Spectra carbon disulfide

The use of aromatic solvents was unsuitable for this spectroscopy even at the highest temperature, 110° C, because of the lack of fine detail in the spectra. Carbon disulfide gave suitable separation of the various methyl proton resonances. Nonetheless, it was unacceptable because of its low boiling point. In addition, a comparison of the spectra obtained in carbon disulfide and carbon tetrachloride indicates that some secondary resonances in the methyl proton region are not resolved in carbon disulfide. With carbon tetrachloride at higher temperature the resonances were less distinct. Separation of the methyl proton resonances was poor with hexachlorobutadiene at room temperature but increased as the temperature increased. The secondary resonances noted using carbon tetrachloride were also visible. Experience with a number of samples indicated that... 

More complicated molecules, with two or more chemical bonds, have more complicated absorption spectra. However, each molecule has such a characteristic spectrum that the spectrum can be used to detect the presence of that particular molecular substance. Figure 14-17, for example, shows the absorptions shown by liquid carbon tetrachloride, CCfi, and by liquid carbon disulfide, CS2. The bottom spectrum is that displayed by liquid CC14 containing a small amount of C. The absorptions of CS2 are evident in the spectrum of the mixture, so the infrared spectrum can be used to detect the impurity and to measure its concentration. 

Extracts of these fat samples were treated with sodium sulfate-concentrated sulfuric acid mixture and fuming acid by the method described by Schechter et al. 5) in order to separate the organic-chlorine compound from the fatty materials. An infrared spectrum from 7 to 15 microns on carbon disulfide solutions of the residues from the fat qualitatively identified the organic-chlorine compound as toxaphene. All the bands of toxaphene in this spectral region were plainly seen in the treated steer extract, whereas none of the absorption bands were visible in the untreated steer extract. 

The solvents and coupling reagents were reagent grade materials. The tricaprylmethylammonium chloride (Adogen 464) was not purified further. Intrinsic viscosities were measured in chloroform at 25. Infrared spectra for hydroxyl analysis were measured on 2.5% solutions in carbon disulfide (vs. carbon disulfide2.in a cell with a 1.00 cm path length. The absorbance at 3610 cm was subtracted from a similar spectrum of 2 which had been quantitatively acetylated. 

The type of arrangement of the monomeric units in polymeric dienes can be determined qualitatively and quantitatively by IR spectroscopy. For this purpose thin films are prepared by dropping an approximately 2% solution in carbon disulfide (spectroscopically pure) on to suitable rock salt plates and allowing the solvent to evaporate at room temperature.The plates are placed in the spectrometer beam and the IR spectrum is recorded.The different types of chemical linkages are associated with characteristic IR bands as summarized in Table 3.9. 

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). 

FIGURE 3.3. Infrared spectrum of cyclopentanone in various media. A. Carbon tetrachloride solution (0.15 M). B. Carbon disulfide solution (0.023 M). C. Chloroform solution (0.025 M). D. Liquid state (thin films). (Computed spectral slit width 2 cm-1.)... 

The solvent selected must be dry and transparent in the region of interest. When the entire spectrum is of interest, several solvents must be used. A common pair of solvents is carbon tetrachloride (CC14) and carbon disulfide (CS2). Carbon tetrachloride is relatively free of absorption at frequencies above 1333 cm-1, whereas CS2 shows little absorption below 1333 cm-1. Solvent and solute combinations that react must be avoided. For example, CS2 cannot be used as a solvent for primary or secondary amines. Amino alcohols react slowly with CS2 and CC14. 

Stoicheff investigated the pure rotational Raman spectrum of CS2. The first few lines could not be observed because of the width of the exciting line. The average values of the Stokes and anti-Stokes shifts for the first few observable lines (accurate to 0.02 cm-1) are Ap = 4.96, 5.87, 6.76, 7.64, and 8.50 cm-1, (a) Calculate the C=S bond length in carbon disulfide. (Assume centrifugal distortion is negligible. The rotational Raman selection rule for linear molecules in 2 electronic states is AJ = 0, 2.) (b) Is this an R0 or Re value (c) Predict the shift for the 7 = 0—>2 transition. 

The 1H NMR spectra of the polymers were obtained with a Varian HR-300 spectrometer, at 110-120° C, using 5-10% solutions of polymer in hexachloro-butadiene. The effect of temperature and solvent on the H NMR spectrum of a cationically prepared poly(4-methyl-l-pentene) was investigated. Figure 1-3 show the results obtained with carbon disulfide, carbon tetrachloride, o-dichloro-benzene, p-dichlorobenzene, and hexachlorobutadiene. 

Fig. 1. 300MHzlHNMR spectrum of poly(4-methyl-l-pentene) in carbon disulfide and... 

