Emergence of Base Catalysts for Synthesis of Biodiesel

Abstract

Biodiesel is emerging as one of the prominent renewable sources of energy and is being envisaged as the fuel of the future. The synthesis of biodiesel needs a catalyst which may be either homogeneous or heterogeneous. The present chapter deals with the role of heterogeneous base catalysts as an alternative to homogeneous catalysts for the synthesis of biodiesel. The mode of preparation of heterogeneous catalysts is discussed in this chapter. The impregnation method has been found to be the commonly employed technique to support a compound on another compound to enhance the overall catalytic activity. The heterogeneous group of catalysts involved in the production of biodiesel in recent years includes oxides of calcium and magnesium, hydrotalcite, zeolites, and alumina loaded compounds. The catalytic activity, which is governed by the catalyst's basicity, pore size, and surface area has been critically discussed. The role of various catalysts in the transesterification reaction has been discussed. The optimized reaction conditions viz. alcohol to oil molar ratio, amount of catalyst, temperature, and reaction time for individual catalyst taking part in the reactionhas been reported. The leaching of the heterogeneous catalysts has been studied and it has been observed that only a few are resistant to leaching. The reuse of the catalysts after some pretreatment has also been discussed. © 2012 Scrivener Publishing LLC. All rights reserved.