Reactions in monolayers of drying oils II-Polymerization of the oxidized forms of the maleic anhydride compound of β-elaeostearin

Abstract

In part I it was shown that the preliminary stages in the "drying" of a monolayer of the maleic anhydride compound of β-elaeostearin extended on dilute acid substrates consisted in the formation of an unstable peroxide, which in turn could form either a stable isomer or be converted into a polymer. The stable isomer in turn was likewise found capable of undergoing polymerization. The evidence that the reaction subsequent to the formation of the peroxide is a species of polymerization is based upon the following observations. Films of β-elaeostearin when the reaction is completed are continuous and gel-like in nature; those of the maleic anhydride compound are highly viscous and cannot be extended without becoming inhomogeneous. It is clear that cross-linkage in the formation of the polymer is readily possible in β-elaeostearin; but this tendency is much reduced in the maleic anhydride compound, especially when the most probable molecular configuration is considered (Part I). [ Note added in proff, October 15, 1935.—The position of the reaction double bonds immediately above the double ring system must introduce difficulties in the formation of oxygen bridges during polymerization. As successive molecules are added, the bulky rings must be forced progressive outwards, causing both a progressive expansion of the film as the molecular complexity increase and a diminution in the case of addition of further molecule.