Catalysis in Biodiesel Production by Transesterification Processes-An Insight

P M Ejikeme,N P Nwafor,J A Ibemesi,C A C Egbuonu,C L Ejikeme,I D Anyaogu,K Ukogu

doi:10.1155/2010/689051

Abstract

Biodiesel is the mono-alkyl esters of long chain fatty acids derived from renewable lipid feedstock, such as vegetable oils and animal fats, for use in compression ignition (diesel) engines. The conversion of component triglycerides in oils to simple alkyl esters with short chain alcohols like methanol and ethanol amongst others is achieved mainly by transesterification. The transesterification reaction, a reversible process proceeds appreciably by the addition of catalysts, which can be acidic, basic or organic in nature, usually in molar excess of alcohol. The economy of the process depends on the type and quantity of catalyst used among other factors. The catalyst can be homogeneous or heterogeneous depending on whether it is in the same or different phase with the reactants; oils and alcohols. This paper attempts to give an insight into some of the various types of catalysts that have been used to effect the transesterification of vegetable, waste and animal oils in biodiesel production.

Highlights

Chemical transesterification or alcoholysis of triglycerides or the esterification of free fatty acids using short-chain alcohols in the production of alkyl esters or biodiesel was first reported[1] on August 31st 1937 in a Belgian Patent by Chavanne of the University of Brussels[2]
Various homogeneous and heterogeneous catalysts, ranging from base, acid to enzyme[10,11] as well as carbon catalysts produced from sugar starch and cellulose have been developed for use in biodiesel production
The greater tolerance of an acid catalyst to the free fatty acids (FFAs) content compared to an alkaline catalyst was confirmed in a report by Canakci and Van Gerpen[65]

Summary

Introduction

Chemical transesterification or alcoholysis of triglycerides or the esterification of free fatty acids using short-chain alcohols in the production of alkyl esters or biodiesel was first reported[1] on August 31st 1937 in a Belgian Patent by Chavanne of the University of Brussels[2]. In the early 1940s researches that did not anticipate the production of alkyl esters as fuel were patented[3,4,5,6,7,8]. The original objective of the work was to develop a simplified method for extracting glycerol during soap production[9]. Various homogeneous and heterogeneous catalysts, ranging from base, acid to enzyme[10,11] as well as carbon catalysts produced from sugar starch and cellulose have been developed for use in biodiesel production

Objectives

Findings

Conclusion