Post Synthesis Architectural Pore Modification of Mobil Five (MFI) Zeolite for Enhancing its Catalytic Activity

Abstract

Dealumination and desilication of synthesized nanoporous MFI samples have been investigated in order to create and modify the acidity of the samples. Desilication of the synthesised samples carried out by treating the samples by an alkaline solution leads to an impressive nanoporosity development with increase in the acidic properties, while dealumination of the synthesised samples carried out by treating the samples by an acidic solution mainly modifies the acidity of the synthesised MFI zeolite. The present study shows that application of alkaline and acidic treatments results in modification of the MFI zeolites with independently tailored pore architecture and acidic properties. Such modification enhances the catalytic activity of the samples under different conditions. XRD as well as FT-IR studies have been carried out to characterize the formation of the parent as well as modified MFI zeolite. Specific surface area, pore diameter and pore volume of the samples were studied by N2 adsorption-desorption isotherm. BET specific surface area was found to increase with increase in Si/Al molar ratio. The thermal stability of the samples was studied using thermal gravimetric analysis. The synthesised samples were found to show weight loss in three different ranges. The shape and size of crystalline MFI samples were investigated with SEM analysis. The catalytic activity of synthesized parent and modified MFI zeolites were investigated by the acetalization reaction of cyclohexanone with methanol under different reaction conditions. The % conversions of the dealuminated samples were found to be greater than that of the desilicated catalyst.