Rates and activation energies of nitronium ion formation and reaction in the nitration of toluene in ∼78% sulphuric acid
Keyword(s):
A stopped-flow spectrometer has been used to investigate the mechanism of the nitration of toluene, and to determine kinetic parameters for the formation and reaction of nitronium ion, in 77.3 and 78.45 wt.% sulphuric acid. The protonation of nitric acid to form nitronium ion and water is found to occur at similar rates at both acid concentrations and to have an activation energy of 18.3 ± 4.0 kcal mol−1. The activation energy of the reverse reaction, the heat of the reaction, and the activation energy of encounter complex formation between nitronium ion and toluene are estimated to be respectively 10.5 ± 4.0, 7.8 ± 0.5, and 5.9 ± 0.1 kcal mol−1 in 77.3% H2SO4 and 12.0 ± 4.0, 6.3 ± 0.5, and 6.0 ± 0.1 kcal mol−1 in 78.45% H2SO4.
1972 ◽
pp. 127
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2012 ◽
Vol 13
(4)
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