Transesterification in the context of Catalyst

Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats.

The roots of biodiesel as a fuel source can be traced back to when J. Patrick and E. Duffy first conducted transesterification of vegetable oil in 1853, predating Rudolf Diesel's development of the diesel engine. Diesel's engine, initially designed for mineral oil, successfully ran on peanut oil at the 1900 Paris Exposition. This landmark event highlighted the potential of vegetable oils as an alternative fuel source. The interest in using vegetable oils as fuels resurfaced periodically, particularly during resource-constrained periods such as World War II. However, challenges such as high viscosity and resultant engine deposits were significant hurdles. The modern form of biodiesel emerged in the 1930s, when a method was found for transforming vegetable oils for fuel use, laying the groundwork for contemporary biodiesel production.

Fatty acid methyl esters (FAME) are a type of fatty acid ester that are derived by transesterification of fats with methanol. The molecules in biodiesel are primarily FAME, usually obtained from vegetable oils by transesterification. They are used to produce detergents and biodiesel. FAME are typically produced by an alkali-catalyzed reaction between fats and methanol in the presence of base such as sodium hydroxide, sodium methoxide or potassium hydroxide. One reason for using FAME (fatty acid methyl esters) in biodiesel production, rather than free fatty acids, is to mitigate the potential corrosion they can cause to metals of engines, production facilities, and related infrastructure. While free fatty acids are only mildly acidic, over time they can lead to cumulative corrosion. In contrast, their esters, such as FAME, are less corrosive and therefore preferred for biodiesel production. As an improved quality, FAMEs also usually have about 12-15 units higher cetane number than their unesterified counterparts.