The volatile decomposition products and the organoleptic characteristics of the oxidative polymers of ethyl linoleate

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Abstract
Summary: The polymers formed during autoxidation of ethyl linoleate at 30°C. were isolated by a solvent extraction method using pentane‐hexane and diethyl ether as solvents. These polymers were only partially decomposed by catalytic hydrogenation at temperatures ranging from 25 to 110°C. and pressures ranging from 60 to 1,800 p.s.i. with Raney Nickel as catalyst. Both the polymers and their hydrogenated products had a bitter rancid flavor and painty odor. However in a dilution up to 10 parts per million, the polymers as well as the hydrogenated polymers could not be detected organoleptically.Both the polymers and their hydrogenated products were reautoxidized at 30°C. and the volatile material obtained in each case characterized. The volatile material which was obtained from the polymers contained n‐propionaldehyde, n‐pentanal, and n‐hexanal; and the volatile material from the hydrogenated polymers contained n‐pentanal and 2‐heptenal. Since n‐hexanal was also identified in the volatile decomposition products from autoxidizing soybean oil and 2‐heptenal from the reversion compounds of hydrogenated soybean oil and since both these aldehydes were absent in the volatile cleavage products from autoxidizing linolenate, it is therefore possible that these reversion compounds could have arisen from the oxidative polymers of linoleate.