What is the Difference Between Tautomerism and Metamerism?

The main difference between tautomerism and metamerism lies in the nature of the isomers involved and the factors that cause their existence. Here is a summary of their differences:

Tautomerism:

• Occurs when a single chemical compound exhibits dynamic equilibrium between two or more isomeric forms with the same molecular formula.
• The isomerization process is called tautomerization.
• Isomers differ from each other according to the position of protons.
• Common examples include keto-enol tautomerism, where a carbonyl compound containing at least one α-hydrogen atom is converted to an enol.

Metamerism:

• A type of structural isomerism where isomers have the same molecular formula but different alkyl groups attached to the same functional group.
• The isomerization process is called metamerization.
• Isomers differ from each other according to the alkyl groups attached to the functional group.
• Common examples include diethyl ether and methyl propyl ethers, which both contain the ether functional group but have different alkyl groups attached to the oxygen atom.

In summary, tautomerism involves isomers that differ in the position of protons and often occurs in keto-enol forms, while metamerism involves isomers that differ in the nature of alkyl groups attached to the same functional group.

Comparative Table: Tautomerism vs Metamerism

Tautomerism and metamerism are different types of structural isomerism. Here is a table comparing the two:

In tautomerism, isomers differ from each other according to the position of protons, whereas in metamerism, isomers differ from each other due to the different alkyl groups attached to the functional group in the molecule.