Ultrasound-Assisted Modification of Zeolite Catalyst for Dimethyl Ether Conversion to Olefins with Magnesium Compounds

Beneficial use of ultrasound irradiation in synthesis of beta–clinoptilolite composite used in heavy oil upgrading process

“…According to the literature, strong Brønsted acidic sites are responsible of hydrogen transfer reactions and aromatic production. 54,61 With optimized amount of acidity, naphthenes and olens have the possibility to convert to aromatics and paraffins according to the general reaction: 43 Naphthenes + olefins / aromatics + paraffins This conversion could be attributed to the hydrogen transfer ability of the catalyst, which is a function of acidity and mesoporosity. Beta sample has produced highest amount of paraf-nic and aromatic hydrocarbons due to the high acidity and mesoporous structure, which facilitates diffusion through the micropores.…”

Alumina binder effects on the hydrothermal stability of shaped zeolite-based catalyst bodies

“…Several modifications in zeolite powder catalysts have been studied, as acidity and porosity have a key role in catalytic activity to achieve higher selectivity towards light olefins. Postsynthesis modification, such as metal incorporation (e.g., Mg and Ca), is, among others, a strategy to enhance the light olefins yields [21][22][23][24][25][26][27][28] . It has been proved that metal-modified zeolites exhibited higher selectivity towards ethylene and propylene, while the lifetime of the catalyst materials was improved.…”

“…Post-synthesis modification, such as metal incorporation (e.g., Mg and Ca), is, among others, a strategy to enhance light olefin yields. [21][22][23][24][25][26][27][28] It has been proved that metal-modified zeolites exhibited higher selectivity towards ethylene and propylene, while the lifetime of the catalyst materials was improved. Altering the Si/Al ratio and, consequently, the strength and the density of Brønsted acid sites (BASs) has been beneficial for the catalyst performance in the MTH process.…”