A Study of Some Animal and Vegetable Fats

Part I: Analysis of Animal Fats Many investigators in this field have compared the relative abundance of vegetable fat analyses with the scant information available on animal fats and have stressed the need for further analyses of the fats from a wider variety of animals. This study is concerned with the analyses of eight animal fats via. those from crocodile, ostrich, flamingo, rabbit, mouse, porcupine, antelope and sea lion. The results obtained have been compared with those derived from the fats of related animals, showing that in general, the fats become simpler in the orders aquatic animals → amphibia→reptiles→birds and rodents→land animals. The effect of diet and other circumstances on the composition of animal fats is discussed, and a general survey of the animal fats so far analysed indicates that there is a correlation between I.V. of the fat and fatty acid composition. Expressions have been derived for fats of I.V. less than 90 which will give the approximate composition of the fat, using the I.V. only. Part II: Separation and Identification of Unsaturated Acids A number of animal fats are characterised by complex mixtures of polyethenoid acids, and as yet no satisfactory method has been evolved for separating and identifying them. Assuming that a polyethenoid acid could be separated free of all major impurities, the problem of determining its structure was discussed and a method providing unambiguous results was investigated. This method involved a system of partial hydroxylation and was successful in the ease of methyl linoleate. Further development is required, however, before this method can be applied to other more unsaturated acids. In the course of this work a micromethod of analysing mixtures of mono-and dicarboxylic acids by partition chromatography was developed. Several attempts were made to separate polyethenoid acids from a sample of crocodile fat in a sufficiently pure state for characterisation. Various techniques such as fractional crystallisation, fractional distillation, chromatography and formation of urea complexes were utilised, but none of them was entirely successful. Part III: The Constitution and Properties of Santalbic Acid Santalbic acid, the chief component acid in Santalum album (Linn.) seed oil is shown to be trans-octadec-11-en-9-ynoic acid, and thus identical with ximenynic acid. Some reactions of the acid and its derivatives are investigated