Hydrogen chloride spectrum

Figure 4. Arc length of Figure 3C as a function of the amount of the hydrogen chloride spectrum. Figure 3D, that has been subtracted...

Figure 5. Lower curve amount of hydrogen chloride spectrum subtracted to minimize the arc length vs. the spectral offset in cm between the two spectra shown in Figures 3C and 3D. Upper trace achieved minimal arc length vs.offset.

In the latter case the structure was established by reduction with stannous chloride in acetic acid, which afforded the imidazole derivative (104), thus proving ortho substitution, followed by comparison of the ultraviolet spectrum of 104 with the two possible benzimidazole derivatives of carbazole. Deamination of 103 via diazotization in sulfuric acid afforded 1-nitrodibenzothiophene (105) (54%), being the only recorded route to this compound (Scheme 5). Initial attempts to hydrolyze 102 to the nitroamine (103) had been made with ethanolic hydrogen chloride... 

Figure 3. Absorbance spectrum of ambient laboratory air at different scale pensions together with a reference spectrum of hydrogen chloride (D)...

Carbo-phosphorins are relatively basic. They are protonated by aqueous hydrogen chloride, thereby losing their color. According to Markl, the UV spectrum of the salt is similar to that of 1,2-dihydro-X -phosphorins (Fig. 25). However, it cannot be concluded on the basis of the UV spectrum alone that protonation takes place at position C—2. The C-4 position can also be protonated, as has been shown by NMR spectroscopy to be the case for 1, l-dimethoxy-2.4.6-triphenyl-X -phos-phorin. The influence of acid addition on the UV spectra is similar in both classes of compounds (compare Fig. 25 with Fig. 26). However, it should be noted that aqueous acids cannot be used to protonate l,l-dimethoxy-2.4.6-triphenyl-X -phos-... 

Spectrum.—According to J. Tyndall,18 hydrogen chloride and hydrogen bromide absorb heat rays. W. H. Julius found that hydrogen chloride had an absorption band for the wave-length 3 68[i and K. Angstrom and W. Palmaer at 3 41/u,. W. de W. Abney and E. R. Festing found liquid hydrochloric acid had very feeble absorption lines in the ultra-red at 732, 741, 845, 867, and 949/u/i. 

With these compounds the presence of the halogen will have been detected in the tests for elements. Most acid halides undergo ready hydrolysis with water to give an acidic solution and the halide ion produced may be detected and confirmed with silver nitrate solution. The characteristic carbonyl adsorption at about 1800 cm -1 in the infrared spectrum will be apparent. Acid chlorides may be converted into esters as a confirmatory test to 1 ml of absolute ethanol in a dry test tube add 1 ml of the acid chloride dropwise (use a dropper pipette keep the mixture cool and note whether any hydrogen chloride gas is evolved). Pour into 2 ml of saturated salt solution and observe the formation of an upper layer of ester note the odour of the ester. Acid chlorides are normally characterised by direct conversion into carboxylic acid derivatives (e.g. substituted amides) or into the carboxylic acid if the latter is a solid (see Section 9.6.16, p. 1265). 

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