Acid oleic, elaidizing

Figure 14-5. Geometric isomerism of A , 18 1 fatty acids (oleic and elaidic acids).

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. 

Figure 11.10 Structure of ds-octadecenoic and trans-octadecenoic add (an example o/cis-trans isomerism). The common name for trans-octadecenoic acid is elaidic acid it is one of the few naturally occurring trans fatty acids. The common name for c/s-octadecenoic acid is oleic acid. Note that the two hydrocarbon chains are separated by the double bond which prevents rotation of the position of the two chains. The structure of the trans fatty acid is biochemically unusual and therefore biochemically excluded. ...

Fig. 1 HPLC of free fatty acids. Column SUPELCOSIL LC 18. 25 cm X 4.6-mm ID. (5fi) mobile phase tetrahydrofuran/acetonitrile/0.1% phosphoric acid, pH 2.2 (21.6 50.4 28.0) flow rate 1.5 ml/min temperature 35°C detection at 220 nm sample concentration 1-2 mg/ml per component. 16 1 (cis) = cis-9-hexadecenoic acid (cis-palmitoleic acid) 16 1 (trans) = trans-9-hexadecenoic acid (trans-palmitoleic acid) 18 0 = octadecanoic acid (stearic acid) 18 1 (cis) = cw-9-octadecenoic acid (oleic acid) 18 1 (trans) = trans-9-octadecenoic acid (elaidic acid) 18 2 (cis) = cis-9-cis-12-ctadecadienoic acid (linoleic acid) 18 2 (trans) = trans-9-trans-12-octadecadienoic acid (linolelaidic acid) 18 3 (cis) = cis-9-cis-2-cis-15-octadecatrienoic acid (linolenic acid).

Figure 2-3 Structures of Octadec-cis-9-Enoic Acid (Oleic Acid) and Octadec-trans-9-Enoic Acid (Elaidic Acid)...

The second pair of higher unsaturated acids exhibiting geometric isomerism is oleic acid and elaidic acid. Oleic acid is of especial importance because, as a glycerol ester, it occurs very commonly as a constituent of many animal and vegetable Jats and oils. While most... 

Position of Double Bond.—The position of the double bond and the full constitution of oleic acid and elaidic acid has been established by means of the products obtained by careful oxidation. It has been shown that when compounds containing a double bond are thus oxidized the effect is to split the compound at the double bond with the oxidation of each doubly linked carbon group to carboxyl. Now both oleic acid and elaidic acid on oxidation yield two acids, each containing nine carbon atoms. One is a mono-basic acid known as pelargonic acid, CsHit—COOH and the other is a di-basic acid, azelaic acid, HOOC—C7H14—COOH. The reaction is... 

CgHj CH CH(CH2)7C00H ibid CgH. CH CH(CH2)70H ibid CgHi CH CH(CH2)iiCOOH ibid trans-9 octadecenoic acid cis-9 octadecenoic acid trans-8 octadecenyl alcohol cis-8 octadecenyl alcohol trans-13 docosenoic acid CIS-13 docosenoic acid elaidic acid oleic acid elaidyl alcohol oleyl alcohol brassidic acid erucic acid... 

Triglycerides containing saturated fatty acids easily form a compact structure, when placed together, and form a solid at room temperature. Where the fatty acids contain double bonds in the usual cis conformation, the cis double bonds create bends in the fatty acid, which impair close packing, and result in a liquid (oil). Where the fatty acids are in the trans conformation, the ability to pack closely is in between triglycerides with saturated and cis fatty acids. Oleic acid, a cis fatty acid, is 18 1, as noted earlier. The corresponding 18 1 trans fatty acid is called elaidic acid. Elaidic acid is abbreviated as trans 18 1. 

Materials. High purity saturated fatty acids, cis- and trans-A9-octa-decenoic acids (oleic and elaidic acids) and 12-hydroxystearic acid, were obtained from Applied Science Laboratories. Trans-3-octadecenoic acid... 

It is important to realize, that within a certain lipid class there is still a very large number of individual lipid molecules, which can be formed by a great variety of combinations of two fatty acids differing in their chain length (carbon number), in unsaturation (number of C=C bonds) and in their position on the glycerol backbone (Cl or C2). For simplicity, fatty acids are often denoted by the number of carbon atoms number of C=C bonds, e.g. 18 0 for stearic, 18 1 for oleic/elaidic, 18 2 for linoleic, 18 3 for linolenic acids, etc. Any chemical manipulation on lipids of natural origin usually involves simultaneous reactions of quite a few similar but not identical substrate molecules. On the other hand, individual lipids may have specific biological role which -at least in principle- could be assessed by a selective chemical transformation or removal of a lipid of particular composition. 

Fluid cw-configured unsaturated fatty acids can easily be isomerized to the solid tmn -diastereomers (e.g., oleic acid to elaidic acid) by radicals such as nitrogen oxides. The trans-diastereomers are much more stable towards oxygen, because they co-crystallize with saturated neighbor chains and solid fats do not dissolve as much oxygen. They are, however, worthless as an essential foodstuff (Scheme 2.4,7). 

