Structure and naming of esters
R is H or an alkyl or aryl group
R' is either an alkyl or aryl group
Esters are referred to as carboxylic acid derivatives.
Reaction of a carboxylic acid (RCO2H) and an alcohol (R'OH) gives an ester and H2O.
Some esters that are used commerically are shown below. Esters may have a pleasant aroma, some of those shown and are responsible for the smell that we associate with common fruits. It should be pointed out, however, that compounds with a nice smell may not necessarily be esters.
3-methylbutyl pentanoate
a component of banana flavour
methyl ethanoate
used in nail polish remover, model paint
3-methylbutyl ethanoate
a component of apple flavour
Note that two of the esters shown are derived from the same acid (ethanoic - CH3COOH).
Another pair of these esters has the same five-carbon alcohol component. (3-methylbutan-1-ol).