What are Esters???

Definition of Esters and Esterification:

Ester is an organic compound formed when an alcohol reacts with a carboxylic acid.

Esters are produced during the Esterification Process.

Esterification Process - Alcohols and carboxylic acids react in the presence of concentrated sulphuric acid to form esters. (Sulphuric acid acts a catalyst to produce esters)

Acid + Alcohol = Ester + Water( this reaction is esterification)
E.g:Ethanoic acid + Ethanol = Ethyl Ethanoate + Water
CH3COOH(l) + C2H5OH(l) = CH3COOC2H5(l) + H2O(l)

Ester Preparation( in small quantities) :
E.g: Butyl Ethanoate

1. Mix Butanol ( the alcohol), Ethanoic acid (carboxylic acid) and Sulphuric acid and heat it in a waterbath.
   
2. When poured into a beaker of water, the ester forms a colourless layer on top of the water.

How to identify Esters?

As the background of our blog suggests, esters are sweet- smelling substances just like roses and any other flowers..

Characteristics of Esters:

• Sweet- smelling
• Colourless liquids
• Insoluble in water
• Good Solvents for other compounds
• have low boiling points

Esters can be divided into 2 categories: 1) Natural
2) Synthetic

Natural Esters: Fruits contain natural esters.Strong , sweet smell from bananas, pineapples, other fruits due to presence of esters. Each ester owns characteristic smell.
E.g:

1) Ethyl Methanoate => H-CO₂-CH₂-CH_{3 => Rum
2)} Methyl Phenyl Ethanoate => C₆H₅-CH₂-CO₂-CH_{3 =>} Honey
3) Benzyl Ethanoate => C₆H₅-CH₂-CO₂CH_{3 =>} Jasmine
4) Pentyl Ethanoate => CH₃-CO₂-CH₂-CH₂-CH₂-CH₂-CH_{3 =>} Pear
5) 3-Methylbutyl Ethanoate => CH₃-CO₂-CH₂-CH₂-CH(CH₃)-CH_{3 =>} Banana
6) Octyl Ethanoate=> CH₃-CO₂-CH₂(CH₂)₆-CH_{3 =>} Orange
7) Methyl Butanoate=> CH₃-CH₂-CH₂-CO₂-CH_{3 =>} Pineapple
8) Ethyl Butanoate => CH₃-CH₂-CH₂-CO₂CH₂CH_{3 =>} Peach
9) 3-Methylbutyl-3-Methylbutanoate => CH₃CH(CH₃)CH₂CO₂CH₂CH₂CH(CH₃)CH₃=>Apple
10) Pentyl Butanoate=> CH₃-CH₂-CH₂CO₂-CH₂-(CH₂)₃-CH_{3 =>} Apricot

Synthetic Esters: Artificial fruit flavours in foods. Fruity flavours for foods and drinks such as milkshakes, ice-cream, chewing gum, jellies, sweets and cakes.



Other uses of Esters: Used as solvents for glues, perfumes, nail polish remover and paints.


Naming Esters : ' -yl' represents alcohol
'- oate' represents acid

E.g: Methyl Ethanoate- Methanol and Ethanoic acid

Butanoic acid + Ethanol => Ethyl Butanoate (artificial pineapple flavouring) + Water

Ester search at Cold Storage...

Today, Our group went to the Cold Storage at Causeway Point to search for Esters. Here are the names of the esters which found:

1) Ethyl Acetate (Found in Nail Polish)
2) Tocopheryl acetate (Found in Skin Cream)
3) Octyl methoxycinnamate
4) Benzoyl peroxide
5) Sodium Phenylbenzimida
6) Propyl Myriatate

Making of ester

Making Of Ester