Influence of Zn²⁺ ions in a ZSM-5 catalyst on the C<inf>3</inf>-C<inf>4</inf> hydrocarbons aromatization process

Abstract

Catalysts, based on zeolite ZSM-5 modified by Zn2+ ions, are suitable for aromatization of C3-C4 hydrocarbons. Zn2+ ions change the acidity of the catalysts by blocking the strong Brönsted acid centers. The most probable aromatization mechanism is presented. The catalyst, based on a zeolite ZSM-5, with a module 50 and with a Zn content of 2.4%, was laboratory produced and applied to the aromatisation of a propane-butane mixture. In the temperature interval of 673-873 K propane was not converted, so it was supposed that the catalyst has Brönstcd acid centers of medium strength, as well as Lewis acid centers, since the concentration of Zn2+ ions, concerning the zeolite module, was rather high.