SPM Chemistry

Ester

Ester

  1. Esters are non-hydrocarbon organic compounds containing carbon, hydrogen and oxygen.
  2. It is formed when a carboxylic acid reacts with an alcohol.

General Formula:

CmH2m + 1COOCnH2n + 1

where
m = 0, 1, 2, 3
n = 1, 2, 3

Example

Ester Formula 
 Methyl methanoate
(m=0, n=1)
 HCOOCH3
 Ethyl methanoate
(m=1, n=1)
 CH3COOCH3
 Ethyl ethanoate
(m=1, n=2)
 CH3COOC2H5
 Propylethanoate
(m=2, n=2)
 C2H5COO C2H5

Functional group:

Formation:

  1. Esters are produced when carboxylic acid reacts with alcohol in the presence of concentrated sulphuric acid as a catalyst.
  2. This reaction is called the esterification reaction.
Physical Properties of Ester
  1. Ester has the following properties:
    1. having fragrant similar to fruits
    2. insoluble in water but soluble in organic solvent
    3. low boiling point
    4. less dense than water
    5. colourless liquid
    6. volatile
  2. Ester can be found naturally in plants.

Uses of Ester in Daily Life

  1.  As food flavourings
  2. as a fragrant in soap and detergent
  3. To make cosmetics (perfumes)
  4. To make medicine