SCI和EI收录∣中国化工学会会刊

›› 2017, Vol. 25 ›› Issue (3): 294-300.DOI: 10.1016/j.cjche.2016.08.004

• Catalysis, Kinetics and Reaction Engineering • 上一篇    下一篇

Influence factors on activity of Ru-Zn catalysts in selective hydrogenation of benzene

Qi Zhang, Xuhua Yan, Peng Zheng, Zhengbao Wang   

  1. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
  • 收稿日期:2016-04-06 修回日期:2016-08-07 出版日期:2017-03-28 发布日期:2017-04-15
  • 通讯作者: ZhengbaoWang
  • 基金资助:
    Supported by the National Natural Science Foundation of China (no. U1162129).

Influence factors on activity of Ru-Zn catalysts in selective hydrogenation of benzene

Qi Zhang, Xuhua Yan, Peng Zheng, Zhengbao Wang   

  1. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
  • Received:2016-04-06 Revised:2016-08-07 Online:2017-03-28 Published:2017-04-15
  • Supported by:
    Supported by the National Natural Science Foundation of China (no. U1162129).

摘要: Selective hydrogenation of benzene is an atom economic green route to produce cyclohexene. The control of Zn species is the key to the catalytic performance of Ru-Zn catalysts. The influences of ZnO crystals on selective hydrogenation of benzene were explored. A series of Ru-Zn catalysts with different Zn contents and ZnO morphologies were prepared by changing the amount of NaOH in the co-precipitation process. The catalysts were characterized by N2 physisorption, X-ray powder diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), scanning electron microscope (SEM), temperature-programmed reduction (H2-TPR) and Malvern laser particle size analyzer. It is found that with increasing the amount of NaOH, the Zn content first increased then decreased, and the ZnO crystals changed from relatively thicker pyramidal-shaped crystals to slimmer needle-shaped crystals. The catalyst had the highest Zn content (22.1%) and strongest interaction between ZnO crystals and Ru particles at pH 10.6 of the solution after reduction. As a result, it had the lowest activity. The activity of Ru-Zn catalysts is affected by both the Zn content and the interaction between ZnO crystals and Ru particles. The effect of reduction time was also investigated. Prolonging the reduction time caused no significant growth of ZnO crystals but the aggregation of catalyst particles and growth of Ru nanocrystals, thus resulting in the decrease of catalytic activity.

关键词: ZnO morphology, Benzene, Selective hydrogenation, Co-precipitation, Cyclohexene

Abstract: Selective hydrogenation of benzene is an atom economic green route to produce cyclohexene. The control of Zn species is the key to the catalytic performance of Ru-Zn catalysts. The influences of ZnO crystals on selective hydrogenation of benzene were explored. A series of Ru-Zn catalysts with different Zn contents and ZnO morphologies were prepared by changing the amount of NaOH in the co-precipitation process. The catalysts were characterized by N2 physisorption, X-ray powder diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), scanning electron microscope (SEM), temperature-programmed reduction (H2-TPR) and Malvern laser particle size analyzer. It is found that with increasing the amount of NaOH, the Zn content first increased then decreased, and the ZnO crystals changed from relatively thicker pyramidal-shaped crystals to slimmer needle-shaped crystals. The catalyst had the highest Zn content (22.1%) and strongest interaction between ZnO crystals and Ru particles at pH 10.6 of the solution after reduction. As a result, it had the lowest activity. The activity of Ru-Zn catalysts is affected by both the Zn content and the interaction between ZnO crystals and Ru particles. The effect of reduction time was also investigated. Prolonging the reduction time caused no significant growth of ZnO crystals but the aggregation of catalyst particles and growth of Ru nanocrystals, thus resulting in the decrease of catalytic activity.

Key words: ZnO morphology, Benzene, Selective hydrogenation, Co-precipitation, Cyclohexene