Infrared spectra hexane

Infrared spectrum, benzaldehyde, 730 butanoic acid, 771 cyclohexane., 436 cyclohexanol, 633 cyclohexanone, 730 cyclohexene. 436 cyclohexylamine, 952 diethyl ether, 671 ethanol, 421 hexane. 424 1-hexene, 424 1-hexyne, 424 phenol, 633... 

Figure 5. Infrared spectrum of pyrethrin II Fraction isolated from silicic acidr-acetonitrile-hexane partition column...

Figure 7. Infrared spectrum of pyrethrin I Isolated after dual partition chromatography First partition column. Celite-acetonitrile-hexane Second partition column. Silicic acid-nitromethane-hexane (with 5% acetone). Corresponds to peak 3 of gas chromatographic separation of pyrethrum mixture...

Figure 8. Infrared spectrum of a cinerin I type Fraction isolated from Celite-acetonitrile-hexane partition column and rechromatographed on a silicic acid-nitrome-thane-hexane (with 5% acetone) partition column.

Implementation A spectrum of the filtered coconut oil (Fig. 21.5) is obtained and subtracted from the spectrum of the oil containing the haze (solid) (Fig. 21.6). The haze in the crude coconut oil is filtered out of the oil and washed with hexane to remove residual oil. An infrared spectrum of the residue is obtained (Fig. 21.7). The spectra are essentially equivalent (Fig. 21.8). Identification is obtained by search against... 

Fig. 21.7. Infrared spectrum of the filtered and hexane rinsed solid material (haze) from the coconut oil.

Materials and Methods. The isomeric compositions of the four polybutadienes used are listed in Table I. Samples were prepared for infrared measurement from solutions of the polymer without further purification. Most films were cast from carbon disulfide solutions on mercury or on glass plates, but a few films were cast from hexane solutions to determine whether or not the solvent affected the radiation-induced behavior. No difference was observed for films cast from the different solvents. The films were cured by exposure to x-rays in vacuum. (Doses were below the level producing detectable radiation effects.) They were then mounted on aluminum frames for infrared measurements. The thicknesses of the films were controlled for desirable absorbance ranges and varied from 0.61 X 10 s to 2 X 10 3 cm. After measuring the infrared spectrum with a Perkin-Elmer 221 infrared spectrophotometer, the mounted films were evacuated to 3 microns and sealed in glass or quartz tubes (quartz tubes only were used for reactor irradiations). 

Carboxy-3,4-dibromodecanoic acid. This reaction should be carried out in a fume cupboard. Place 5.3 g (0.025 mol) of 3-carboxydec-3-enoic acid, 6.0 g (0.038 mol) of bromine and 60 ml of carbon tetrachloride in a 100-ml round-bottomed flask equipped with a magnetic stirrer and reflux condenser. Irradiate the stirred mixture with a 100-watt lamp for 6 hours the dibromide forms and precipitates out during this period. Filter the product with suction and wash thoroughly with hexane. The yield of 3-carboxy-3,4-dibromodecanoic acid is 7.9 g (85%). The acid can be recrystallised from toluene, m.p. 142— 143 °C. The infrared spectrum shows absorptions at 3400-2400cm-1 (O—H stretch of C02H) and 1730 cm-1 (0=0). 

The solid-state structure of Ru3CoH3(CO),3 was shown by X-ray crystallography to have C3v symmetry (38) (81). However, infrared and H-NMR spectroscopy showed that more than one isomer of this cluster exists in solution. The C3v structure 38 has no bridging carbonyls, but the infrared spectrum of the cluster in hexane solution showed vco at 1878 cm-1. XH-NMR measurements at -100°C and 360 MHz confirmed the presence of two isomers and showed that the second isomer contains three nonequivalent hydrogens. Structure 39 was suggested for the second isomer. At elevated temperatures, these isomers interconvert (Tc = -40°C). 

Rhodium complex was loaded onto the quatemised polymer support by the reaction with [Rh(CO)2I]2 in hexane (Eq 2). The resulting polymer beads or films showed the characteristic yellow colour of [Rh(CO)2I2] . An infrared spectrum of the powdered beads (KBr disk) showed two weak v(CO) absorptions of similar intensity at 2056 and 1984 cm 1, consistent with the presence of the cis-dicarbonyl complex, [Rh(CO)2I2]" (2059, 1988 cm 1 in CH2C12). Spectra of a much higher quality and intensity were obtained from polymer films loaded with rhodium complex. These observations of polymer supported [Rh(CO),I,r match those reported in the original study of Drago et al. 

Pentacarbonyl(methoxymethylcarbene)chroniiuin(0) is a dull-yellow, crystalline solid mp 34°. It slowly decomposes in the solid state at room temperature in air, but may be stored at 5° for a few days before appreciable decomposition is observed. It is soluble in aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and other common laboratory solvents such as benzene, 1,4-dioxane, tetrahydrofuran, chloroform, dichloromethane, and methanol, and is slightly soluble in ethanol. The infrared spectrum (cyclohexane solution) has v(CO) bands at 2065, 1985, 1965, and 1950 cm-1. The H nmr spectrum in chloroform-d shows the methoxy proton resonance at t6.15 and the methyl proton resonance at t7.70. Other physical properties are reported in the literature.6,7... 

Identification The volatile oil distilled from an oleoresin is similar in its physical and chemical properties, including its infrared spectrum, to that distilled from the spice of the same origin. To obtain the volatile oil from the oleoresin, proceed as directed under Volatile Oil Content, Appendix VHI. Residual Solvent Chlorinated Hydrocarbons (total) Not more than 0.003% Acetone Not more than 0.003% Isopropanol Not more than 0.003% Methanol Not more than 0.005% Hexane Not more than 0.0025%. 

A method for identifying chlorinated insecticide residues in fish tissue is described. Whereas electron capture gas chromatography guides the isolation procedures and provides tentative identification and quantitative estimation, positive identification is made on the basis of the infrared spectrum of isolated insectiQides. The procedure consists of hexane extraction of fish tissue, partition between hexane and acetonitrile, column adsorption and thin layer chromatography cleanup, and micro-infrared analysis in a potassium bromide disc. The practical limit of sensitivity needed to provide excellent infrared spectra of a number of the more common chlorinated insecticides is about 1 p.p.m. in the fish tissue concentrations as low as 0.25 p.p.m. have given informative infrared spectra. 

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