Ethanol infrared absorptions

The ethanolic filtrate can be concentrated to 10-15 ml. imder reduced pressure to obtain 0.3 g. (7%) of crude product, m.p. 187-202°. Unchanged starting material, if present, is concentrated in this second fraction and may be detected by the furan resonance at 8 5.86 in the proton magnetic resonance spectrum or by a sharp infrared absorption... 

Dipropyl ketoxime (heptan-4-one oxime). Heat a mixture of 20 g (0.18 mol) of heptan-4-one, 17 g (0.25 mol) of hydroxylamine hydrochloride, 19.6 g (20 ml, 0.25 mol) of pyridine and 150 ml of ethanol under reflux for 1 hour in a 500-ml round-bottomed flask. Rearrange the condenser for downward distillation and remove the ethanol on the water bath. Allow the residue in the flask to cool and add 150 ml of water. Extract the oxime with three 50 ml portions of ether. Wash the combined extracts with water and dry over magnesium sulphate. Remove the ether on the rotary evaporator and distil the residue at atmospheric pressure. Collect the fraction having b.p. 192-195 °C the yield is 18.2g (80%). The oxime shows infrared absorptions at 3300 cm-1 (O—H stretch) and 1655 cm-1 (C=N stretch). 

The solvent used in the determination of rotations appears in parentheses. Key to solvents (a) acetone (c) chloroform (d) dioxane (de) 95% ethanol (e) ethanol (m) methanol (mC) methyl Cellosolve (n) 8% sodium hydroxide (Nn) N sodium hydroxide (p) pyridine (s) 1% sulfuric acid (w) water. The temperature range is from 13 to 31°. b References 278 to 308 appear in a separate list starting on page 380. Italicized references are for infrared absorption spectra all others refer to ultraviolet absorption spectra. 

Test A The infrared absorption spectrum is concordant with the reference spectrum of mefenamic acid or with the spectrum obtained from mefenamic acid reference standard. If the spectra are not concordant, dissolve a sufficient quantity of the substances in the minimum volume of ethanol (95%), evaporate to dryness, and prepare new spectra of the residues. 

Bromobis[2,3-butanedione dioximato( 1 -)] (4-terf-butylpyridine)cobalt(lIl) is a tan, microcrystalline solid with greatly enhanced solubility in organic solvents compared to the chloro(pyridine) analogue. It is also the compound of choice in preparing alkylcobaloximes by the subsequent procedure because of the ease of isolation of the resultant products. In addition, the bromo(4-ferf-bupy) species react directly with electron-rich olefins, such as ethyl vinyl ether, in the presence of ethanol to yield, in this case, bis[2,3-butanedione dioximato(l-)]-(2,2-diethoxyethyl)(pyridine)cobalt(III).1J Conversion of the dimethyl sulfide compound to the pyridine derivatives is readily detected by a characteristic infrared absorption at 1600 cm 1 (pyridine stretch). The H nmr spectrum of bromobis[2,3-butanedione dioximato(1 -)] (4-ferf-butylpyridine)cobalt (III) has absorptions in the alkane region in the ratio of 3 4 at 6 1.25 ppm [Py—C (CH3)3 ] and 6 2.43 ppm (dh—CH3) from tetramethylsilane. 

Fig. 32. Infrared absorption spectrum of ethanol in CC14 with the association band (3300 cm-1, broad) and the band of the free OH groups (about 2900 cm-1, double symmetric and antisymmetric vibration) and with the GH band (3500 cm-1).

O-protonation of 5,5-dimethyI-3-(N-pyrrolidyl)-2-cyclohexene-l-one [246], based on the infrared spectrum of its perchlorate (Leonard and Adamcik, 1959), was confirmed by ultraviolet spectra (Alt and Speziale, 1965). The protonation of the bicyclic system [247], which is certainly N-protonated owing to steric hindrance to meso-merism, leads to a cation with a maximum absorption at 212 nm (in ethanolic hydrochloric acid) and three strong infrared absorptions in the solid hydrochloride at 1655 cm-1 and 1720 cm 1 for the double bonds and at 2430 cm 1 for the NH-vibrations (Dolby et al., 1971). 

