Effect of support composition on the structural and catalytic properties of Ru/AlOOH-SiO2 catalysts for benzene selective hydrogenation
Effect of support composition on the structural and catalytic properties of Ru/AlOOH-SiO2 catalysts for benzene selective hydrogenation
复制标题
载体组成对Ru/AlOOH-SiO2苯选择性加氢催化剂结构和催化性能的影响
DOI：
10.1039/c8cy00059j
复制
发表时间：
2018
影响因子：
5
通讯作者：
Xin Zhou
中科院分区：
文献类型：
--
作者：
Gongbing Zhou;Yanlu Dong;Lan Jiang;Daiping He;Ya Yang;Xin Zhou
苯选择加氢制环己烯是近年来在原子经济性、原料易得性和操作简便性等方面备受关注的一项反应，本文以不同Al/Si比的AlOOOH-SiO2复合材料为载体，考察了载体酸性对催化剂性能的影响。采用吸附吡啶的傅里叶变换红外光谱、透射电子显微镜和扩展X射线吸收精细结构光谱等技术对催化剂进行了全面表征。证实了刘易斯酸中心的量随着Al/Si摩尔比的增加而稳定地增加。在苯选择加氢反应中，苯的转化率与酸中心数量呈线性相关，而环己烯选择性则呈火山式变化，最高可达81%。动力学研究表明，刘易斯酸中心对苯加氢和环己烯加氢反应的速率常数均有不同程度的促进作用。由此产生的比率的速率常数演变平行的变化，在环己烯的选择性，这阐明了火山型之间的关系，环己烯的选择性和刘易斯酸位点的量。
Benzene selective hydrogenation to cyclohexene, which has been attracting attention in terms of atomic economy, feedstock accessibility, and operational facilitation, has been investigated on Ru catalysts supported on AlOOH–SiO2 composites with varying Al/Si ratios aiming at unveiling the effect of support acidity. Various techniques such as Fourier transform infrared spectroscopy of adsorbed pyridine, transmission electron microscopy, and extended X-ray absorption fine structure spectroscopy were employed to comprehensively characterize the catalysts. It is confirmed that the amount of Lewis acid sites increased steadily with the increase in the Al/Si molar ratio. In benzene selective hydrogenation, the turnover frequency of benzene linearly correlated with the amount of acid sites, while the cyclohexene selectivity showed a volcano-type trend, achieving a maximum of 81%. Kinetic investigation revealed that the Lewis acid sites promoted the rate constants of both the benzene hydrogenation and cyclohexene hydrogenation steps to inequable extents. The resulting ratios of the rate constants evolved parallel to the variation in the cyclohexene selectivity, which elucidated the volcano-type relationship between the cyclohexene selectivity and the amount of Lewis acid sites.