Oleic acid, infrared

The crude acid chloride will serve for most purposes. It can be distilled at very low pressures (b.p. 99-109°/25 ja) to yield a water-white product d 1.4580-1.4613 (Note 5). Small amounts of oleoyl chloride may be distilled at higher pressures b.p. 180-185°/l-2 mm. The infrared absorption curve of the oleic acid obtainable by hydrolysis is the same as that of the oleic acid used thus no isomerization during the reaction is indicated. 

V. H. W. Mak, R. O. Potts, and R. H. Guy. Oleic acid concentration and effect in human stratum corneum Non-invasive determination by attenuated total reflectance infrared spectroscopy in vivo. J. Control. Release 12 67-75 (1990). 

Solubilization of carboxylic acids, such as acetic acid and oleic acid, by dino-nylnaphtalenesulfonates (DNNS) in hexane was studied by infrared spectroscopy. Since DNNS salts form reverse micelles and have an aggregation number of approximately 7 in low polar solvents, carboxylic acids would be solubilized in the polar core of the RMs (Inoue and Nose, 1987 Inoue et al. 1965). 

The corrosive activity on copper/lead bearings for typical carboxylic acids, such as decanoic, lauric, palmitic, stearic, and oleic acids, as 1 % w/w solutions in a lubricating oil base stock with excess of hard-core RMs, measured by infrared spectroscopy, supports the observation for the corrosive activity of used lubricating oils. An increase in total acidic number (TAN) is generally either an indication of contamination with acidic combustion products or the result of oil oxidation. Corrosion of bearing metals by used lubricating oils requires the presence of both acids and peroxides and probably takes place by a two-step mechanism. In the first step, the peroxide reacts with the metal to form a metal... 

Wadsworth and coworkers (13, 14) have found considerable evidence for surface polarization in double-beam infrared spectroscopy. Not only do new differential peaks due to adsorption appear in the spectrograms but also the bands due entirely to the adsorbent are frequently appreciably shifted by adsorption. This occurred, for example, in calcium fluorite treated with oleic acid, in samples of bentonites taken from aqueous solutions of different pH, and in various minerals treated by flotation collectors. In fact, it is more the rule than the exception that the spectrograms of finely divided solids dispersed in the KI or KBr window exhibit distortion due to adsorption, whether adsorption occurs at the solid-aqueous solution or at the solid-vapor interface. For example, Eyring and Wadsworth (13) found that two (differential) peaks were produced by adsorption on willemite either from the vapor or aqueous solution of hexanethiol. These peaks were due to the influence of adsorption of the hexanethiol on the Si-O bands of the willemite and occurred at about 9.2 and 12.3 microns. 

Figure 14 Transmission infrared spectmm of porcine stratum comeum treated with perdeuterated oleic acid. (From Ref. 147.)...

Takeuchi, Y. et al. Effects of oleic acid/propylene glycol on rat abdominal stratum comeum lipid extraction and appearance of propylene glycol in the dermis measured by Fourier transform infrared/attenuated total reflectance (FT-IR/ATR) spectroscopy. Chemical and Pharmaceutical Bulletin 4/(8) 1434-1437, 1993. 

Using diffuse reflectance Fourier transform infrared spectroscopy, Adhikari et al. studied the binding of oleic acid (88), triacylglycerol (89), and phosphatidylcholine (90) on silica gel at room temperature. Their interpretation was that oleic acid and triacylglycerols bind to silica surface hydroxyls via hydrogen bonding interactions between the carboxylate and ester carbonyls of these molecules, respectively. In contrast, phospholipids hydrogen bond to silica surface hydroxyls via the phosphate... 

A, S. Peck and M. E, Wadsworth, Infrared Studies of Oleic Acid and Sodium Oleale Adsorption... 

One hundred and thirty-eight (138) oil samples were analyzed with visible (vis) and near-infrared (NIR) transflectance spectroscopy. Forty-six of them were Greek pure extra virgin olive oils and the same oils adulterated with 1% (w/w) and 5% (w/w) sunflower oil. However, no significant difference was found between the spectrum of pure sunflower oil and that of olive oil, which can be detected by the naked eye. Olive and sunflower oils differ in their composition principally in their content of linoleic and oleic acids. Accordingly, typical figures for olive oil were quoted at 12.3% and 66.3%, respectively, while for sunflower oil the corresponding mean values of 66.2% and 25.1%, respectively. 

