Czonolysis as a method for establishing the position of olefinic linkages

Abstract

Summary Ozonolysis and chromatographic procedures as a method for determining the position of double bonds in olefinic acids are not entirely satisfactory. Ozonolysis is seriously limited because of the secondary reactions undergone by the ozonide. Chromatographic resolution of the decomposed ozonides of oleic acid yields the expected pelargonic and azelaic acids but also yields fractions that indicate double bonds which do not exist. Fractions corresponding to pimelic, sebacic, caprylic, suberic, and capric acids appeared. The “pimelic acid” fraction resulted from the reaction of ozone with an oxidizable or hydrolyzable solvent such as acetone, methanol, or tetrachloromethane. The “sebacic” and “caprylic acid” fractions were incompletely decomposed ozonide. The suberic and capric acid fractions however were real and are believed to have resulted from 8‐octadecenoic acid present in the oleic acid in amounts too small to be detected by the methods used to establish its purity.

Water soluble reaction products from ozonolysis of grasses

“…Caproic acid results from the oxidation of the C-12 double bond in linoleic acid (Privett and Nickell, 1966). Azelaic acid could result from the oxidation of the C-9 double bond in either linoleic or linolenic acids (Benton et al, 1959). Malonic acid could be produced from the oxidation of the C-9 and C-12 or the C-12 and C-15 double bonds.…”

Reactions of the Hydrocarbon Chain of Fatty Acids.

“…Unfortunately, however, few investigators appear to have actually established the precision of their procedure for the analysis of mixtures of positional isomers of unsaturated fatty acids. One source of error apparently lies in failure to achieve clean decomposition of the ozonide (54). Another difficulty is in the separation of longerchain dicarboxylic acids (>Ci2) from monocarboxylic acids and in the chromatography of these dibasic acids (5).…”

Ozonolysis of Unsaturated Fatty Acids: I. Ozonolysis of Oleic Acid

“…Ozonolysis is an attractive technique owing t o the complete reaction of ozone with the starting material (8) and the simplicity of the reagents and procedures generally adopted. The chief disadvantages, other than the necessity of an ozone generator, have alwal~s been the nominal yields (70-85%) (10)(11)(12)(13)(14)(15)(16) of primary acidic fission products, the associated fornlation of carbonyl, peroxidic, and polymeric materials (1, 7 17), and the presence of one or more secondary acidic oxidation products. The latter can cause considerable uncertainty where minor amounts of positional isomers are being determined, while by-products hinder both separation and analysis of the products (10,18).…”

“…The chief disadvantages, other than the necessity of an ozone generator, have alwal~s been the nominal yields (70-85%) (10)(11)(12)(13)(14)(15)(16) of primary acidic fission products, the associated fornlation of carbonyl, peroxidic, and polymeric materials (1, 7 17), and the presence of one or more secondary acidic oxidation products. The latter can cause considerable uncertainty where minor amounts of positional isomers are being determined, while by-products hinder both separation and analysis of the products (10,18). Certain procedures do give high yields of products, but the silver oxide oxidation method of Asinger (3,12,19) and the procedure of Iclenl.…”