What is Ester?
Ester is a chemical compound that is derived from an organic or inorganic acid in which at least hydroxyl (-OH) group is replaced by an alkyl (-O-) group.
Usually, esters are derived from a carboxylic acid and an alcohol. Esters with low molecular weight are commonly used as fragrances and found in essential oils and pheromones. Esters may also be obtained by reaction of acid halides or acid anhydrides with alcohols or by reaction of salts of carboxylic acids with alkyl halides.
What is Esterification?
Carboxylic acid esters formula RCOOR’ (where, R and R’ are any organic combining groups), that are commonly prepared by reaction of carboxylic acids and alcohols in the presence of hydrochloric acid or sulfuric acid and this process is called esterification.
In simple words, Esterification is a general name for a chemical reaction, in which two reactants (alcohol and an acid) form an ester as the reaction product.
The most commonly discussed ester is ethyl ethanoate. The hydrogen in the -COOH group has been replaced by an ethyl group. The formula for ethyl ethanoate is:
The ester is named in 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.
Structure of Ester
Esters feature a carbon-to-oxygen double bond that is also singly bonded to a second oxygen atom, which is then joined to an alkyl or an aryl group. Esters come in all shapes and sizes. They can be as small as allyl hexanoate for instance, pineapple odor and as large as a long-chain triglyceride, such as soybean oil.
Uses of Esters?
An ester is a sweet smelling substance. Some esters are used as food flavourings and other esters are used as fragrances or perfumes. Apart from that, esters can be made into polymers called polyesters. Polyesters can be used to make plastic bottles or polyesters can be made into fibres to make clothing.
Here are some of the other users of esters:
- Esters that are have fragrant odours are used as a constituent of perfumes, essential oils, food flavourings, cosmetics, etc
- Esters are used as an organic solvent
- Natural esters are found in pheromones.
- Naturally occurring fats and oils are fatty acid esters of glycerol.
- Phospoesters form the backbone of DNA molecules.
- Nitrate esters, such as nitroglycerin, are known for their explosive properties.
- Polyesters are used to make plastics.
- Esters are used to make surfactants E.g. soap, detergents.
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