Uses of Esters (or the wooly bit)
Esters are often utilised in the production of perfumes and food flavourings due to their distinctive sweet tastes and smells, as well as their volatility.
Much more important than their uses in perfumes however is esters increasing use within biodiesel. Triglyceride esters - extracted from plants such as oilseed rape - are a renewable form of fuel which is currently being used to supplement existing fuels obtained from crude oil and other fossil fuels, and may entirely supplant these conventional fuel sources.
Heating the plant oils with a strong alkali hydrolyses the triglyceride esters into glycerol and the fatty acids. Esterification of the fatty acids with methanol forms methyl esters used in biodiesel. These natural acids are ideal fuels sources as the carbon chains are typically long, unbranched chains. This means that they have a large surface area and are therfore highly reactive. This means they combust easily, making them useful fuels.
Biodiesel has the advantage of being carbon neutral - the carbon dioxide released when the fuel is burnt is offset by the CO2 absorbed when the plants are grown. However, this arguement for using biodiesel is flawed, as no account is made of carbon dioxide released from the use of conventional oil-based fuels which are used for the harvesting and processing the plants. None-the-less, renewability is a major advantage for the biodiesel over crude oil based fuels.
Unfortunately, the use of land to grow crops for production of biodiesel results instead of food stuffs mean that food production falls, food prices increasing and less developed countries lose the ability to feed their populations effectively. Mass starvation is an eminant possiblity as more land is dedicated to the production of such fuels.