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Ball and stick model of the methyl acetate molecule

Methyl ester of a carboxylic acid. The methyl ester residue is marked in blue. R stands for a hydrogen atom or an organic residue (alkyl residue, aryl residue, etc.).

Methylesters are chemical compounds that belong to the group of esters. They are formed by esterification of carboxylic acid with methanol and contain characteristic ester group.

Occurence

Methylesters are often called fruit esters, since they are component of many fruits characteristic aroma. Most notable one is methyl cinnamate, that is part of flavour of strawberries, basil and eucalyptus.

Manufacturing

One of ways to manifacture methyl esters is by condensation of carboxylic acid and methanol in presence of acidic catalyst.

Another way of preparation is reaction of carboxylic acid anhydrides and methanol. Methyl esters can also be produced by algae via transesterification of lipids.

Uses

There are two main uses for methyl esters:

Flavouring agents

• Methyl butyrate - smell is reminiscent of apples and pineapples
• Methyl phenylacetate - is part of aroma of honey, brandy, peppers, and some wines
• Methyl benzoate - smell is reminiscent of the fruit of the feijoa tree

Diesel subsitute in biodiesel or as an additive to diesel fuel. As a main resource for production of methylesters for fuel consumption are vegetable oil, animal fat, algae oil, and vegetable oil waste.