Acta Phys. -Chim. Sin. ›› 1995, Vol. 11 ›› Issue (08): 724-729.doi: 10.3866/PKU.WHXB19950811

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The Study of Propane Aromatization over ZnHZSM-5:Activation of Propane

Cheng Mo-Jie,Wang Jiang-Mai,Yang Ya-Shu,Li Can   

  1. State Key Laboratory of Catalysis,Dalian Institute of Chemical Physics,Academic Sinica,Dalian 116023
  • Received:1994-06-11 Revised:1995-04-03 Published:1995-08-15
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Abstract:

The IR spectra of hydroxyl and probe molecule CO and the aromatization of propane were investigated over HZSM-5, ZnHZSM-5 and ZnNaHZSM-5.The IR spectra showed that the relative band intensity of strong acidic hydroxyl groups at 3610cm-1 decreased by Zn2+ ion exchange and sodium hydroxide impregnatin, which indicated that Zn2+ and Na+ cations had occupied the cation centers in the zeolite. The band appearing at 2232cm-1 in CO IR spectra demonstrated that Zn2+ cations were a sort of strong lewis acid. The greatly improvement of propane conversion and aromatics selectivity after Zn2+ incorporation into HZSM-5, the decreasing of propane conversion and the increasing of propane selectivity and yield from sodium hydroxide impregnation depicted that zinc species directly participate in propane dehydrogenation. In conclusion, zinc lewis acid sites are the activation centers for propane dehydrogenation, on which propane could be hetero-cracking activated and directly dehydrogenated.

Key words: ZnHZSM-5, Propane;Aromatization, Dehydrogenation, Activation