NATURALLY OCCURRING EPOXY OILS

Fatty acids containing oxirane functional groups have unexpectedly been found in wide distribution in seed oils, usually present as longchain glycerides. Four such acids have been discovered:cis- and trans-9,10-epoxystearic acid; vernolic (cis-12,13-epoxyoleic) acid; coronaric acid, isomeric with vernolic acid but with the oxirane and double-bond functions in the reverse positions; and cis-15,16-epoxylinoleic acid. No single analytical tool has been universally successful in measuring the oxirance content of epoxides. This appears to be caused by the way in which the chemical reactivity of the three-membered cyclic ether is modified by molecular structure and by the presence of nearby substituents. A survey of the published methods for the determination of oxirane functions, including mention of the nature of interfering substances, is given. Techniques used to overcome some of these difficulties are discussed. These procedures include the use of chromatographic and spectrophotometric procedures to solve some of the analytical problems which are encountered. Special consideration is given to vernolic acid and its glycerides since this is the most widely distributed and abundant epoxy acid found in seed oils to date. © 1968 The American Oil Chemists' Society.