Enhancing the catalytic performance of H-ITQ-13 zeolite in the conversion of methanol to olefins through regulating the aluminum distribution in its framework

Herein, K + was added in the synthesis gel to regulate the distribution of acid sites in the ITQ-13 zeolite and enhance its catalytic performance in the conversion of methanol to olefins (MTO). The results indicate that a proper content of K + ions in the synthesis gel can not only expedite the crystallization of ITQ-13 zeolite, but also significantly decrease the proportion of paired Al and distribute more Al atoms in the 10-ring sinusoidal channel out from the intersection cavity. Accordingly, over the H-ITQ-13(0.3 K) zeolite prepared using the synthesis gel with a KCl/Al 2 O 3 molar ratio of 0.3, the alkene cycle of MTO keeping to the dual cycle hydrocarbon pool (HCP) mechanism is preferably enhanced, whereas the hydride transfer and aromatization reactions are substantially suppressed. As a result, H-ITQ-13(0.3 K) exhibits much longer catalytic lifetime and higher selectivity to propene and butene , in comparison with the H-ITQ-13 counterpart obtained without adding K + .