Ru-B/MIL-53(Al_xCr_1)催化剂在苯部分加氢反应中的催化性能  

Study on Ru-B/MIL-53(Al_xCr_1) Catalysts for Partial Hydrogenation of Benzene to Cyclohexene

作　　者：窦镕飞 谭晓荷 范义秋 裴燕[1] 乔明华[1] 范康年[1] 孙斌[2] 宗保宁[2] 

机构地区：[1]复旦大学化学系上海市分子催化和功能材料重点实验室,上海200433 [2]中国石化石油化工科学研究院催化材料与反应工程国家重点实验室,北京100083

出　　处：《化学学报》2016年第6期503-512,共10页Acta Chimica Sinica

基　　金：国家重点基础研究发展规划项目(No.2012CB224804);国家自然科学基金(No.21373055);上海市科委科技基金(No.08DZ2270500);北京高能所同步辐射实验室开放课题及中石化技术开发课题(S411063)资助~~

摘　　要：金属-有机骨架材料不仅比表面积大、孔隙率高、孔道规则,而且化学性质和结构性质多样、可调,所以在近年来受到了研究者的广泛关注.合成了MIL-53(Al)、MIL-53(Cr)及新颖的含有二元配位金属的MIL-53(Al_xCr_1)(x=1,2,3,4)材料,以此为载体采用浸渍-化学还原法制备了Ru-B/MIL-53催化剂,考察了它们在苯部分加氢制环己烯反应中的催化性能.催化剂评价结果表明,Al/Cr比不仅影响Ru-B/MIL-53催化剂上的初始反应速率(r0),也影响环己烯的初始选择性(S0).一般而言,高Al含量的MIL-53作为载体对r0有利,而含有二元配位金属的MIL-53作为载体时,S0高于仅有单一配位金属的MIL-53载体.在环己烯选择性最高的Ru-B/MIL-53(Al_3Cr_1)催化剂上,r0和S0分别为9.2 mmol/(min·g)和71%.采用多种手段,对环己烯选择性差异最为显著的Ru-B/MIL-53(Al_3Cr_1)和Ru-B/MIL-53(Cr)催化剂的物化性质进行了对比研究,发现二者Ru-B纳米粒子的化学组成、电子性质、微观结构接近,但前者的活性表面积大于后者,Ru-B粒子的尺寸更小,分散更加均匀,且金属-载体作用更强.更小的Ru-B粒径不仅能够提供更多的活性位,而且也有利于环己烯选择性的提高.通过对反应条件进行优化,在180℃和5.0 MPa H_2压力下,以100mL乙醇胺为修饰剂时,在Ru-B/MIL-53(Al_3Cr_1)催化剂上可得环己烯得率29%的结果.Metal-organic frameworks （MOFs） have attracted enormous research interests not only because of their merits such as high specific surface area, high porosity, and regular pore channels, but also due to their peculiarities of extremely abundant chemical and structural diversity and tunability. In this work, we synthesized MIL-53（Al） and MIL-53（Cr） containing one coordination metal and the novel MIL-53（AlxCr1）（x= 1, 2, 3, and 4） MOFs containing two coordination metals as the supports for the Ru-B/MIL-53 catalysts, which were prepared by the facile impregnation-chemical reduction method. In the challenging partial hydrogenation of benzene to cyclohexene, it is revealed that the Al/Cr ratio had pronounced influences on both the initial hydrogenation rate （r0） and the initial selectivity to cyclohexene （S0）. In general, MIL-53 containing a higher fraction of Al affords a higher r0, while MIL-53 containing both Al and Cr is conducive to a higher So than either MIL-53（Al） or MIL-53（Cr） containing only one coordination metal. On the Ru-B/MIL-53（AA3Crl） catalyst exhibiting the highest selectivity to cyclohexene, the ro and S0 were 9.2 mmol/（min-g） and 71%, respectively. The best Ru-B/MIL-53（Al3Crl） catalyst and the Ru-B/MIL-53（Cr） catalyst displaying the lowest selectivity to cyclohexene were comparatively characterized to have an insight into the difference in their catalytic performance. It is found that while both catalysts had similar Ru/B molar ratio, electronic property, and microstructure, the Ru-B/MIL-53（Al3Cr0 catalyst had higher active surface area （Sact）, smaller and more highly dispersed Ru-B nanopartieles （NPs）, and stronger metal-support interaction than the Ru-B/MIL-53（Cr） catalyst. The smaller Ru-B NPs could not only provide more active sites for the hydrogenation of benzene, but also be beneficial to the formation of eyelohexene. By further optimization of the reaction conditions, at 180 ℃, H2 pressure of 5.0 MPa, and using 100 μL of et

关 键 词：二元金属-有机骨架 钌 苯 环己烯 部分加氢 

分 类 号：O621.251[理学—有机化学]