催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (6): 1000-1006.DOI: 10.3724/SP.J.1088.2012.11209

• 研究论文 • 上一篇    下一篇

Cu(111) 面上糠醇加氢生成 2-甲基呋喃的反应机理

夏明玉, 曹晓霞, 倪哲明*, 施炜, 付晓微   

  1. 浙江工业大学化学工程与材料学院, 先进催化材料实验室, 浙江杭州 310032
  • 收稿日期:2011-12-14 修回日期:2012-01-19 出版日期:2012-05-30 发布日期:2012-05-30

Reaction Mechanism for 2-Methylfuran Formation during Hydrogenation of Furfuryl Alcohol Catalyzed by Cu(111) Plane

XIA Mingyu, CAO Xiaoxia, NI Zheming*, SHI Wei, FU Xiaowei   

  1. Laboratory of Advanced Catalytic Materials, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, Zhejiang, China
  • Received:2011-12-14 Revised:2012-01-19 Online:2012-05-30 Published:2012-05-30

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951

被引次数

4

摘要： 采用广义梯度近似的密度泛函理论并结合平板模型的方法, 详细研究了糠醇在 Cu(111) 面上反应生成 2-甲基呋喃的反应历程, 优化了糠醇在 Cu(111) 面的吸附模型, 并采用完全线性同步和二次同步变换的方法, 对三种可能的反应机理中的各反应步骤进行了过渡态搜索. 结果表明, 糠醇主要通过支链上 OH 与 Cu(111) 面相互作用, 易形成 ψCH2 和 ψCH2O 中间体 (ψ 代表呋喃环). 糠醇进一步加氢机理很可能为: 引入的氢物种明显降低了糠醇分解形成的中间体 ψCH2 的活化能, 并促进了它的形成; 中间体 ψCH2 更易从糠醇中获得 H 而生成 2-甲基呋喃. 该过程的控速步骤为 ψCH2O* → ψCHO* + H*, 活化能为 199.0 kJ/mol, 总反应是 2ψCH2OH = ψCH3 + ψCHO + H2O.

关键词: 铜(111) 面, 密度泛函理论, 2-甲基呋喃, 反应机理, 糠醇

Abstract: The reaction mechanism for 2-methylfuran formation during hydrogenation of furfuryl alcohol on Cu(111) plane was investigated by the density functional theory generalized gradient approximation calculations with the slab model. The adsorption energy of furfuryl alcohol was calculated to obtain preferred adsorption sites on Cu(111) plane. Three possible reaction mechanisms were characterized and the reaction potential energy surfaces were computed. The transition states (TSs) were searched with the linear and quadratic synchronous transit (LST/QST) complete search. The results show that the furfuryl alcohol molecule adsorbed on the Cu(111) plane via –OH, and the intermediate ψCH2 and ψCH2O can be obtained by the furfuryl alcohol decomposition. The mechanism for 2-methylfuran formation according to the mechanism C is more probable. The energy barrier of furfuryl alcohol decomposition to form ψCH2 can be significantly reduced by the participation of hydrogen radical. The intermediate of ψCH2 is much easier to obtain the H atom from the furfuryl alcohol, that is the formation routine of the product 2-methylfuran. In the mechanism C, the calculated barrier for the rate-determining step ψCH2O* → ψCHO* + H* is 199.0 kJ/mol. The general reaction is 2ψCH2OH = ψCH3 + ψCHO + H2O.

Key words: Cu(111) surface, densityfunctional theory, 2-methylfuran, reaction mechanism, furfuryl alcohol