The association constant of pyridazine with ethanol was found to be 4.9 (from electronic absorption spectra) and 6.8 (infrared absorption spectra), and the corresponding values for the strength of the hydrogen bond are 4.2 and 4.6 kcal. The hydrogen-bonded form of P3n-idazine was considered to comprise one alcohol at one azine-nitrogen at small mole ratios of alcohol to azine and to involve the second nitrogen at high mole ratios (an additional shift in the electronic spectrum. The association constants (3.1-3.8) of pyridine, quinoline, and isoquinoline with methanol in carbon tetrachloride have been determined by infrared spectroscopy. 

Bis(4-imino-2-pentanonato)copper(II) is obtained as short dark gray, almost black, needles from 95% ethanol. The compound melts with decomposition at 190 to 192°. Prominent bands in the infrared absorption spectrum of the compound have been listed and discussed. ... 

FIGURE 20.10 The infrared absorption spectrum of ethanol, CH3CH2OH. Each peak is labeled with the vibrational motion from which it arises. 

These copper(II) ternary complexes are generally green-blue solids, stable in air, and fairly soluble in water, methanol, and ethanol. Furthermore, those with dicarboxylates and amino acid residues exhibit a characteristic, strong infrared absorption band around 1600 cm"1 due to the coordinated carboxylate group. The infrared spectra from 4000-200 cm 1 as well as the electronic spectra of these complexes have been recorded and assignments made.5 6... 

This alkaloid is a crystalline solid, m.p. 89 , [a] —56.75° (ethanol) that was first assigned the empirical formula C17HJ4O2N (83), which was later corrected to C14H21ON (87). It forms a hydrochloride, m.p. 205°. The infrared absorption spectrum of the base and that of one of the forms of the diastereoisomer of l-methyl-2-(j8-hydroxy- 8-pheny-lethyl)-piperidine, prepared from phenyl-(a-pyridyl)-acetylene, were identical (88). 

Crystals, mp 109°. bp7Wj 238s, Sublimes at 13 mm and 90 to 100. Infrared absorption (solid) 7.6-8, m Dipole mo-ment 4,44 (vapor)- Freely sol in water, methanol ethanol, acetone Sparingly sol in ether. 

Crystals from abs ethanol a- and 0-dtastereoisovner, separated by fractional crystn, have different crystal forms and different infrared absorption spectra. LDg, in female, male ratsfmg/kg) 3399 624, 3576 954 (Goldenthal). 

A soln. of ci s,frans,fruns-1,5,9-cyclododecatriene in ethanol treated with excess (10 moles) hydrazine hydrate in the presence of a catalytic amount of cupric sulfate with vigorous bubbling of air and stirring until the infrared absorption of the trans-double bonds has disappeared, whereby the hydrogenation is performed by the diimide generated in situ cis-cyclododecene. Y 82% purity 95%. M. Ohno and M. Okamoto, Tetrah. Let. 1964, 2423. 

Infrared spectroscopic data (28) for solid A-o-tolyl- and iV-jS-naphthyl-D-glucosylamine shows peaks at 6.05 /x- Such peaks are usually due to a —C=N— grouping, indicative of a Schiff base. The compounds p-tolyl-and p-nitrophenyl-D-glucosylamine, however, do not show such a peak. In the reaction between 2,3,4,5-tetra-0-acetyl-aZde%do-D-ribose and aniline in ethanol or methanol, crystalline compounds corresponding to the Schiff base type (V) were isolated these contained one molecule of ethanol or methanol. The infrared absorption spectra of these compounds, however, showed that they did not have the Schiff base structure (V), but were of... 

Figure 12.12 An infrared absorption spectrum of ethanol, CH3CH2OH. A transmittance of 100% means that all the energy Is passing through the sample, whereas a lower transmittance means that some energy is being absorbed. Thus, each downward spike corresponds to an energy absorption.

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