Esters

• Esters have the functional group COO somewhere in the middle of the molecule
• Esters have pleasant 'sweet or fruity' smells
• Esters are volatile, so they evaporate easily.
• Esters are often used in perfumes or food flavourings
• Esters are made using a carboxylic acid and alcohol. For example to make ethyl ethanoate you need ethanoic acid and ethanol + an acid catalyst (normally concentrated sulfuric acid). When combined ethanoic acid looses it's OH group and ethanol loses the H from it's OH group. This will create a water molecule (the byproduct).

  
• As well as calling the COO group an ester group, you can also call it an ester link, as it links the carboxylic acid and the alcohol.
• Ethanoic acid + ethanol  ➔  Ethyl ethanoate 

  (This is the only ester you need to know how to form)