Fettsyraalkylester

Fettsyraalkylester, or fatty acid alkyl ester, is a class of esters formed from long-chain fatty acids and alcohols. The typical members are fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAEE), where the fatty acyl group comes from a fatty acid and the alkyl group comes from methanol or ethanol. The general structure is R-CO-OR', with R representing the fatty acid chain and R' the alkyl group derived from the alcohol.

Production of fatty acid alkyl esters is usually achieved by transesterification of fats and oils (triglycerides) with methanol or ethanol in the presence of a catalyst (base or acid). This reaction yields fatty acid esters and glycerol as a byproduct. Direct esterification of free fatty acids with alcohols is another route, though less common for large-scale biodiesel production. FAAEs can also be obtained from renewable feedstocks such as vegetable oils and animal fats, making them a prominent class of bio-based esters.

The primary use of fatty acid alkyl esters is as biodiesel components. FAME dominates due to methanol’s low cost and established processing routes, while FAEE offers alternatives in fuel formulations. Beyond fuels, these esters serve as lubricants and lubricity additives, plasticizers, solvents, and intermediates in chemical syntheses. Their properties depend on the fatty acid chain length and degree of unsaturation, with factors such as cetane number, cold-flow behavior, and oxidative stability guiding application.

Safety and environmental considerations include biodegradability and renewable sourcing, which can reduce lifecycle greenhouse gas emissions compared with fossil diesel. However, handling methanol-containing products requires adherence to safety guidelines due to methanol toxicity.