What Is Transesterification?

Transesterification is an organic process in which the combination of an alcohol with an ester produces a different alcohol. The process may require the addition of a catalyst to facilitate the change. The catalysts used to create this transition may be either an acid or a base. In some cases, a bio-catalyst enzyme is used to start the process.

The chemical process by which transesterification takes place is fairly rudimentary. Esters of alcohol are made by combining an acid with a water-based alcohol and then distilling the mixture to remove the water. When an alcohol and an ester are combined with a catalyst, which can be acid, base, or enzymatic in nature, it starts a chemical reaction. The catalyst donates or harvests a proton depending upon whether it is acidic or basic. This change causes the organic group R" of the alcohol to switch places with the organic group R' of the ester. The result is a new ester and alcohol.

Transesterification is used for many different purposes. The esters created are often sweet smelling and are used to make incense and perfumes. The alcohol products can be used to provide fuel for equipment and for further chemical reactions. In some cases, the process is also used to create herbicides and other industrial strength chemicals.

One of the better known examples of this chemical process is in the creation of bio diesel. Bio diesel is a chemical compound made by the transesterification of vegetable oil. The triglycerides, or fat, in the oil are converted into useable fuel through the process. This form of transesterification has been used to create bio diesel to fuel large vehicles in some countries, even prior to World War II.

The transesterification of bio diesel is an enzymatic form of the process. The first patent on the process was issued to Colgate in the 1950s, but research was conducted on the technique long before this date. Much of the early research into the transesterification of bio diesel dates back to the 1940s, when the war efforts of the U.S. were focused on finding rapid ways to produce glycerine for explosives.

Research has also been conducted in the realm of bio lipid transesterification. Specialized methanol has been produced in a laboratory setting using bio lipids and this chemical process. Researchers have been able to use high temperatures and pressurization to induce the process in these bio lipid compounds.