Modified zeolite ZSM-5 for the methanol to aromatics reaction

 ZSM-5 - Zeolite Socony Mobil – 5, (structure type MFI – mordenite framework inverted) is an aluminosilicate zeolite mineral belonging to the pentasil family of zeolites. Its chemical formula is Na_nAl_nSi_96–nO₁₉₂·16H₂O (0<n<27). Patented by Mobil Oil Company in 1975, it is widely used in the petroleum industry as a heterogeneous catalyst for hydrocarbon isomerization reactions.



Catalysts comprising zeolite ZSM-5 impregnated with precious metals including Ag, Cu, Ni, Pd, Ir and Ru, have been tested for the methanol to hydrocarbons reaction in a continuous flow fixed bed reactor. Comparison with the activity of unmodified ZSM-5 showed that Ag, Cu and Ni enhanced the selectivity to C₆–C₁₁ aromatic products by a factor of two or higher. Moreover, Ag/ZSM-5 showed improved selectivity for the C₆–C₇ fraction of aromatic products. Ni/ZSM-5 was found to be selective to naphthalene, while Cu/ZSM-5 was selective for C₉–C₁₁ aromatic products.

It was ascertained that all the impregnated metals were present as metal oxides in the starting materials. It is therefore proposed that the enhanced selectivity to aromatic products is due to the interaction of the acid sites of the zeolite with the basic sites of the metal oxide at the edge of the zeolite crystals, as well as the possible coordination of propene molecules formed during the reaction, that are likely to be the building blocks for the formation of aromatics.

Zeolites for Selective catalytic reduction (SCR) of NO_x
Zeolites are versatile, microporous materials that can be tailored for many different applications. They exhibit a large number of different crystal orientations, shapes and sizes and can be further modified with a variety of promoters. In our research we aim to explore design strategies, develop structure-reactivity relations and propose design principles to achieve desired catalytic properties. In close collaboration with Dr. Rimer and Dr. Harold, zeolite materials are synthesized, characterized and tested under realistic conditions for their activity as NO_x reduction _.