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  • Thermodynamic nitration rates of aromatic compounds: Part 4: Temperature dependence in sulphuric acid of HNO(3)-NO(3)(+) equilibrium, nitration rates and acid properties of the solvent


The protonation-dehydration equilibrium of nitric acid (HNO(3)+H(+) = H(2)O+NO(2)(+)) has been studied in the range 80% to 94% weight H(2)SO(4) as a function of temperature, and the variation in the ratio of NO(2)(+) to HNO(3) has been analyzed to evaluate the dissociation constants and the enthalpy of dissociation of the process. The nitration rates of some aromatic compounds, related both to the stoichiometric concentration of nitric acid and to the effective concentration of electrophilic species have been investigated in the range 50% to 100% weight H(2)SO(4) and the dependence upon acidity and temperature of the different rate profiles is discussed. Equilibria and nitration rates in sulphuric acid have been analyzed using the Mc activity coefficient functions whose values have been estimated over a range of temperature between 25 C and 90 C. The general trend observed in the acidic properties of the medium is reported. It is shown that the temperature has a small influence on the Mc function.

Additional information

Authors: MARZIANO N C, University of Venice, Chemistry Department (IT);TOMASIN A, University of Venice, Chemistry Department (IT);TORTATO C, University of Venice, Chemistry Department (IT);ZALDIVAR J M, JRC Ispra (IT)
Bibliographic Reference: Article: Journal of the Chemical Society, Perkin Transactions II (1998)
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