Pemitrous acid

Alkylperoxy (RO2) and peroxyacyi (RC(O)OO) radicals react with NO to form NO2. The alkylperoxy radicals (RO2) react with NO2 to form pemitric acid-type compounds, which decompose thermally as the temperature increases. The peroxyacyi radical reacts with NO2 to form PAN-type compounds, which also decompose thermally. 

N2O5 is readily hydrated to nitric acid and reacts with H2O2 to give pemitric acid as a coproduct ... 

Permanent electrical multipole term Uq, lattice energies and, 1 176-177 Pemitrous acid, 22 147 Perovskites, ordered, 35 354, 370-371 Perovskite type fluorides, 20 152-166 Peroxides, see also specific compounds fluorinated, 16 109-168 fluoroaUcyl, spectral properties of, 16 154, 155... 

Mahoney, L. R. (1970). Evidence for the formation of hydroxyl radical in the isomerization of pemitrous acid to nitric acid in aqueous solution. J. Am. Chem. Soc. 92, 5262-5263. 

The experiments so far performed have sometimes been contradictory, but they have led to the conclusion that pemitrous acid does exist. 

It has been shown that aromatic hydrocarbons can be nitrated by pemitrous acid even at very low acid concentrations (e.g. 2%) at room temperature. The hydroxylation of the hydrocarbon takes place simultaneously in many cases. A characteristic feature of the reaction is that the nitro group mostly takes the meta position with respect to the substituent already present. If a nitro and a hydroxyl group are introduced simultaneously the hydroxyl group nearly always takes the ortho or para position with respect to the substituent already present. Diphenyl derivatives are also formed. 

The process would have to compete with the formation of pemitric acid, but since this compound redissociates, a certain share of HN02 would be produced nonetheless. Recent observations by Pitts et al. (1984c) have ascertained that HN02 is formed at night even in the absence of ozone (and N03), so that this process cannot explain the extent of nocturnal HN02 formation discussed above. 

Colorless crystals which decompose slowly at room temperature and are moderately stable only below 10°C. The melting point has not been determined. Subl. t. 34°C. According to R. Schwartz, NaOs reacts with H3O3 with the formation of pemitric acid N3O5 + H3O3 = HNO4 + HNO3. 

The explanation for this lack of correlation appears to lie in the factor governing the energies of the transition states. Reactions (4) and (13) are overall spin and symmetry allowed and their low rates must be attributed to the higher energies of their respective triplet and quartet transition states as compared with the doublet surfaces over which the other reactions can proceed. In the absence of Arrhenius parameters it carmot be excluded that reaction (10) proceeds non-adiabatically via a doublet surface. Reactions (8) and (9) must pass through intermediate states corresponding to pemitrous acid and chlorine nitrite both of which have been prepared by Knauth at Kiel they therefore go via attractive potential surfaces. 

Graham, R.A., Winer, A.M., Pitts Jr., J.N. Temperature dependence of the ununolecular decomposition of pemitric acid and its atmospheric implications. Chem. Phys. Lett. 51, 215-220 (1977)... 

Also obtained by nitration and hydroxylation of acetophenone with pemitrous acid (2%) [2077]. 

Raman data were used to determine the isotopic composition of oxygen during the isomerisation of pemitrous acid to nitrate in H20. The IR spectrum of the NO3 radical has been observed under high resolution. Ab initio calculations have been made of the vibrational wavenumbers of MXYs" and MXYs", where M = Li or Na, X = N or P, Y = O or S. ... 

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