Abstract
When linseed oil and α- or β-eleostearic acid obtained from tung oil were heated, it is known that cyclic monomers are produced. But there are many unclear points about the cyclic structure.
In this study, in order to identify the cyclic monomeric structure which was prepared from heated C18 trienoic acid, a methyl 10- (o-ethylphenyl) decanoate and its hydrogenate; methyl 10- (2'-ethyl cyclohexyl) decanoate; were synthesized. Bromination of ethylbenzene according to the method of Lamneck gave ortho-bromo-ethylbenzene, and which was reacted with magnesium in dry ether to give Grignard reagent. The organocadmium reagent was prepared by the addition of anhydrous cadmium chloride powder directly to the Grignard Reagent. Methyl (9-chloroformyl) -nonanoate prepared from sebacic acid was reacted with the organo-cadmium reagent and gave methyl 9- (2'-ethyl-benzoyl) nonanoate. After the reduction of the carbonyl group in the methyl 9- (2'-ethyl-benzoyl) nonanoate, methyl 10- (o-ethylphenyl) decanoate was obtained by methylation of the reduction product. Methyl 10- (2'-ethylcyclohexyl) decanoate was derived from methyl 10- (o-ethylphenyl) decanoate following the hydrogenation in ethyl acetate using palladium-black catalyst under high pressure and temperature of 200°C.
When methyl 10- (o-ethylphenyl) decanoate were compared by G.L.C. with the cyclic monomer produced by heated methyl α- or β-eleostearate at 250°C for 10 hours, it was identified that synthesized compound was the one component of the cyclic monomers.
