Spectra of nitric esters

A few ultra-violet spectra of nitric esters were also given by Dalmon and Beilin [9]. 

As early as 1929 Plyler and Steele [10] began an investigation of the infra-red spectra of nitric esters in the range methyl to n-butyl nitrates. Dadieu, Jele and Kohlrausch [11] studied the Raman spectra of nitric esters as well as inorganic nitrates, and aliphatic and aromatic nitro compounds. 

The Raman spectra of nitric esters have received relatively less attention for two reasons ... 

Kumler [23], McCallum and Emmons [24] examined the infra-red spectra of nitric esters of hydroxyacids. 

However there exists no evidence for this. Moreover, investigation of the absorption spectra of nitric acid, nitrous acid and aliphatic nitro compounds indicates that the peroxide structure hypothesis is incorrect, because nitric acid esters behave as compounds having the normal ester structure (II) (Crigee and Schnorrenberg [la], Matsushima [lb]) ... 

X-Ray investigations, electron diffraction, Raman and infra-red spectra, and dipole moment measurements of nitric esters also support the idea of a symmetrical structure for the nitrate group (in spite of certain discrepancies obtained by different authors) ... 

The O-nitro group (the nitroxy group) gives an absorption band of about 270 va.fi, in the ultra-violet region, i.e. a band similar to that of the C-nitro group. A relatively small amount of work has been done on the ultra-violet absorption spectra of nitric acid esters but it has been established that in esters containing no other chromophoric groups absorption is extremely low (e = 10-20) even lower than in case of aliphatic nitro compounds. 

Hantzsch opposed the theory of N205 existing in the nitrating mixture HN03 + + H2S04 Due to the importance of the Hantzsch theory in the development of our views on the nature of the nitration process, we shall discuss it in detail. In a number of works Hantzsch [21-23] developed a theory based on Schafer s experiments [24] on the absorption spectrum in ultra-violet light. Schafer s chief observation was, that the spectrum of anhydrous nitric acid in a non-aqueous solvent (hexane, sulphuric acid, etc.) is analogous with the spectra of nitric acid esters,... 

Solutions, of nitric acid have three different ultraviolet-absorption spectra. In dilute aqueous solution, its spfectnim is that of the nitrate ion, NOa . In an inert weakly polar solvent such as chloroform, its spectrum is the same as that of ethyl nitrate, indicating that the nitric acid exists as unionized HNO3. A third spectrum is characteristic of sulfuric acid solutions of nitric acid and its esters, indicating that here nitric acid does not exist as the nitrate ion or as unionized nitric acid. The Haman spec-... 

The infrared spectra (benzene solution) of the isohexide nitrates, as well as of their mixed nitric and p-toluenesulfonic esters, are well established. The positions of the v and the bands for the nitrato group are remarkably constant, at 1645 3 cm-1 and 1282 1 -1 (endo), and 1274 1 cm-1... 

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