The key difference between intramolecular redox and disproportionate redox reaction is that intramolecular redox reactions occur when a single molecule undergoes oxidation and reduction in the same chemical element or different chemical elements whereas disproportionate redox reactions involve the oxidation and reduction of the same chemical element in a single substrate.
Intramolecular redox reactions and disproportionate redox reactions are two types of inorganic chemical reactions where oxidation and reduction reactions occur parallel to each other. Both these chemical reactions involve the oxidation and reduction half-reactions occurring in the same chemical compound/ in a single substrate molecule. The two types differ from each other according to the chemical element in which these half-reactions take place.
CONTENTS
1. Overview and Key Difference
2. What are Intramolecular Redox Reactions
3. What are Disproportionate Redox Reactions
4. Side by Side Comparison – Intramolecular Redox vs Disproportionate Redox Reaction in Tabular Form
5. Summary
What are Intramolecular Redox Reactions?
Intramolecular redox reactions are chemical reactions that involve a single substrate where oxidation and reduction occur in the same chemical element or in two different chemical elements. In other words, in some intramolecular redox reactions, the oxidation and reduction occur in the same chemical element while in other intramolecular redox reactions the oxidation and reduction occur in two different chemical elements that are in the same molecule. If the oxidation and reduction occur in the same chemical element, then we name it as disproportionation.
Figure 01: Chemical Process of a Redox Reaction
What are Disproportionate Redox Reactions?
Disproportionate redox reactions are chemical reactions where oxidation and reduction occur in the same chemical element of a single substrate molecule. In this type of reactions, a single substrate molecule works both ways, oxidizing and reducing half-reactions. Here, a part of the molecule undergoes oxidation while the other part of the molecule undergoes reduction; however, both these molecular parts involve the same chemical element in which oxidation or reduction occurs. An example is as follows:
Figure 02: An Example of a Disproportionate Redox Reaction
Another common example of this type of chemical reactions is the disproportionation of the oxygen atom in the hydrogen peroxide, H2O2 molecule. Here, the oxygen in hydrogen peroxide molecule undergoes oxidation to form oxygen gas, and the same molecule undergoes reduction to form a water molecule.
What is the Difference Between Intramolecular Redox and Disproportionate Redox Reaction?
Redox reactions are chemical reactions in which an oxidation half-reaction and a reduction half-reaction occur parallel to each other. The key difference between intramolecular redox and disproportionate redox reaction is that intramolecular redox reactions occur when molecules of two different substances react with each other whereas disproportionate redox reactions involve the oxidation and reduction of a single molecule.
Disproportionation of C6H2(NO2)3CH3 to form N2 via reduction and C via oxidation is an example of an intramolecular redox reaction while disproportionation of the oxygen atom in a hydrogen peroxide molecule is an example of a disproportionate redox reaction.
The below infographic summarizes the differences between intramolecular redox and disproportionate redox reaction in tabular form for side-by-side comparison.
Summary – Intramolecular Redox vs Disproportionate Redox Reaction
Redox reactions are chemical reactions involving oxidation and reduction reactions that take place parallel to each other. The key difference between intramolecular redox and disproportionate redox reaction is that intramolecular redox reactions occur when molecules of two different substances react with each other whereas disproportionate redox reactions involve the oxidation and reduction of a single molecule.
Reference:
1. Mott, Vallerie. “Types of Redox Reactions.” Lumen – Introduction to Chemistry, Available here.
2. Helmenstine, Anne Marie. “The Definition of Disproportionation in Chemistry.” ThoughtCo, Available here.