Oleic acid, unsaturation test

Lennarz and Bloch (1960) have prepared 9-hydroxystearic acid-H from naturally occurring J -9-hydroxyoctadecenoic acid by catalytic hydrogenation, and racemic 10-hydroxystearic acid through epoxidation of oleic acid, and tested them as possible precursors to olefinic acids in two ways. Both were as efficient as oleic acid in satisfying the unsaturated fatty acid growth requirement of yeast raised under strictly anaerobic conditions, suggesting that they were desaturated to olefinic acids in vivo. 9-Hydroxystearic acid-H in addition was incubated with yeast homogenate in the presence of TPNH, ATP, and CoA, and yielded a monounsaturated acid with a double bond in the vicinity of C-8 to C-10. 

The results of this test demonstrated that the diamides of the Ci4 and higher saturated fatty acids were water repellents. On the other hand, the unsaturated oleic acid derivatives enhanced hydrophilicity. 

A peach coloured oil with a delicate nutty aroma. Emollient and highly nourishing it is particularly suited to dry and mature skins. It is unusual in that it is comparatively high in the unsaturated fatty acids oleic acid (55-67%), pal-mitoleic acid (18-25%), palmitic acid (7.0-9.5%), stearic acid (2.0-5.5%) and myristic acid (0.6-1.6%). It has good keeping properties, as it is quite resistant to oxidation. There are no reported irritation or allergy reactions in skin testing. 

G) Test for Unsaturation. Dissolve 0.4 g (or 7-8 drops) of the fatty acid mixture in 3-4 ml of carbon tetrachloride. Add from a burette, drop by drop, one per cent solution of bromine in carbon tetrachloride until the color of bromine persists even with shaking. Repeat, using about the same amount of stearic and oleic acid. 

Up until now, mostly pure substrates such as methyl oleate and its -isomer, methyl elaidate, have been tested as model substrates for hydroformylation, but in a few cases, linoleates, linolenates, and esters of ricinoleic acid have also been investigated (Figure 6.10). Oleic acid can be derived from new sunflower, linoleic acid from soybean, linolenic acid from linseed, and ricinoleic acid from castor oil. The long-chain mono-unsaturated fatty acid erucic acid (C22) can be extracted from old rapeseed oil. 

BETA derivatives of C9-C22 saturated fatty acids, as well as the Cig unsaturated acids, oleic and elaidic, were prepared and evaluated in the previous publication (11). Hydrophobicity determination, via contact angle measurements, proved to be nondiscriminatory and, therefore, a more meaningful test, the sand penetration test was devised. 

Previously, the strain DS5 bioconversion products from oleic and linoleic acids were identified as 10-ketostearic (23) and 10-hydroxy-12(Z)-octadecenoic acid(24), respectively. It is interesting to find that all unsaturated fatty acids tested are hydrated at the 9,10 positions with the oxygen functionality at C-10 despite their varying degree of unsaturations. DS5 hydratase was not active on saturated fatty acids and other non-9(Z)-unsaturated fatty acids such as elaidic [9(.B)-octadecenoic], arachidonic [5( ),8( ),1 l( ),14( )-eicosatetraenoic], and erucic [13( )-docosenoic] acids (25). From all of the data gathered, it is concluded fliat DS5 hydratase is indeed a C-10 positional-specific enzyme. The fact that elaidic acid was not hydrated indicates that die unsaturation must be in flie cis configuration for DS5 hydratase activity. 

Tall oil fatty acids n. Class of products generally containing 90% or more fatty acid obtained by ffactionization of crude tall oil The fatty acids are a mixture of oleic and linoleic acids with lesser amounts of saturated and other unsaturated fatty acids. The remainder consists of rosin and neutral materials. Paint pigment, drying oils, polymers, resins, naval stores, cellulo-sics esters, and ink vehicles, vol 3. American Society for Testing and Material, 2001. 

The vegetable oils tested in this study contained mostly palmitic, oleic, and linoleic, with lower concentrations of other fatty acids. Some vegetable oils, notably palm and coconut oils, are cloudy or solid at room temperature due to high amounts of saturated fatty acids (50.0% and 91.2% total saturated fatty acids in pahn and coconut oil, respectively). This makes them poor candidates for low-temperature lubricant applications (table 14.2). On the other hand, the other vegetable oils in this study had 25% or lower total saturates, or conversely, these oils had 75% or higher total unsaturated fatty acids. High concentrations of unsaturated components impart the liquid character to these oils. 

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