ABSTRACT
The concept of using vegetable oil as a fuel dates back to 1895 when Dr. Rudolf Diesel developed the first diesel engine to run on vegetable oil. Diesel demonstrated his engine at the World Exhibition in Paris in 1900 using peanut oil as fuel [1]. Biodiesel is the name for alkyl esters of fatty acids made from vegetable oils or animal fats via transesterification. Biodiesel is renewable fuel and exhibits advantages over petroleum derived diesel fuel in terms of emissions and it does not require any modification of the existing diesel engines. It does not contain sulfur and aromatic molecules and the level of toxic emissions is lower compared to that of diesel fuel [2]. The most traditional methodology for the preparation of biodiesel from vegetable oils is transesterification with methanol (Fig. 12.1). Transesterification was conducted as early as in 1853. One of the first uses of biodiesel (transesterified vegetable oil) was powering heavy vehicles in South Africa before World War II. Transesterification is the reaction of oil with an alcohol to form biodiesel and a by-product, glycerol. It is in principle the action of one alcohol displacing another from an ester. As the reaction is reversible, an excess of alcohol is usually used to force the equilibrium to the product side. The stoichiometry for the reaction is 3:1 alcohol to oil; however in practice this is usually increased to 6:1 or more to increase product yield.
