Active metal supported mesoporous materials as solid catalysts for the transesterification of triglycerides

Abstract

Expenditure of energy is indispensable for the survival of mankind and the chief share of demand has been laid upon non renewable resources like fossil fuels. In this context, biodiesel has emerged as an eco-friendly green fuel substitute for the typical diesel fuel. Biodiesel is basically mono alkyl esters of fatty acids synthesised via transesterification of triglycerides in the attendance of either solid/ heterogeneous, homogeneous or enzyme catalysts. Customary and typical homogeneous basic catalysts (NaOH and KOH) are exceedingly effectual for mercantile scale biodiesel production. However, this process defers the products which are contaminated with catalyst simultaneously generating enormous quantity of waste matter during washing and refinement processes. Furthermore, homogeneous alkali catalyst owing to their kindliness for moisture and free fatty acids (FFA) cannot be employed for transesterification of waste oils and necessitate FFA and moisture liberated expensive refined oil. With a view to outwit the issues associated with uniphasic catalysts, development and expansion of mesoporous solid reusable and stable catalysts has attracted momentous interest in recent years. In present thesis, mesoporous silica based catalysts, Li+ and Ce4+ impregnated mesoporous silica, 10-Na/ZnO/SBA-15, 20-Na-K/SBA-15 and 30-Na/ZrO2/SBA-15 were prepared as well as characterised by different analytical techniques such as powder XRD, BET surface area, FE-SEM, XPS, HRTEM, and Hammett indicator studies. These catalysts were triumphantly utilised for the biodiesel production from waste cottonseed oil, virgin cottonseed oil. Li+ and Ce4+ imbued SBA-15 has been prepared under normal atmospheric condition without using harsh hydrothermal method and trailing wet incipient route. The catalyst needed 4 h to give in the complete transesterification of waste cottonseed oil (gt 98% FAMEs yield) with moderate requirements of alcohol and catalyst amount at 65 °C.