Synthesis of ZSM-48 zeolites and their catalytic performance in C4-olefin cracking reactions
Synthesis of ZSM-48 zeolites and their catalytic performance in C4-olefin cracking reactions
复制标题
DOI：
10.1016/j.apcata.2005.10.022
复制
发表时间：
2006-01
影响因子：
5.5
通讯作者：
Guoliang Zhao;J. Teng;Yahong Zhang;Zaiku Xie;Y. Yue;Qingling Chen;Yi Tang
中科院分区：
文献类型：
--
作者：
Guoliang Zhao;J. Teng;Yahong Zhang;Zaiku Xie;Y. Yue;Qingling Chen;Yi Tang
在Na2O-SiO_2-Al_2O_3-H_2N(CH_2)_6NH_2(HDA)水热体系中合成了一系列SiO_2/Al_2O_3比的ZSM-48沸石样品。用X射线粉末衍射、氮气吸附、扫描电子显微镜、程序升温氨解吸、热重分析和化学分析等手段对样品进行了表征。OH-−/SiO_2和SiO_2/Al_2O_3是形成纯ZSM-48的关键因素。在这些ZSM-48分子筛上进行了C4-烯烃裂解反应制丙烯。与目前使用的HZSM-5沸石相比，HZSM-48沸石对目标烯烃表现出了更好的选择性，特别是对低SiO_2/Al_2O_3比的烯烃。HZSM-48和HZSM-5分子筛对C4-烯烃裂解反应的催化性能差异主要是由于它们的酸性不同所致。考察了反应温度和液时空速对HZSM-48催化剂催化性能的影响。并对C4-烯烃裂化反应中HZSM-48分子筛失活的原因进行了探讨。
ZSM-48 zeolite samples with a series of SiO2/Al2O3ratios were synthesized in the hydrothermal system of Na2O–SiO2–Al2O3–H2N(CH2)6NH2(HDA). The samples were characterized by X-ray powder diffraction, N2adsorption, scanning electron microscopy, temperature-programmed desorption of ammonia, thermo-gravimetric analysis and chemical analysis. Both the OH−/SiO2and SiO2/Al2O3ratios played key roles for the formation of pure ZSM-48. C4-olefin cracking reactions were carried out on these ZSM-48 zeolites to produce propylene. Compared with currently used HZSM-5 zeolite, HZSM-48 zeolite exhibits a more excellent selectivity for the aimed olefins, especially for those with lower SiO2/Al2O3ratios. The difference of catalytic performance of HZSM-48 and HZSM-5 zeolites for the cracking of C4-olefin can be attributed to their different acidities. The influences of reaction temperature and liquid hour space velocity on the catalytic performance of the HZSM-48 catalysts were investigated. The reasons for the deactivation of HZSM-48 zeolite in C4-olefin cracking reactions were also studied.