Reaction in monolayers of drying oils I - The oxidation of the maleic anhydride compound of β-Elaeostearin

Abstract

The mechanism by which a film of a drying oil becomes converted in the course of drying to a hard solid, and in particular the role played by oxygen, is still a matter requiring elucidation. The original hypothesis of a direct oxidation has been replaced by a process involving a primary oxidation followed by a polymerization of the formation of hydroxy ketones which condense with the elimination of water. The work of Elm, and especially of Morrell, suggests that the oxidation product which polymerizes is a peroxide, although the lability of this peroxide seems well established by the identification of dihydroxy and ketol bodies. ─CH─CH─ ─C = C─ ─C─CHOH │ │ ⇌ │ │ ⇌ ║ O ─ O OH OH O Staudinger further considers the peroxide to be preceded by a less stable moloxide ─CH─CH─, and evidence for the existence of some such unstable / O : O body has been presented by Hilditch and Lea in the oxidation of methyl oleate.