新型催化剂Mo配合物催化乙烯加氢反应的机理  

Reaction mechanisms of ethylene hydrogenation catalyzed by MoX2

作　　者：任小花[1] 范国兰 许宏宇 崔兆杰[3] REN Xiao-hua;FAN Guo-lan;XU Hong-yu;CUI Zhao-jie(Shandong Peninsula Engineering Research Center of Comprehensive Brine Utilization,Weifang University of Science and Technology,Shouguang 262700,China;Jinan Environmental Research Institute,Jinan 250100,China;School of Environmental Science and Engineering,Shandong University,Jinan 250100,China)

机构地区：[1]潍坊科技学院山东半岛卤水资源高值化绿色化综合利用工程技术研发中心,山东寿光262700 [2]济南市环境保护科学研究院,山东济南250100 [3]山东大学环境科学与工程学院,山东济南250100

出　　处：《分子科学学报》2018年第4期318-323,共6页Journal of Molecular Science

基　　金：山东省科技发展计划项目(2014GSF117013)

摘　　要：采用密度泛函B3LYP方法,对新型催化剂MoX2（X=O,S,Se）催化C2H4加氢反应机理进行了研究.结果表明MoX2对C2H4加氢有较好的催化作用,主要包括2种反应途径.以MoS2为例,先活化H—H键再与C2H4反应（先形成MoX2-H2中间体,R1）和先活化CC键再与H2反应（先形成MoX2-C2H4中间体,R2和R3）.第二种途径包括H2从催化剂同侧（R3）和异侧（R2）攻击C2H4.路径R1和R3活化能比无催化剂条件下低311.62-318.85kJ/mol,具有明显的能量优势,其中,路径R3活化能最低,为24.33kJ/mol,表明该反应最容易进行.电子结构分析表明MoX2能够削弱H—H和C=C的强度,降低H2和C2H4的轨道能级,使C2H4加氢更容易进行.The reaction mechanisms of ethylene hydrogenation catalyzed by MoX2（X=O,S,Se）were investigated by density functional theory（DFT）at B3 LYP level.The calculated results showed that MoX2 complexes were promising catalysts for ethylene hydrogenation.Taking MoS2 as an example,it included two reaction ways：IM1（MoX2-H2）＋C2H4 and IM2（MoX2-C2H4）＋H2.The second way was divided into IM2＋H2→TS2→IM4 and IM2＋H2→IM3→TS3→IM4.The activation energies of the first way and IM2＋H2→IM3→TS3→IM4 were 311.62 to 318.85 kJ/mol lower than the original reaction（without catalyst）.Importantly,the activation energy of the path IM2＋H2→IM3→TS3→IM4 is lowest（24.33 kJ/mol）,indicating the reaction is easiest to occur.Additionally,Natural bond orbital analysis suggested that MoX2 can weaken the H—H/C=C bond strength by forming MoX2-H2/C2H4 intermediates,and can decrease the energy of the orbital level,which facilitated the ethylene hydrogenation reaction.

关 键 词：密度泛函理论 MoX2 乙烯加氢 反应机理 轨道能级 

分 类 号：O643[理学—物理化学]