The Infra-Red Absorption Spectra of Organic Nitrates

The infra-red absorption of four organic nitrates has been studied in the region from 1.0 to 7.5μ. The liquids used are methyl nitrate, ethyl nitrate, propyl nitrate and butyl nitrate. Two absorption bands at 1.40μ and 2.96μ are attributed either to an OH linkage or water. All other bands are attributed to the carbon-hydrogen linkage and as an additional C${\mathrm{H}}_2$ group is introduced, two characteristics appear, namely, the intensity of all bands decreases and a shift of from 0.01 to 0.06μ to longer wave-length occurs. No characteristic absorption spectra of the N${\mathrm{O}}_3$ group have been found to exist in the organic nitrates. Previous workers have found that the carbon-hydrogen linkage gives regions of intense absorption at about 3.43, 6.86, 8 to 10 and 12 to 18μ. In the present work an intense band was observed at 6.7μ but the observations were not carried past 7.5μ and the other two fundamental frequencies were not observed. However, from observed bands there has been calculated four regions of intense absorption, which are assumed to be the fundamental frequencies and all other bands observed are attributed to a combination or overtones of these fundamentals.