Carbon tetrachloride infrared spectrum

Fig. 5. Digital Spectrum Stripping of an Infrared Spectrum, a 0.05% butyl methacrylate in carbon tetrachloride b Residual spectrum after stripping that of carbon tetrachloride c Spectrum of pure butyl methacrylate in 0.1 mm path length cell for comparison. (Adapted from Ref. IJI)...

The OH stretching region of the infrared spectrum has been compared for dilute solutions of five heptanols in carbon tetrachloride the spectrum at 0.1 molarity and 25°C. gives a good indication of the association behavior of the alcohol. The picture for the two extreme types of behavior, as exemplified by 1-heptanol and pentamethylethanol, is shown in Figures 2 and 3. The three OH stretching bands occur in 1-heptanol at 3630,... 

Although no chemical reaction occurs, measurements of the freezing point and infra-red spectra show that nitric acid forms i i molecular complexes with acetic acid , ether and dioxan. In contrast, the infrared spectrum of nitric acid in chloroform and carbon tetrachloride - is very similar to that of nitric acid vapour, showing that in these cases a close association with the solvent does not occur. 

The purity of cyclobutanone was checked by gas chromatography on a 3.6-m. column containing 20% silicone SE 30 on chromosorb W at 65°. The infrared spectrum (neat) shows carbonyl absorption at 1779 cm. - the proton magnetic resonance spectrum (carbon tetrachloride) shows a multiplet at 8 2.00 and a triplet at S 3.05 in the ratio 1 2. 

The submitters report that this product solidifies when cooled and melts at 21-22 and that the product is stable when stored in a refrigerator. The product exhibits infrared absorption (carbon tetrachloride) attributable to C=0 stretching at 1810 and 1765 cm. and a proton magnetic resonance singlet at B 1.50 (carbon tetrachloride). The mass spectrum of the product exhibits the following relatively abundant fragment peaks m/e (relative intensity), 60(10), 59(99), 57(34), 56(86), 55(47), 50(21), 44(100), 43(30), 41(91), 40(27), and 39(61). 

The infrared spectra of alcohols change markedly with increasing concentration. For example, at very low concentration, the infrared spectrum of te/t-butyl alcohol in carbon tetrachloride contains a single sharp band at approximately 3600 cm corresponding to the OH stretching motion. As the alcohol s concentration increases (by adding more alcohol to the sample), a second broad OH stretch band grows in at approximately 3400 cm and eventually replaces the other band. 

In 1951, Witkop et al. interpreted the infrared spectra of quinol-2-and -4-ones to favor the oxo formulation. Since then, many investigators, especially Mason, have reported that potential a- and y-hydroxy compounds show infrared absorption bands in the vN—H (3500-3360 cm ) and vC—O (1780-1550 cm ) regions of the spectrum and, hence, exist predominantly in the oxo form references to this work appear in Table I. A study of the bands which occur in the NH-stretching region of the infrared spectra of a series of substituted pyrid-2-ones and quinol-2-ones also supported an oxo formulation for these compounds. Detailed band assignments have been published for pyrid-2- and -4-one. Mason has reported that solutions of j8-hydroxy compounds in chloroform or carbon tetrachloride show... 

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. 

Take 10 mL of commercial propan-2-ol and dilute to 100 mL with carbon tetrachloride in a graduated flask. Record the infrared spectrum and calculate the absorbance for the peak at 1718 cm-1. Obtain a value for the acetone concentration from the calibration graph. The true value for the acetone in the propan-2-ol will be 10 times the figure obtained from the graph (this allows for the dilution) and the percentage v/v value can be converted to a molar concentration (mol L-1) by dividing the percentage v/v by 7.326 e.g. 1.25 per cent v/v = 1.25/7.326 = 0.171 molL-1. 

