I. Analysis of Animal Fats. II. Cyclisation in the Friedel-Crafts Ketone Synthesis. With an Addendum on the Structure of Byssochlamic Acid

Paton, Robert P (1953) I. Analysis of Animal Fats. II. Cyclisation in the Friedel-Crafts Ketone Synthesis. With an Addendum on the Structure of Byssochlamic Acid. PhD thesis, University of Glasgow.

Abstract

The work done on the fats of oxen, pigs, the white rat, etc., to determine the effect of diet, age, sex, etc., on their depot fatty acids is of the greatest importance. Herein lies the main difference between vegetable and animal fats. The ultimate aim, of course, would be the fat composition in the various sites as has been done with oxen, pigs, etc., but by present procedure this would be Impossible in the case of small animals unless by accumulated samples from a number of individuals. The initial stage, that of obtaining samples of the less common animals, has been overcome, as stated above, by the cooperation of zoological authorities and other sources. About twenty samples of a wide variety have been sent to us during a year and these have been extracted and stored in a refrigerator for future work. Treatment prior to extraction of these samples required investigation since the presence of disease in some of the tissues made sterilisation desirable. Apparatus has been designed for extraction of animal fats varying from hard tallows to liquid fish oils. This procedure was quite different from the seed oil method since tissue is often tough and resistant to breakdown. As some of the samples were too small for analysis by standard procedure, considerable time was spent in testing the reliability of the usual methods on the small scale, and the use of approximately 0.6 g. for the saponification equivalent measurement has given satisfactory results. Mixtures of fatty acids similar to those in animal fats have been subjected to low temperature crystallisation and the optimum conditions found. Crystallisation from methyl alcohol at -20 has proved as effective and less troublesome than the usual lead salt separation of saturated from unsaturated acids. The technique has been improved and a low temperature cabinet for better control of conditions is being made. The efficiency of two fractionating columns (Towers and Dixon) in separating various quantities of mixed esters has been investigated. It has been shown that fractional distillation of small quantities (12 g. and 6 g.) with subsequent use of the semi-micro technique for the saponification equivalent gave results almost identical with those obtained by distilling larger quantities (40 g. and 25 g. ) of the same ester mixture. The analysis of three fats has been carried out using the Hilditch procedure modified by the above preparatory work. The method of analysis is to hydrolyse the fat, extract the mixed acids and subject these to low temperature fractional crystallisation to give three or more fractions. These are then esterified and fractionally distilled to twelve or more ester fractions each. The saponification equivalent, iodine value and weights of the ester fractions combined with alkali isomerisation data provide the information for calculation of the acid composition. This is followed by identification of each acid present in appreciable amounts and concentrated by the fractionation during analysis. Except in one case the fatty acids identified in these fats were all the usual acids occurring in seed oils. This was a hexadecenoic acid found in deer fat which gave a dihydroxy derivative having a different melting point from that of the usual one. A hexadecenoic acid giving a dihydroxy derivative of the same melting point as the deer fat derivative has been isolated from spemn oil , but the position of the double bond was not determined. (Abstract shortened by ProQuest.).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Organic chemistry
• Date of Award: 1953
• Depositing User: Enlighten Team
• Unique ID: glathesis:1953-79089
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 05 Mar 2020 11:44
• Last Modified: 05 Mar 2020 11:44
• URI: https://theses.gla.ac.uk/id/eprint/79089