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ESTERS
This name is given to those generally pleasant smelling substances that contain the ester functional group
The sweet and pleasant odours and tastes of many foods are due to complex mixtures of organic compounds, of which esters are generally the most prevalent component.
Esters are derived from carboxylic acids. A carboxylic acid contains the -COOH group, and in an ester the hydrogen in this group is replaced by a hydrocarbon group of some kind. This could be an alkyl group like methyl or ethyl, or one containing a benzene ring like phenyl. A common ester – ethyl ethanoate
The most commonly discussed ester is ethyl ethanoate. In this case, the hydrogen in the -COOH group has been replaced by an ethyl group.
Notice that the ester is named the opposite way around from the way the formula is written. The “ethanoate” bit comes from ethanoic acid. The “ethyl” bit comes from the ethyl group on the end.
Notice that the acid is named by counting up the total number of carbon atoms in the chain – including the one in the -COOH group. So, for example, CH3CH2COOH is propanoic acid, and CH3CH2COO is the propanoate group.