Methylcarborane is an air-stable, white crystalline solid which is soluble in common organic solvents. The infrared spectrum (Nujol mull) contains major absorption bands at 3.90 (s), 8.83 (w), 9.12 (w), 9.69 (w), 9.83 (w), 10.03 (w), and 13.85 (s) p. The proton nuclear magnetic resonance spectrum of a carbon tetrachloride solution of methylcarborane contains a broad —CH resonance of intensity 1 at 6.52 r and a —CH3 resonance of intensity 3 at 8.02 r. 

The infrared spectrum (neat) shows major absorptions at 2970, 2920, 2855, 1660, 1450, 1375, 1380, 1255, 835, and 660 cm.-1 The proton magnetic resonance spectrum (carbon tetrachloride solution, tetra-methylsilane reference) has a four-line multiplet in the 1.55-1.85 p.p.m. region characteristic of the olefinic methyl protons, two peaks in the 2.0-2.2 p.p.m. region due to the four allylic methylene protons, a doublet at 4.02 p.p.m. (,J = 7.0 Hz.) due to the allylic methylene protons adjacent to the chlorine, a very broad triplet at 5.09 p.p.m.,... 

When a solution is tested, both analyte and solvent absorption bands will be present in the spectrum, and identification, if that is the purpose of the experiment, is hindered. Some solvents have rather simple IR spectra and are thus considered more desirable as solvents for qualitative analysis. Examples are carbon tetrachloride (CC14, only C-Cl bonds), choloroform (CHC13), and methylene chloride (CH2C12). The infrared spectra of carbon tetrachloride and methylene chloride are shown in Figure 8.21. There is a problem with toxicity with these solvents, however. For quantitative analysis, such absorption band interference is less of a problem because one needs only to have a single absorption band of the analyte isolated from the other bands. This one band can be the source of the data for the standard curve since the peak absorption increases with increasing concentration (see Section 8.11 and Experiment 25). See Workplace Scene 8.2. 

Normal glass will only transmit radiation between about 350 nm and 3 /rm and, as a result, its use is restricted to the visible and near infrared regions of the spectrum. Materials suitable for the ultraviolet region include quartz and fused silica (Figure 2.28). The choice of materials for use in the infrared region presents some problems and most are alkali metal halides or alkaline earth metal halides, which are soft and susceptible to attack by water, e.g. rock salt and potassium bromide. Samples are often dissolved in suitable organic solvents, e.g. carbon tetrachloride or carbon disulphide, but when this is not possible or convenient, a mixture of the solid sample with potassium bromide is prepared and pressed into a disc-shaped pellet which is placed in the light path. 

The infrared spectrum of y-crotonolactone shows two bands in the carbonyl r on at 5.60 and 5.71 fi in carbon tetrachloride (5%) [shifted to 5.61 and 5.71 fi in chloroform (5%)] and carbon-carbon stretching absorption at 6.23 fjt. The nuclear magnetic resonance spectrum shows olefinic peaks centered at 2.15r (pair of triplets) and 3.85r (pair of triplets), each due to one proton, and a two-proton triplet centered at 5.03t (in CCU). 

The checkers found n26d 1.4830 (lit.5 n26SD 1.4830) for the distillate. The n.m.r. spectrum3 shows two peaks at 1.41 (6H) and 2.00 p.p.m. (2H). No olefinic absorption was detectable. The infrared spectrum (carbon tetrachloride solution) shows three unusually well-resolved bands in the C-H stretching region at 3069, 2929, and 2852 cm.-1. 

The trapped product gave an immediate test with KI in acetic acid. Its infrared spectrum was similar to that of 3-butene-2-ol with major absorption peaks at 3, 8.7, 9.5, 10.3, and 10.8 microns and minor peaks at 6.3, 7.2, 7.7, 11.6, 12.4, and 12.6 microns. There was no absorption arising from carbonyl. In a 25% solution of hydroperoxide in carbon tetrachloride, the hydroperoxide proton gave rise to a broad band at 8.7 p.p.m. (referred to TMS) in the NMR spectra. 

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