Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (11): 3017-3022.doi: 10.3866/PKU.WHXB20101118

• CATALYSIS AND SURFACE STRUCTURE • Previous Articles     Next Articles

Carbon Deposition on a Toluene Disproportionation and Transalkylation Catalyst

MENG Gen, KONG De-Jin, QI Xiao-Lan, XU Zhong-Qiang   

  1. Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai 201208, P. R. China
  • Received:2010-04-22 Revised:2010-07-07 Published:2010-10-29
  • Contact: KONG De-Jin E-mail:kongdj.sshy@sinopec.com
  • Supported by:

    The project was supported by the Scientific and Technological Project of Shanghai Science and Technology Commission, China (08521101900).

Abstract:

The nature of carbon deposition on a toluene disproportionation and transalkylation catalyst was characterized using thermogravimetry and differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, N2 adsorption/desorption and NH3-temperature programmed desorption (NH3-TPD). Result showed that the kinetics of hard coke combustion approximately fitted a first order reaction with respect to the amount of coke and, therefore, most of the coke existed in a monolayer state and the corresponding apparent activation energy was about 110 kJ·mol-1. There were three kinds of carbon species on the surface of the Cat-1000 catalyst, which presented the catalyst after 1000 h reaction. The C atom fractions in the presence of C—O, C=O, and —C—C— were 22.7%, 9.1%, 68.1%, respectively. The formed carbon species on the Cat-1000 catalyst surface was mostly a graphite structure. The results showed that three quarters of the total carbon deposition on Cat-1000 was hard coke and the rest was soft coke. The specific surface area of the Cat-1000 catalyst decreased obviously compared with the catalyst without reaction (Cat-0). The Cat-1000 had almost unchanged acid intensity as well as high activity and stability. This shows that the cokes mainly deposit on the binder.

 

Key words: Toluene disproportionation, Transalkylation, Carbon deposition, Catalyst, Thermogravimetry and differential thermal analysis

MSC2000: 

  • O643.36