Ketones are the compounds which contain carbonyl group. The structure of ketone is:
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:
- 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’.
- 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|
|Dimethyl Ketone or Acetone||Propanone|
|Ethyl methyl ketone||Butan-2-one|
|Methyl Propyl Ketone||Pentan-2-one|
Acetone or propanone is the simplest ketone. Its molecular formula is CH3 – CO – CH3 and its structural formula is
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.
- Acetone can be prepared by oxidation of isopropyl alcohol in the presence of oxidizing agent K2Cr2O7 and sulphuric acid.
2. By Distillation of Calcium Salts of Acids
Acetone can be prepared by distilling the calcium salts of acids. For example,
Properties of Acetone
Following are the physical properties of acetone:
- Acetone is a colourless, volatile and highly inflammable liquid.
- Its boiling point is 329 K.
- It is miscible with water, alcohol and ether.
- It has a pleasant smell.
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.
2. Reduction Reaction
Acetone gives 2-Propanol (isopropyl alcohol) on catalytic hydrogenation in the presence of catalysts such as sodium borohydride (NaBH4).
3. Reaction with Hydrogen Cyanide (HCN)
Acetone reacts with hydrogen to form propane cyanohydrin.
Uses of Acetone
- It is very important solvent and is used in industries as a solvent.
- It is used as nail polish remover.
- It is used in preparation of chloroform and iodoform.
- It is used in manufacture of plastics.