科研之友
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摘要
Density functional theory (DFF) was employed to investigate the dimerization of ethene over acidic zeolites with a 5T cluster model simulating zeolite. At the B3LYP/6-31.1+G(3df, 2p) level, the activation energy was obtained with a zero point energy (ZPE) correction. It was found that the process of the dimerization of ethene can be divided into three steps: the chemical adsorption of first ethene molecule, the physical adsorption of second ethene molecule and the dimerization reaction. The reaction proceeds by ethene chemical adsorption to form the surface ethoxide and the C-C bond formation between the ethoxide and the second ethene molecule to form the butoxide product. The calculated reaction energy barriers of ethene chemical adsorption and dimerization reaction are 108 and 149 kJ center dot mol(-1), respectively. The obtained activation barrier of beta-scission of 1-butene is 217 kJ center dot mol(-1) in the reverse reaction of ethene dimerization.
- 出版日期2007-12
- 单位北京化工大学