The conversion of oleic acid to 10-D-hydroxystearic acid by a pseudomonad has been studied in a medium enriched in DjO (Schroepfer, 1966). The reaction occurred with stereospecific incorporation of one atom of solvent hydrogen at carbon 9. The location of the deuterium was established by a combination of chemical and mass spectrometric evidence. After extraction with ether and silicic acid column chromatography, crystals were obtained of 10-D-hydroxy-[9- Hi]-stearic acid. The presence of deuterium in the compound was indicated by a 2128 cm" C—D stretching band in the infrared spectrum of the free acid and of its methyl ester. The fingerprint region of the spectra differed significantly from that of the spectra of the corresponding undeuterated compounds (Table 15.1) as has been... 

LbL = layer-by-layer Ln = lanthanide LSS = liqnid-solid-solntion NIR = near-infrared NPs = nanoparticles OA = oleic acid ODE = octadecene PA = photon avalanche PAA = polyacrylic acid PAH = poly(allyIamine hydrochloride) PEI = polyethylenimine PSS = poly(sodium 4-styre-nesnlfonate) PVP = polyvinylpyrrohdone QDs = qnantum dot SAUCI = smaU-animal upconversion imager SHG = second-harmonic generation STPA = simultaneons two-photon absorption TOPO = trioctylphosphine oxide TPA = two-photon absorption UCNPs = Upconversion nanoparticle UV = nlfraviolet. 

Andre Weinstock, B. et al. (2006) Prediction of oil and oleic acid concentrations in individual corn (Zea mays L.) kernels using near-infrared reflectance hyperspectral imaging and multivariate analysis. Appl. Spectrosc.,... 

Pi, F.W., Shinzawa, H., Czarnecki, M.A., Iwahashi, M Suzuki, M. and Ozaki, Y. (2010) Self-assembling of oleic acid (cis-9-octadecenoic acid) and linoleic acid (cis-9, cis-12-octadecadienoic acid) in ethanol studied by time-dependent attenuated total reflectance (ATR) infrared (IR) and two-dimensional (2D) correlation spectroscopy. J. Mol Struct., 974, 40-45. 

In the near infrared region, the bands are not only weaker, they can be broader and more overlapping. For example, the near infrared spectrum of oleic acid... 

FIGURE 13 The near infrared spectrum of oleic acid run in a 1-mm cell with bands at 1723 nm (2x CH2 out-of-phase stretch) and 1758 nm (2x CH2 in-phase stretch). 

FIGURE 14 The second derivative of the near infrared of oleic acid (Fig. 13). Strong bands are seen at 1726 and 1761 nm (2x CH2 stretch) as seen in Fig. 13 but with bands pointing down. Bands not seen easily in Fig. 13 are seen here at 1711 nm (2x CH3 out-of-phase stretch) for the terminal CH3 and 1688 nm (2x =CH stretch) for the internal unsaturation. Negative side lobes on the sides of the strong bands are seen pointing up. 

This stearolic acid has been thoroughly characterized 3 6 by the freezing-point curve, ultraviolet and infrared spectra, ozonization, and hydrogenation. It has been shown to be free both of positional isomers and of olefinic acids such as oleic and elaidic acids. Its properties include m.p. 46-46.5°, iodine number (Wijs titration, 30 minutes) 89.5, d 5 1.4510, d 5 1.4484, neutral equivalent 279.2-279.6 (theory 280.4), hydrogen uptake 95-100% of theory for a triple bond. The last trace of color is difficult to remove by recrystallization from petroleum ether. It can be removed, however, by crystallization from a 20-30% solution in acetone at —5 to —8°, or from an 8-10% solution at —20°, or by distillation (b.p. 189-190°/2mm.). 

L. Velasco, B. Perez-Vich, J. M. Fernandez-Martinez. Nondestructive screening for oleic and linoleic acid in single sunflower achenes by near-infrared reflectance spectroscopy. Crop Sci 39-. 219-222, 1999. 

Marshall, K. and Rochester, C.H., Infrared Study of the Adsorption of Oleic and Linolenic Acids onto the Surface of Silica Immersed in Carbon Tetrachloride. J. Chem. Soc., Faraday Trans. I, [71] 1754 (1975). 

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