Transesterificação

Transesterificação is a chemical reaction in which an ester is converted into another ester through reaction with an alcohol. The reaction involves the exchange of the alkoxy group (the part derived from the alcohol) of an ester with that of another alcohol. It is a type of ester synthesis. Typically, the reaction is catalyzed by either an acid or a base. In the presence of an acid catalyst, the reaction is reversible and can be driven towards product formation by removing one of the reactants or products. Base-catalyzed transesterification is generally faster and irreversible.

A common application of transesterificação is in the production of biodiesel. In this process, triglycerides (fats and oils) are reacted with methanol or ethanol in the presence of a catalyst to produce fatty acid methyl or ethyl esters and glycerol. Biodiesel is a renewable fuel. Another example is the synthesis of plasticizers, which are added to polymers to increase their flexibility. The reaction can also be used to modify the properties of existing esters, such as changing their solubility or boiling point. The mechanism generally involves nucleophilic attack of the alcohol on the carbonyl carbon of the ester.