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Abstract:
Co-reaction of methanol and ethylene (CME) have been performed on a number of proton type MFI zeolites and CHA zeotype materials to investigate the influence of zeolite topology and acidities upon the transformation of reactants and the formation of desired product of propylene. Two other reactions of methanol-to-olefins (MTO) and ethylene transformation (ET, with only ethylene as the reactant) were carried out in order to compare the promotion effect for the propylene productivity. The reactions were carried out at 773 K. The addition of methanol remarkably promoted the ethylene transformation over Al-poor HMFI zeolite and, more importantly, the by-products due to hydrogen-transfer reactions were
efficiently inhibited, leading to higher propylene selectivity. Such promotion effect was, however, not significantly observed upon the Al-rich HMFI zeolite. Moreover, such promotion effect of methanol upon
ethylene transformation was un-pronounced or non-existed upon the CHA zeotype materials including aluminosilicate, gallosilicate and silicoaluminophosphate, possibly owing to the CHA topology.
