The promoting effect of introducing Zn into nano-ZSM-5 zeolites by conventional impregnation method and isomorphous substitution on the performance of 1-hexene aromatization was investigated. The nano-ZSM-5 zeolite wa...The promoting effect of introducing Zn into nano-ZSM-5 zeolites by conventional impregnation method and isomorphous substitution on the performance of 1-hexene aromatization was investigated. The nano-ZSM-5 zeolite was synthesized by a seed-induced method without organic templates. The Zn-modified nano-ZSM-5 zeolite catalysts, xZ n/HNZ5 and y Zn/Al-HNZ5, were prepared by the conventional impregnation method and isomorphous substitution, respectively. The structure, chemical composition and acidity of the catalysts were characterized by XRD, XRF, N2 adsorption, SEM, NH3-TPD and Py-IR, while the catalytic properties were evaluated at 480 °C and a weight hourly space velocity（WHSV） of 2.0 h-1 in the aromatization procedure of 1-hexene. Compared with xZ n/HNZ5, y Zn/Al-HNZ5 exhibited smaller particles and higher dispersion of Zn species, which led to greater intergranular mesopore and homogeneous acidity distribution. Experimental results indicated that the synergy effect between the Brnsted and Lewis acid sites of the isomorphously substituted nano-ZSM-5 zeolites could significantly increase aromatics yield and improve catalytic stability in the 1-hexene aromatization.展开更多
分别以二正丁胺(DBA)、拟薄水铝石、磷酸和硅溶胶为模板剂、铝源、磷源和硅源,通过水热合成法,制备出纯相的SAPO-41分子筛。采用XRD、氮气物理吸附、29Si MAS NMR、SEM和吡啶红外(Py-IR)等分析表征手段,考察了DBA用量和晶化时间对SAPO-4...分别以二正丁胺(DBA)、拟薄水铝石、磷酸和硅溶胶为模板剂、铝源、磷源和硅源,通过水热合成法,制备出纯相的SAPO-41分子筛。采用XRD、氮气物理吸附、29Si MAS NMR、SEM和吡啶红外(Py-IR)等分析表征手段,考察了DBA用量和晶化时间对SAPO-41分子筛的晶体结构、孔结构、分子筛骨架中Si原子分布、形貌以及B酸中心强度的影响。降低DBA用量会减弱AFO拓扑结构的导向能力,延长晶化时间不仅有利于AFO拓扑结构的生成,而且有利于分子筛结晶度提高。展开更多
基金Project(21276067)supported by the National Natural Science Foundation of China
文摘The promoting effect of introducing Zn into nano-ZSM-5 zeolites by conventional impregnation method and isomorphous substitution on the performance of 1-hexene aromatization was investigated. The nano-ZSM-5 zeolite was synthesized by a seed-induced method without organic templates. The Zn-modified nano-ZSM-5 zeolite catalysts, xZ n/HNZ5 and y Zn/Al-HNZ5, were prepared by the conventional impregnation method and isomorphous substitution, respectively. The structure, chemical composition and acidity of the catalysts were characterized by XRD, XRF, N2 adsorption, SEM, NH3-TPD and Py-IR, while the catalytic properties were evaluated at 480 °C and a weight hourly space velocity（WHSV） of 2.0 h-1 in the aromatization procedure of 1-hexene. Compared with xZ n/HNZ5, y Zn/Al-HNZ5 exhibited smaller particles and higher dispersion of Zn species, which led to greater intergranular mesopore and homogeneous acidity distribution. Experimental results indicated that the synergy effect between the Brnsted and Lewis acid sites of the isomorphously substituted nano-ZSM-5 zeolites could significantly increase aromatics yield and improve catalytic stability in the 1-hexene aromatization.
文摘分别以二正丁胺(DBA)、拟薄水铝石、磷酸和硅溶胶为模板剂、铝源、磷源和硅源,通过水热合成法,制备出纯相的SAPO-41分子筛。采用XRD、氮气物理吸附、29Si MAS NMR、SEM和吡啶红外(Py-IR)等分析表征手段,考察了DBA用量和晶化时间对SAPO-41分子筛的晶体结构、孔结构、分子筛骨架中Si原子分布、形貌以及B酸中心强度的影响。降低DBA用量会减弱AFO拓扑结构的导向能力,延长晶化时间不仅有利于AFO拓扑结构的生成,而且有利于分子筛结晶度提高。
