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Return to Abstracts of Literature 1500-1749
1715. KEIL, W. AND SCHILLER, G. [Fats From Fatty Acids With Odd Numbers of Carbon Atoms. Addendum to III, IV, and V.] Ztschr. Physiol. Chem., vol. 282, 1947, pp. 135-136; Chem. Abs., vol. 43, 1949, p. 6164.
Fats from fatty acids with odd numbers of C atoms whose metabolic fat in dogs has been reported, abs. 1714, were prepared by esterification with glycerol of the fatty acids resulting from air oxidation at 100°-150° of various paraffin preparations in the presence of suitable catalysts. The crude fatty acids were removed by extraction with aqueous alkali, reprecipitated by addition of mineral acid, distilled, and the fraction of chain-length C16-C23 esterified. The resulting triglycerides were purified in the usual way. The acids prepared from Riebeck-paraffin fatty acids contained higher oxidation products (I), especially dibasic acids (II) (3-4%), HO, and Keto acids. The color of the resulting fats, G138/140, was improved by hydrogenation. The acids prepared from Fischer-paraffin fatty acids, containing (I), gave the fat G137, which was hydrogenated before use. The acids prepared from a paraffin resulting from the high temperature hydrogenation of lignite or lignite tar gave, without further purification, G284 on esterification. G301 was prepared from the same material as G284, after careful separation of the fatty acids from (I), especially (II), by chromatography on silica gel, and improvement of the triglyceride color by hydrogenation. G236 was prepared from the same starting material as G137, but with purification of the acids by chromatography as for G301. Prior crystallization of the lignite paraffin and chromatography of the crude acids gave, on esterification, G405, a product free of (II), and branched-chain acids (III). The fatty acids resulting from oxidation of pure eicosane contained no (III), and chromatography removed (II); on esterification, G273a resulted, but omission of chromatographic treatment gave G289 which contained some (II). G118/119 are comparable to G138/140 and were prepared from the acids from oxidation of Riebeck paraffin.