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Conversion of ethane on modified zsm‐5 zeolites: A study of aromatization as a function of reaction media
Author(s) -
Hagen Anke,
Roessner Frank,
Reschetilowski Wladimir
Publication year - 1995
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270180608
Subject(s) - dehydrogenation , aromatization , chemistry , isomerization , catalysis , zsm 5 , photochemistry , hydrogen , zeolite , inorganic chemistry , organic chemistry
Ethane was converted into aromatic hydrocarbons on H‐ZSM‐5 and Zn‐ZSM‐5 at 773 K in a flow reactor system using nitrogen and hydrogen as carrier gases. Residence time was varied by changing catalyst weights to obtain information about primary and secondary reaction steps. On H‐ZSM‐5 ethane conversion proceeds via formation of ethene and subsequent oligomerization. Oligomers undergo fast isomerization, cracking and cyclization leading to a broad spectrum of aromatics. Methane is a secondary product. Dehydrogenation reactions proceed irreversibly. Introduction of zinc species significantly enhances the aromatization activity of H‐ZSM‐5 on the one hand and causes a change of reaction mechanism on the other. Oligomerization of olefinic intermediates can take place at zinc sites. In nitrogen, aromatization of C 6 olefins is faster than isomerization and cracking of these oligomers. Dehydrogenation steps proceed reversibly. On using hydrogen as the carrier gas over Zn‐ZSM‐5, the conversion of ethane as well as the formation of aromatics decrease. Furthermore, aromatics richer in hydrogen (especially C 8 aromatics) are then formed preferentially.