Chinese Journal of Catalysis ›› 2017, Vol. 38 ›› Issue (3): 509-517.DOI: 10.1016/S1872-2067(17)62755-4

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Zinc-modified Pt/SAPO-11 for improving the isomerization selectivity to dibranched alkanes

Zhichao Yang, Yunqi Liu, Jinchong Zhao, Jianxia Gou, Kaian Sun, Chenguang Liu   

  1. State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corp. (CNPC), China University of Petroleum (East China), Qingdao 266580, Shandong, China
  • Received:2016-10-26 Revised:2016-11-21 Online:2017-03-18 Published:2017-03-22
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21676300).

Abstract:

Zinc-modified Pt/SAPO-11 catalysts were prepared by incipient wetness impregnation and assessed in the hydroisomerization of n-octane. Their physicochemical properties were investigated using powder X-ray diffraction, scanning electron microscopy, nitrogen adsorption-desorption, pyridine-adsorbed infrared spectroscopy, temperature-programmed desorption of NH3, temperature-programmed reduction of hydrogen, temperature-programmed desorption of hydrogen, transmission electron microscopy, and X-ray photoelectron spectroscopy. The addition of zinc resulted in high dispersion of platinum. Zinc acted as a competitive adsorbent, changed the location of platinum. The catalyst with a zinc loading of 0.5% gave the highest selectivity to dimethylhexanes, but the conversion was lower than those achieved with the other catalysts. Dimethylhexanes have large molecular diameters, and therefore their diffusion may be difficult. This weakens the catalytic activity of the zinc-modified catalysts and lowers the n-octane conversion.

Key words: Pt/SAPO-11 catalyst, Zinc, n-Octane , Hydroisomerization, Dibranched alkanes