【摘要】 采用离子热法在SAPO-5的合成母液中引入黏附SAPO-5微晶的HZSM-5,180℃晶化72h,制备得到了HZSM-5/SAPO-5复合分子筛,采用XRD、SEM、NH3-TPD和Py-IR等手段对分子筛的结构、形貌及酸性进行表征,考察其在异丁烷芳构化反应中的催化性能。结果表明:HZSM-5/SAPO-5复合分子筛为SAPO-5纳米微晶包覆HZSM-5表面的复合结构,由于SAPO-5为弱酸分子筛,SAPO-5包覆在强固体酸催化剂HZSM-5表面可覆盖其外表面的强酸位,使强、弱酸比例下降,有效抑制了HZSM-5强酸位上异丁烷的裂解副反应,强、弱酸协同芳构化作用提高了目标产物BTEX的选择性和反应稳定性。更多还原

【Abstract】 HZSM-5/SAPO-5 composite molecular sieves were synthesized successfully by adding the HZSM-5 into the ionothermal synthetic sol of SAPO-5 and crystallizing at 180℃ for 72 h. XRD, SEM, NH3-TPD and Py-IR were used to characterize the structure, morphology and acidity of the molecular sieves, and the catalytic activity, BTEX selectivity and stability of the HZSM-5/SAPO-5 molecular sieves in isobutane aromatization were investigated. The results showed that the HZSM-5/SAPO-5 molecular sieves were composed of HZSM-5 covered by SAPO-5 nanocrystals, which could decrease the strong acidity, restrain the cracking of iso-butane, and improve the selectivity of BTEX and the stability of catalysts due to the synergetic aromatization of isobutane between strong acid and weak acid.更多还原