The influence of si/al ratio on the physicochemical and catalytic properties of mgo/zsm-5 catalyst in transesterification reaction of rapeseed oil

Abstract

This work presents the comparative physicochemical and catalytic studies of metal oxide MgO catalysts in a transesterification reaction. The influence of the Si/Al ratio in the catalytic material on their catalytic properties in the studied process was extensively evaluated. In addition, the effect of the type of zeolite ZSM-5 form on the catalytic reactivity of MgO based catalysts was inves-tigated. In order to achieve the main goals of this work, a series of MgO/ZSM-5 catalysts were pre-pared via the impregnation method. Their physicochemical properties were studied using X-ray diffraction (XRD), BET, FTIR and TPD-CO2 methods. The highest activity in the studied process exhibited MgO catalyst supported on ZSM-5 characterized by the highest ratio between silica and alumina. The most active catalyst system in the transesterification reaction was 10% MgO/ZSM-5 (Si/Al = 280), which showed the highest value of higher fatty acid methyl esters (94.6%) and high yield of triglyceride conversion (92.9%). The high activity of this system is explained by the alkalin-ity, sorption properties in relation to methanol and its high specific surface area compared to the rest of the investigated MgO based catalysts.