Equilibria of nitric acid in sulfuric and perchloric acid at 25.degree.C by Raman and UV spectroscopy

Chemical and spectral behavior of nitric acid in aqueous sulfuric acid solutions: Absorption spectrum and molar absorption coefficient of nitronium ion

The chemical species formed from nitric acid in aqueous solutions of sulfuric acid (up to 18.0molL^-1) were studied by optical spectroscopy method. The concentration region of nitronium ion formation was identified and NO₂⁺ ion absorption spectrum was measured (λ_max≤190nm and ε₁₉₀=1040±50mol^-1Lcm^-1).

Kinetics study of heterogeneous continuous-flow nitration of trifluoromethoxybenzene

Trifluoromethoxybenzene (TFMB) nitration was studied in a microreactor, furnishing kinetic data that promoted the process development of large-scale synthesis.

Raman spectroscopic study of hydrogen bonding in benzenesulfonic acid/acrylonitrile solutions

Solutions of benzenesulfonic acid (BSA) in acrylonitrile in the range 1.02-6.53 mol dm(-3) were studied by FT-Raman spectroscopy. Spectra in the region of the acid SOH and benzenesulfonate anion SO3 stretching bands were analysed by band-fitting procedures in order to ascertain the degree of acid dissociation. This parameter changes from 0.42 (1.02 M solution) to 0.185 (6.53 M solution) despite the strong character of the acid. Interaction of acrylonitrile with undissociated BSA produces a new band in the nu(C[triple bond]N) Raman spectral region, displaced +21.4 cm(-1) and assigned to acrylonitrile molecules H-bonded to BSA. This displacement is in accord with the strong H-donor character of the acid. From the concentration of H-bonded acrylonitrile, the mean number of H-bonds in which each solvent molecule participates can be calculated. This number changes from ca. 0.2 in the less concentrated solution up to ca. 2.4 in the most concentrated solution. These results suggest that BSA-acrylonitrile complexes of fixed stoichiometry do not occur in the range of concentrations studied here.