物理化学学报 >> 2007, Vol. 23 >> Issue (09): 1447-1450.doi: 10.3866/PKU.WHXB20070926

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氟改变了醇在镍(100)表面上的氧化机理

赵清; 翟光杰; ZAERA Francisco   

  1. 北京理工大学理学院物理系, 北京 100081; 中国科学院空间科学与应用研究中心, 北京 100080; Department of Chemistry, University of California, Riverside 92521, California, USA
  • 收稿日期:2007-04-12 修回日期:2007-05-18 发布日期:2007-09-06
  • 通讯作者: 赵清 E-mail:qzhaoyuping@163.com

Conversion of Alcohol Oxidation on Ni(100) by Fluorine

ZHAO Qing; ZHAI Guang-Jie; ZAERA Francisco   

  1. Department of Physics, College of Science, Beijing Institute of Technology, Beijing 100081, P. R. China; Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100081, P. R. China; Department of Chemistry, University of California, Riverside 92521, California, USA
  • Received:2007-04-12 Revised:2007-05-18 Published:2007-09-06
  • Contact: ZHAO Qing E-mail:qzhaoyuping@163.com

摘要: 利用程序热脱附(TPD)实验研究了2-丙醇和三氟-2-丙醇在Ni(100)表面的吸附和热反应过程. 实验结果表明, 电负性大的氟原子取代丙醇中γ-位氢原子后, 使丙醇从脱氢反应转化为脱水反应. 在这两种化合物的TPD 实验产物中发现, 有以脱水反应生成的烯烃(丙烯, 三氟丙烯), 脱氢反应产生的酮类(丙酮, 三氟丙酮)等分子析出. 实验结果表明, 氟原子取代γ-H后阻止了产生中间产物醇盐的β-H 脱氢反应, 打开了γ-H脱氢反应的通道, 导致烯烃的产生. 在2-丙醇吸附于镍表面的TPD实验中观察到了消去β-H产生丙酮的脱氢反应, 而1,1,1-三氟-2-丙醇在镍表面上经过脱水反应则产生了3,3,3-三氟丙烯.

关键词: 2-丙醇, 三氟-2-丙醇, 热脱附(TPD), Ni(100)

Abstract: The temperature-programmeddesorption(TPD)was used tostudythe adsorptionandthermal decomposition of 2-propanol and trifluoro-2-propanol on clean Ni(100) surface. The products of TPD in both cases were traced for molecular desorption and for the products of dehydration (alkene) and dehydrogenation (ketone) reactions. The results showed that a partial switch from alcohol dehydrogenation to alcohol dehydration was driven by substitution of γ-hydrogen with more electronegative fluorine atoms. The inductive effect exerted by fluorine atoms substituted at the γ position led to a significant inhibition of β-hydride elimination from the alkoxide intermediates, and to the opening of a new γ-hydride elimination channel which eventually ended in alkene formation. While exclusive dehydrogenation to acetone via β-hydride elimination from 2-propoxide surface species was seen with 2-propanol, some dehydration to 3,3,3-trifluoropropene was observed with 1,1,1-trifluoro-2-propanol.

Key words: 2-propanol, Trifluoro-2-propanol, TPD, Ni(100)

MSC2000: 

  • O642