Study of the radical mechanism of iodine-catalyzed isomerization of conjugated diene systems

The iodine-catalyzed Z/E-isomerization of internal conjugated dienes in the dark, to form a thermodynamic equilibrium mixture, was found to be a radical process with an activation energy of 12.4±1.2 kcal/ mol. The effects of antioxidants on the reaction, both in the dark and in sunlight, were studied. In both processes the radical isomerization was slowed down, probably through radical scavenging.