Making an EsterEsters are made by reacting a carboxylic acid with an alcohol in the presence of concentrated sulphuric acid which acts as a catalyst.

Ethanoic Acid + Ethanol

OH H

Ethyl ethanoate + Water

O-C-C-HH

H

H

H

H-C-CH

H O

CH3COOC2H5 H2O

Depending on the alcohol and acid used, many different fragrances can be made.

ALCOHOL ACID ESTER FRAGRANCE

1-pentanol butanoic acid apricot

1-pentanol salicylic acid pineapple

1-pentanol ethanoic acid banana

Ethanol butanoic acid apple

ethanol ethanoic acid fruity

Most esters have a pleasant odour.

WARNING!! The alarm pheromone of bees makes them attack would be invaders. The pheromone is the ester 3-methylbut-1-ylethanoate, which also happens to be the principal component of banana oil.

Don't eat bananas near a beehive!