Epoxidation is a cis addition process so that oleic acid gives cw-epoxystearic acid and elaidic acid gives rran -epoxystearic add. Linoleic acid furnishes cis-9,10 cw-12,3-diepoxystearic acid. This exists in two (racemic) stereochemical forms which have been separated by crystallization. Partial epoxidation of methyl linoleate gives diepoxide, unreacted linoleate and a mixture of two mono epoxides (cw-9,10 epoxy 18 112c and cw-12,13-epoxy 18 1 9c). 

Another example of monoene isomerization is a cis-trans isomerase identified in some aerobic bacteria that convert oleic acid to elaidic acid as a protective mechanism. This cis-trans isomerase is constitutively present in Pseudomonas (35) and converts oleic add to elaidic acid to alter its membrane permeability for protection from growth inhibitors such as toxicants (36) or extremes in ambient temperature (37). The isomerase exhibits regiospecificity, where the active site of the enzyme penetrates to a spedfic depth in the membrane. Thus, enzyme activity is sensitive to changes in membrane fatty acid composition and fluidity (35) and does not require ATP or cofactors such as NAD(P)H. 

So, maleic anhydride Diels-Alder addition products to (conjugated) linoleic acid (CLA, Figure 3B.16, a.) may be prepared both with and without catalytical amounts of iodine, clay, or silica at a reaction temperature generally from about 100°C to about 230 °C. Similarly, the Diels-Alder addition of acrylic acid yields a C21-diacid (Figure 3B.16, b.). Under somewhat more vigorous conditions, the monounsaturated oleic/elaidic acids react with maleic anhydride at 215 °C to about 250 °C to form an ene-adduct (Figure 3B.16, c.). Diels-Alder and ene reaction products ofTOFA form polyfunctional carboxylic acids that can further be sulfonated by reaction with sulfuric acid and/or can undergo esterification or amidation reactions. - ... 

Oleic acid and elaidic acid are isomeric alkenes ... 

Oleic acid, a major component of butter fat, is a colorless liquid at room temperature. Elaidic acid, a major component of partially hydrogenated vegetable oils, is a white solid at room temperature. Oleic acid and elaidic acid can both be prepared in the laboratory by reduction of an alkyne called stearolic acid. Draw the structure of stearolic acid, and identify the reagents you would use to convert stearolic acid into oleic acid or elaidic acid. 

Hanis, T. Smrz, M. Khr, P. Macek, K. Klima, J. Base, J. Deyl, Z. Determination of fatty acids as phenacyl esters in rat adipose tissue and blood vessel walls by high-performance hquid chromatography, J.Chromatogr., 1988, 452, 443-457. [derivatization LOD 0.8-1.2 ng column temp 40 caproic acid caprylic acid capric acid lamic add myristic acid myristoleic acid pentadecanoic add palmitic acid palmitoleic acid heptadecanoic acid stearic acid oleic acid elaidic acid linoleic acid Unoelaidic acid eicosenoic acid eicosadienoic acid eicosatrienoic acid arachidonic acid emcic acid docosahex-aenoic acid]... 

Miwa, H. Yamamoto, M. Liquid chromatographic determination of free and total fatty acids in milk and milk products as their 2-nitrophenylhydrazides, J.Chromatogr., 1990, 523, 235-246. [milk butter cheese condensed milk ice cream gradient column temp 35 LOD 0.5-2 pmol lactic acid acetic acid propionic acid isobutyric acid butyric acid isovaleric acid valeric acid 2-ethylbutyric acid isocaproic acid caproic acid capiyhc acid capric acid lauric acid myristoleic acid eicosapentaenoic acid linolenic acid myristic acid docosahexaenoic acid pahnitoleic acid arachidonic acid linoleic acid linoelaidic acid eicosatrienoic acid palmitic acid docosatetraenoic acid oleic acid elaidic acid eicosadienoic acid margaric acid docosatrienoic acid stearic acid eicosaenoic acid docosadienoic acid arachidic acid erucic acid]... 

Pei, P.T.-S. Kossa, W.C. Ramachandran, S. Henly, R.S. High pressure reverse phase liquid chromatography of fatty acid p-bromophenacyl esters. Lipids, 1976, 11, 814-816. [linoleic acid derivatization linolenic acid linoleaidic acid oleic acid elaidic acid stearic acid palmitoleic acid palmitelaidic acid petroseUnic acid]... 

Ryan, P.J. Honeyman, T.W. Determination of fatty acids by higji-performance liquid chromatography of Dns-ethanolamine derivatives, J.Chromatogr., 1984, 312, 461-466. [derivatization fluorescence detection bulk linolenic acid palmitoleic acid linoleic acid eicosadienoic acid palmitic acid oleic acid elaidic acid margaric acid arachidonic acid]... 

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