Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (08): 898-902.doi: 10.3866/PKU.WHXB20050815

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DFT Study on Double-bond Isomerization of trans-2-butene Catalyzed by Zeolites

LI Hui-ying; PU Min; CHEN Biao-hua   

  1. Key Laboratory for Science and Technology of Controllable Chemical Reaction of Ministry of Education, Beijing University of Chemical Technology, Beijing 100029
  • Received:2004-12-30 Revised:2005-03-04 Published:2005-08-15
  • Contact: PU Min E-mail:pumin@mail.buct.edu.cn

Abstract: Using density functional theory(DFT), the double-bond isomerization of 1-butene to trans-2-butene over zeolites is investigated with a 3T cluster model simulating zeolite. At the B3LYP/6-31G(d, p) level, the complete geometry optimization and the activation energy calculation are performed with a EZP correction. It is found that the process include three steps, physical adsorption→chemical reaction→physical desorption. Firstly, the OH group of the acidic site of zeolite adsorbs the double-bond of 1-butene and forms a π-complex. Secondly, the double-bond isomerization reaction shows a concerted mechanism and yields the adsorbed trans-2-butene. Lastly, trans-2-butene is produced by desorption and the zeolite active site is restored. The calculated apparent activation energy is 57.1 kJ•mol-1, which is in agreement with the experimental data.

Key words: Zeolite, Butene, Double-bond isomerization, Density functional theory, Transition state