Sign In

20.14 : Radical Autoxidation

The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether distillation, making them dangerous to use. Naturally occurring fats and oil, like vegetable oil, can also undergo autoxidation. These oils are generally a mixture of triglycerides, which consist of three long hydrocarbon chains with double bonds.

Figure1

Typically, the allylic position of triglycerides gets oxidized to form hydroperoxides that are responsible for the foul smell of foods containing unsaturated oils. Consequently, foods with unsaturated oils have a short lifetime unless radical inhibitors are used to inhibit the radical formation. These radical inhibitors, such as BHT and BHA, are used as food preservatives. Both BHT and BHA react with radicals to form resonance stabilized radicals. Additionally, the tert-butyl groups of these compounds sterically hinder the radical center and decrease the reactivity of the radicals. Thus, these radical inhibitors are called antioxidants, as they scavenge and destroy radicals.

Figure2

One can also find several natural antioxidants that help prevent the oxidation of cell membranes and biologically important compounds. For example, vitamin E and vitamin C are natural antioxidants. These compounds react with the reactive radicals to form less reactive and stabilized radicals.

Figure3

Tags
AutoxidationOrganic CompoundsHydroperoxideEthersRadical FormationTriglyceridesUnsaturated OilsRadical InhibitorsBHTBHAAntioxidantsVitamin EVitamin CFood PreservativesPeroxide Formation

From Chapter 20:

article

Now Playing

20.14 : Radical Autoxidation

Radical Chemistry

1.9K Views

article

20.1 : Radicals: Electronic Structure and Geometry

Radical Chemistry

3.6K Views

article

20.2 : Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals

Radical Chemistry

2.2K Views

article

20.3 : Radical Formation: Overview

Radical Chemistry

1.9K Views

article

20.4 : Radical Formation: Homolysis

Radical Chemistry

3.1K Views

article

20.5 : Radical Formation: Abstraction

Radical Chemistry

3.2K Views

article

20.6 : Radical Formation: Addition

Radical Chemistry

1.5K Views

article

20.7 : Radical Formation: Elimination

Radical Chemistry

1.5K Views

article

20.8 : Radical Reactivity: Overview

Radical Chemistry

1.7K Views

article

20.9 : Radical Reactivity: Steric Effects

Radical Chemistry

1.8K Views

article

20.10 : Radical Reactivity: Concentration Effects

Radical Chemistry

1.4K Views

article

20.11 : Radical Reactivity: Electrophilic Radicals

Radical Chemistry

1.7K Views

article

20.12 : Radical Reactivity: Nucleophilic Radicals

Radical Chemistry

1.9K Views

article

20.13 : Radical Reactivity: Intramolecular vs Intermolecular

Radical Chemistry

1.6K Views

article

20.15 : Radical Oxidation of Allylic and Benzylic Alcohols

Radical Chemistry

1.7K Views

See More

JoVE Logo

Privacy

Terms of Use

Policies

Research

Education

ABOUT JoVE

Copyright © 2025 MyJoVE Corporation. All rights reserved