The reaction of beta-propiolactone with alpha-and beta-eleostearates and plasticizer properties of derived esters

Summary

Beta-propiolactone has been employed as the dienophile component in the Diels-Alder reaction withalpha- andbeta-eleostearates, yielding acrylic acid adducts. Catalytic amounts of potassium carbonate were used to induce polymerization ofbeta-propiolac-tone to a polyester and to assist in its pyrolysis to acrylic acid.

The ethyl andn-butyl esters of the mixed fatty acids ofalpha-and ofbeta-tung oil, containing about 75% eleostearates, were reacted with the theoretical amount ofbeta-propiolactone at 200°C. for a period of 1.5 hrs. Spectral analyses indicated nearly quantitative conversion of the reactants to the expected Diels-Alder products.

The acrylic acid adducts were esterified in their reaction mixtures with the appropriate alcohols to produce the corresponding di-esters. These esters were purified by means of high vacuum distillation.

Fractional crystallization of the free acids obtained by saponification of the di-butyl esters of thealpha-eleostearic acid adducts yielded two isomeric dicarboxylic acids, melting at 113°C. and 85°C. These isomers differ only in the position of the carboxyl group on the cyclohexene nucleus of the adduct.

The di-ethyl and di-butyl esters of both thealpha-andbeta-eleostearic acid adducts and their hydrogenated derivatives have been intercompared as primary plasticizers for vinyl type resins. The hydrogenated di-esters of thebeta-eleostearic acid adducts were found to be the most effective.