Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (8): 1456-1464.doi: 10.3866/PKU.WHXB201406091

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Selective Hydrogenation Mechanism of Cinnamaldehyde on Au(111) Surface

XIAO Xue-Chun, SHI Wei, NI Zhe-Ming   

  1. Laboratory of Advanced Catalytic Materials, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, P. R. China
  • Received:2014-03-24 Revised:2014-06-09 Published:2014-07-18
  • Contact: NI Zhe-Ming E-mail:jchx@zjut.edu.cn

Abstract:

The adsorption behavior and selective hydrogenation reaction mechanisms (C=O addition, C=C addition, and 1,4-conjugate addition) of cinnamaldehyde on an Au(111) surface were investigated by density functional theory combined with a periodic slab model. The adsorption energies of various adsorption models were obtained to determine the preferred adsorption configuration. The calculated results indicate that the most stable adsorption configuration involved the C=O and C=C double bond adsorbed on the Au(111) surface, with an average adsorption energy of 140.0 kJ·mol-1. The transition states of each elementary reaction for all possible reaction mechanisms were also located. Comparison of the activation energy barriers revealed hydrocinnamaldehyde (HCAL) to be the most likely selective hydrogenation product of cinnamaldehyde on an Au(111) surface. In addition, the 1,4- conjugate addition mechanism, which generates 3-phenyl-1-propen-1-ol (ENOL) that readily tautomerizes to HCAL, required less activation energy than did the C=C direct addition mechanism. The dominant reaction pathway involved an O atom of cinnamaldehyde preferentially hydrogenating to generate a more stable allyl intermediate. Another H atom then added to a C atom directly connected to the phenyl ring of the allyl intermediate to yield ENOL. Finally, ENOL tautomerized to HCAL. Throughout the process, the generation of ENOL is the rate-determining step, for which the highest activation energy barrier was required.

Key words: Au(111) surface, Cinnamaldehyde, Density functional theory, Hydrocinnamaldehyde, Selective hydrogenation mechanism

MSC2000: 

  • O641