Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (05): 1073-1079.doi: 10.3866/PKU.WHXB201303082

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effect of Water on Biphenyl Methylation over Modified HZSM-5

NA Yin-Na1, LIU Min1, SONG Chun-Shan1,2, GUO Xin-Wen1   

  1. 1 State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, Liaoning Province, P. R. China;
    2 EMS Energy Institute, Department of Energy and Mineral Engineering, Pennsylvania State University, University Park, PA 16802, USA
  • Received:2012-12-25 Revised:2013-03-06 Published:2013-04-24
  • Supported by:

    The project was supported by the Program for New Century Excellent Talent in University, China (NCET-04-0268) and Plan 111 Project of the Ministry of Education of China.

Abstract:

Nanosized HZSM-5 (n(SiO2)/n(Al2O3)=26) samples were hydrothermally treated with and without subsequent HNO3 leaching. The performance of the samples for the alkylation of biphenyl (BP) with methanol to 4-methylbiphenyl (4-MBP) under fixed-bed down-flow conditions was investigated. Characterization was conducted by the adsorption of pyridine using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric (TG) analysis. The effect of water on the catalytic performance of modified HZSM-5 was investigated. Both hydrothermal and combined hydrothermal-HNO3 treatments improved catalytic stability, with the latter exhibiting better stability. Without the addition of water, BP conversion behavior resembled an open down parabolic vs reaction time over modified HZSM-5. However, this change disappeared upon the addition of water to the reaction system. Both catalytic stability and selectivity of 4-MBP were improved upon the addition of water. BP conversion after 30 h on stream was 8.6%, and the selectivity of 4-MBP was as high as about 60%. Elevating the reaction temperature to 500℃ in the presence of water led to increased BP conversion with time on stream up to 30 h, and the selectivity was stable at ~58%. The activity and stability of HZSM-5 were improved, and para selectivity was enhanced with the addition of water.

Key words: Nano HZSM-5, Biphenyl, 4-Methybiphenyl, Hydrothermal treatment, Water

MSC2000: 

  • O643