Since two resonance lines at 39.0 and 47.7 ppm that correspond to those observed in the ttgg form and a resonance line at 49.0 ppm that corresponds to that in the tttt form are recognized in the gel spectrum, a coexistence of these two forms in the gel might be supposed. In an attempt to determine the possibility of the coexistence of the two forms in the gel, we measured the IR spectrum that is sensitive to the molecular conformation. The number of normal vibrational modes depends sensitively on the molecular conformation based on the selection rule of the symmetry species. Kobayashi et al. confirmed the vibrational modes assignable to the ttgg conformation in the IR spectrum for the gel from a sPP/carbon disulfide system [117]. However, since we used o-dichlorobenzene as solvent, we examined whether the gel structure depends on the solvent. 

The (1,1-diphenyl) phosphonitrile fluoride trimer is a colorless crystalline solid that melts at 68.5-69.5°C. It can be recrystallized from n-pentane, n-heptane, petroleum ether, or absolute methanol. It is also soluble in diethyl ether, carbon disulfide, and chloroform, but it is insoluble in and not attacked by water. The infrared spectrum shows a strong phosphorus-nitrogen stretching mode at 1250-1265 cm."1. Strong bands at 914-920, 900-906 cm."1 and at 812-820 cm."1 are associated, respectively, with phosphorus-fluorine asymmetric and symmetric stretching modes. 

Here, T is the observed line width (Av << F), 7d is the peak-to-valley intensity in the difference spectrum, and To is the peak height of the Raman line. Although this equation is for Lorentzian-shaped bands, the results are approximately the same for Gaussian-shaped bands (the constant 0.385 becomes 0.350). In the case of carbon disulfide-benzene mixtures, the smallest shift observed was -0.06 cm-1, and the associated error was 0.02 cm-1 (77). A convenient rotating system that can be used for (1) difference spectroscopy, (2) normal rotating sample techniques (solid and solution), and (3) automatic scanning of the depolarization ratios as a function of the wave number has been designed (45). 

Chlorohydridobis(tricyclohexylphosphine)nickel is a yellow-brown solid. It is thermally stable at ambient temperature but reacts with air. It is very soluble in benzene, tetrahydrofuran, and dichloromethane and is soluble in diethyl ether and petroleum ether. Carbon tetrachloride, carbon disulfide, and chloroform decompose the complex. The infrared spectrum shows a sharp v(Ni—H) band at 1916 cm-1 (KBr disk and Nujol mull). The high-field H nmr spectrum in benzene solution has a triplet (1 2 1) at t34.6 (TMS) with JpH 73.5 Hz. The splitting is caused by the coupling of the hydride proton with two equivalent 31P nuclei. This is consistent with a trans square-planar configuration. 

Sulfuryl chloride readily converted the zinc complex 84 to a yellow-orange solid 85 (Scheme 4) <1994IC4537 cf. CHEC-II(9)705>. The polymer 85 is transparent in the IR spectrum in the range 2500-3500 cm-1 demonstrating the absence of hydrocarbons. Upon treatment of the polymer 85 with carbon disulfide, the 1,2,5,6-tetraazocine 21 was isolated see (Section 14.09.3.2 1994IC4537). 

The S NMR spectrum of thiophene was initially studied as a solution in carbon disulfide <1970M1379> and its chemical shift relative to carbon disulfide was —220 - - 6 while those of 2- and 3-methylthiophene were -178-1-9 and — 197 + 26, respectively. The S chemical shift of neat thiophene (relative to aqueous cesium sulfate) was found to be —119ppm, while that of tetrahydrothiophene was —354ppm (Table 49) <1985J(F2)63>. 

Acid chloride—olefin addition and Friedel-Crafts cyclization A previous procedure was improved by use of methylene chloride as solvent rather than carbon disulfide. To check the progress of the reaction, one can quench a 2 3-ml. aliquot with water in a test tube, separate and dry the organic phase, and evaporate. The infrared spectrum will show disappearance of the acid chloride carbonyl band at 5.6(1 /j and appearance of the... 

They flash-photolyzed mixtures of NO2 and CS2, in concentration ratios of about 1 10 in an excess of Ar, at conditions under which no CS2 was photo-dissociated directly. With such excess of CS2, the O formed from the photolysis of NO2 reacted almost entirely with the carbon disulfide. The rate of reaction (22) was measured by monitoring the absorption spectrum of the CS formed. They obtained a value of 22 = 2.5 x 10 l.mole . sec at 305 °K, and found the activation energy of the reaction to be 0.6+0.3 kcal.mole . Smith has also reported the relative yield of CS and SO in various excited vibrational states. 

The IR spectra of phenazine and its derivatives have been studied in carbon disulfide solutions and as potassium bromide pellets. Because of the high symmetry of the phenazine ring, many of the fundamental vibrations are not visible in IR, but in Raman spectra. The complexity of Raman spectrum varies with the physical form of the sample. Characteristic IR absorption bands of phenazine occur at 3065, 1515, 1437, 1362, 1112, 1029, 958, 905, 820, 752, 745 cm. ... 

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