Carbon Compounds


Ketones

Ketones are the compounds which contain carbonyl group. The structure of ketone is:

 

Ketones

 

Where R and R’ represents two alkyl groups which may be same or different. This functional group is also known as ketonic group. The general formula of ketone is CnH2n+1COCnH2n+1.

Nomenclature of Ketones

In IUPAC system of nomenclature following general rules are followed for naming ketones:

  1. The longest chain carrying the carbonyl group is selected and the name is derived by replacing the terminal ‘e’ of the name of corresponding alkanes by the suffix ‘one’.
  2. The parent chain is numbered in such a way that the keto group gets the lowest number. For example,

Molecular Formula Common Name IUPAC Name
Molecular Formula of Acetone Dimethyl Ketone or Acetone Propanone
Molecular Formula of Ethyl methyl ketone Ethyl methyl ketone Butan-2-one
Molecular Formula of Methyl Propyl Ketone Methyl Propyl Ketone Pentan-2-one

Acetone

Acetone or propanone is the simplest ketone. Its molecular formula is CH3 – CO – CH3 and its structural formula is Structure Of Ketone

Preparation of Acetone

Acetone can be prepared by following methods:

1. From 2-Propanol

Acetone can be prepared by dehydrogenation of 2-Pronpanol in the presence of heated copper at a temperature of 573 K.

 

Formation Of Acetone From 2-Propanol

 

Acetone can be prepared by oxidation of isopropyl alcohol in the presence of oxidizing agent K2Cr2O7 and sulphuric acid.

 

Formation Of Acetone From Isopropyl Alcohol

 

 

2. By Distillation of Calcium Salts of Acids

Acetone can be prepared by distilling the calcium salts of acids. For example,

 

Formation Of Acetone From Calcium Acetate

 

Properties of Acetone

Physical Properties

Following are the physical properties of acetone:

  1. Acetone is a colourless, volatile and highly inflammable liquid.
  2. Its boiling point is 329 K.
  3. It is miscible with water, alcohol and ether.
  4. It has a pleasant smell.

Chemical Properties

       Following are the important chemical reactions of acetone:

1. Oxidation Reaction

Acetone can be oxidized by reacting with strong oxidizing agents like potassium dichromate and sulphuric acid to produce acetic acid, carbon dioxide and water as products.

 

Oxidation Of Acetone

 

2. Reduction Reaction

Acetone gives 2-Propanol (isopropyl alcohol) on catalytic hydrogenation in the presence of catalysts such as sodium borohydride (NaBH4).

 

Reduction Of Acetone

 

3. Reaction with Hydrogen Cyanide (HCN)

Acetone reacts with hydrogen to form propane cyanohydrin.

 

Reaction Of Acetone With Hydrogen Cyanide

 

Uses of Acetone

  1. It is very important solvent and is used in industries as a solvent.
  2. It is used as nail polish remover.
  3. It is used in preparation of chloroform and iodoform.
  4. It is used in manufacture of plastics.

Test your understanding and answer these questions:

  1. What are ketones? give examples.
  2. What is acetone? give its use.

Share your Feedback

6 + 5 =