The acid-base and catalytic properties of a series of Mordenite zeolites for the pyrolysis of n-hexane, and modified the least acidic Na type Mordenite by supporting basic metal (alkali, alkaline earth) and reductive transition metal oxides were studied. With the increase of zeolite acidity, the activity increased while both the selectivity of ethylene and the ratio of (C1 + C2)/C3 decreased. This was due to the cracking reaction on acidic catalysts. Secondary undersirable reaction, e.g., aromatization, might occur between the olefin product and the carbenium ion intermediates, and coke formation became severe with the increase of strong acidity. The metaloxides that is easier to reduce (except MnO) showed approximately higher catalytic activity and yields to alkenes including ethylene. In the presence of steam, the catalytic activity and ethylene selectivity decreased significantly.
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