Esters

Esters Esters are formed by the reaction of a carboxylic acid with an alcohol e.g. CH3COOH + CH3OH = CH3COOCH3 + H2O Ethanoic acid Methanol Methyl ethanoate

Naming esters: methyl ethanoate The first part of the ester name comes from the parent alcohol with the - anol changed to – yl and the second part of the name comes from the parent acid with the - oic acid changed to – oate.

Methyl methanoate HCOOCH3

Ethyl methanoate HCOOC2H5

Methyl ethanoate CH3COOCH3

Ethyl ethanoate CH3COOC2H5

Physical properties Physical state: Liquid Boiling points higher than the corresponding alkanes, but lower than the corresponding alcohols

Physical properties Soluble in water and non-polar solvents such as cyclohexane As the number of carbon atoms in a molecule of the ester increases, solubility in water decreases, while solubility in cyclohexane increases

Occurrence and uses of esters Occur naturally in fruits – are responsible for their flavours - and flowers – are responsible for their pleasant smells Fats and oils are naturally occurring esters of long chain carboxylic acids Ethyl ethanoate is used as a solvent for printing inks and paints