher pyrolysis conversion of PP and higher yield of liquid products were obtained using SO4^2-/Zr-MCM-41 as catalyst. It was showed that SO4^2-/Zr-MCM-41 was especially suitable for the pyrolysis of sterically hindered polymers such as PP.