Effects of Support Acidity on the Catalytic Performance of Mo/HZSM-5-Al2O3 Catalysts in Olefin Metathesis
Effects of Support Acidity on the Catalytic Performance of Mo/HZSM-5-Al2O3 Catalysts in Olefin Metathesis
复制标题
载体酸度对Mo/HZSM-5-Al2O3催化剂烯烃复分解反应性能的影响
DOI：
10.3724/sp.j.1088.2011.10744
复制
发表时间：
2011-11
影响因子：
16.5
通讯作者：
Xu Longya
中科院分区：
文献类型：
--
作者：
Zhang Dazhou;Li Xiujie;Liu Shenglin;Zhu Xiangxue;Xin Wenjie;Xe Sujuan;Zeng Peng;Xu Longya
在固定床反应器中制备并评价了具有不同硅铝比（12、42和213）的hzsm-5的Mo/hzsm-5-al 2 o3催化剂样品。考察了载体酸性变化对Mo/HZSM-5-Al 2 O3催化剂在乙烯和2-丁烯歧化反应中催化性能的影响。NH3程序升温脱附和吡啶红外光谱表明，载体酸性的不同导致Mo物种在复合载体上的不同锚定方式。由于Mo/HZSM-5-Al_2 O_3（Si/Al = 12）催化剂的酸性密度较高，催化剂失活较快。对于Mo/HZSM-5-Al 2 O3（Si/Al = 213），紫外-可见漫反射光谱和H-2程序升温还原结果表明，更多的Mo物种以八面体形式分散在Al 2 O3上，而位于沸石孔道中的Mo物种以（Mo 2 O 5）（2+）团簇形式存在。这种分布与Mo/HZSM-5-Al 2 O3（Si/Al = 213）上的低复分解活性和诱导期的出现有关。Mo/HZSM-5-Al_2 O_3（Si/Al = 42）催化剂的催化活性和反应稳定性最好。这是由于其适宜的酸度和钼物种在载体上的最佳分布。
Mo/hzsm-5-al2o3 catalyst samples, where the hzsm-5 had different si/al ratios (12, 42, and 213), were prepared and evaluated in a fixed-bed reactor. effects of support acidity changes on the catalytic performance of mo/hzsm-5-al2o3 in the metathesis of ethene and 2-butene to propene were investigated. nh3 temperature-programmed desorption and pyridine infrared spectra revealed that the differences in support acidity led to the different anchoring modes of mo species on the composite supports. quick deactivation phenomena were observed on mo/hzsm-5-al2o3 (si/al = 12) due to the high acidity density of the catalyst. for mo/hzsm-5-al2o3 (si/al = 213), more mo species dispersed on the alumina in octahedral form and those locating in the zeolite channels existed in the state of (mo2o5)(2+) clusters evidenced by ultraviolet-visible diffuse reflectance spectroscopy and h-2 temperature-programmed reduction results. such distribution was linked with the low metathesis activity and the appearance of the induction period on mo/hzsm-5-al2o3 (si/al = 213). mo/hzsm-5-al2o3 (si/al = 42) sample demonstrated the best catalytic activity and reaction stability among the three samples. this was attributed to its suitable acidity amount and optimal distribution of mo species on the support.