Chem. J. Chinese Universities ›› 2023, Vol. 44 ›› Issue (2): 20220486.doi: 10.7503/cjcu20220486

• Physical Chemistry • Previous Articles     Next Articles

Theoretical Calculation of Solvent Dependence in Pd-catalyzed Hydrogenation of Furfural

DENG Yuan, WANG Si, FENG Haisong, ZHANG Xin()   

  1. State Key Laboratory of Chemical Resource Engineering,College of Chemistry,Beijing University of Chemical Technology,Beijing 100029,China
  • Received:2022-07-18 Online:2023-02-10 Published:2022-08-29
  • Contact: ZHANG Xin E-mail:zhangxin@mail.buct.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22173003)

Abstract:

The catalytic hydrogenation reaction process of furfural is mainly divided into gas phase, liquid phase and catalytic transfer hydrogenation. Compared with gas-phase hydrogenation of furfural, liquid-phase hydrogenation provides more sustainability and freedom for the reaction, but the mechanism of the solvent-dependent phenomenon on the directional catalytic conversion of furfural is still unclear. For the above problems, this work selected three solvents(methanol, water and cyclohexane) as the research objects, and used the density functional theory method to explore the effect of solvent on the reactivity and selectivity of Pd-catalyzed furfural hydrogenation. The results showed that the solvent could form hydrogen bond network to promote proton shuttle, stabilize reactants, interme- diates and products, and effectively reduce the energy barrier of C=O hydrogenation. Free energy calculations show that the energy barrier for the first step C=O hydrogenation gradually decreases(0.70 eV>0.68 eV>0.44 eV) with decreasing solvent polarity(water>methanol>cyclohexane). During the hydrogenation of furfural mediated by water and methanol, the reaction barriers for the first C=O hydrogenation were further reduced to 0.47 and 0.41 eV. Differential charge density and Bader charge analysis indicated the existence of charge transfer between furfural and Pd catalysts. The projected density of states(PDOS) analysis showed that the addition of the solvent shifted the center of the d-band toward the Fermi level, implying the improved catalytic activity of the Pd catalyst. This work reveals the key role of solvent in regulating the selectivity of furfural catalytic hydrogenation.

Key words: Solvent dependence, Furfural hydrogenation, Pd catalyst, Theoretical calculation

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