Quantitative Raman spectroscopic studies of nitronium ion concentrations in mixtures of sulphuric and nitric acids
1994; Elsevier BV; Volume: 326; Linguagem: Inglês
10.1016/0022-2860(94)85013-5
ISSN1872-8014
AutoresHowell G. M. Edwards, V. Fawcett,
Tópico(s)Spectroscopy and Laser Applications
ResumoThe intensity of the ν(NO) stretching band of NO+2 at Δν̄ = 1400 cm−1 in the Raman spectra of nitric acid—water—sulphuric acid mixtures has been studied to determine nitronium ion concentrations over the temperature range 293–313 K. The nitronium ion concentration in these mixtures was found to decrease with increase in temperature. The nitrating species for acid mixtures used in mono- and di-nitrations is consistent with nitronium ion, NO+2, but at a typical acid concentration of less than H2SO4:HNO3:H2O = 30:15:55 mole % used in industrial mononitrations, there is no spectroscopic evidence for the presence of NO+2. It is suggested that the nitrating species in these weaker acid solutions is he acid hydrate, H2NO+3, which is a weaker nitrating species than NO+2.
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