Quantitative Spectral Analysis of Fats

Isomers of linoleic acid. Infrared and ultraviolet properties of methyl esters

“…a ~ 90.5 calculated for the acid or 86.0 for the methyl ester, when alkali isomerized (KOHglycerol, 180 ~ , 30 minutes). This value is some 4% higher than the value (87.1 calcd, to acid) reported by Mitchell et al (9) for methyl linoleate made by debromination, without crystallization (isomerized in KOH-glycol, 180 ~ 25 minutes). Riemenschneider et al (13) comment on the probable presence of cistrans isomers and the possible errors in using debromination linoleate as a standard.…”

“…Pure non-conjugated linoleate is essentially transparent in the near ultraviolet while conjugated linoleate absorbs strongly at 230-233 m~. Alkali conjugation of normal cis-9, cis-12 linoleate has been made the basis of analytical methods (1,2,9).…”

The aromatization of linoleic acid with palladium catalyst

“…The effect of alkaline builders on the surface-active properties of typical detergents has been the subject of much research activity; for example, Harris (8), Merrill and Getty (9), Niven and Gadberry (10), and Morrisoe and Newhall (11) have shown that builders markedly enhance the surface activity of dilute synthetic detergent solutions and also improve detergent action, in a synergistic fashion, especially with polyphosphates. In order to utilize this synergistic behavior, commercial laundry materials are heavily built with alkaline salts.…”

“…=43.9; ~ 233 after isomerization=l.5 (no peak)(11). Methyl linoleate was prepared from the methyl esters of safflower oil by exhaustive treatment with urea in methanol.…”

The Chemistry of the Lipids

“…Brice & Swain (29) in attempting to apply the methods previously mentioned (24,27) to materials havirig very low proportions of non conjugated polyethenoic fatty acids encountered a number of difficul ties: the development of a strong and variable ultraviolet absorption on heating in ethylene glycol with potassium hydroxide in air; rela tively high background absorption by extraneous compounds; and, in mixtures in which the ratio of conjugated (diene) to nonconjugated compounds is high, the question as to what happens to the conjugated constituents during the isomerization treatment. Their modified method comprises measurement of the absorption of the sample before and after isomerization; the use of a more suitable solvent, glycerol ; correction of the data for extraneous absorption; correction of the data for conjugated constituents originally present and remaining un destroyed by the isomerization; and calculation of the proportions of conjugated and nonconjugated diene, triene, and tetraene fatty acid constitue n ts in the· sample.…”