https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12135 Wed 11 Apr 2018 10:34:30 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21380 2. A simplified rate law based on the known elementary reaction mechanism provides an excellent fit to the experimental data. The rate constant, 1.34 × 10^–6 M^–1 s^–1, is thought to be of higher accuracy than those in the literature as it does not depend on the rate of parallel reaction pathways or on the rate of interphase mass transfer of gaseous reaction products. The activation energy for the simplified rate law was established to be 107 kJ mol^–1. Quantum chemistry calculations indicate that the majority of the large activation energy results from the endothermic nature of the equilibrium 2HNO₂ ⇄ NO + NO₂ + H₂O. The rate constant for the reaction between nitrate ions and nitrous acid, which inhibits HNO₂ decomposition, was also determined.]]> Sat 24 Mar 2018 08:04:59 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27420 eq corresponds to 559-382 M(⁻²) for thioacetamide (TA, 15-25 °C) and 12600-5590 M(⁻²) for thiourea (TU, 15-35 °C), whereas the reaction enthalpies amount to -27.10 ± 0.05 kJ for TA and -29.30 ± 0.05 kJ for TU. Theoretical calculations via a thermochemical cycle agree well with reaction free energies from experiments, with errors of -2-4 kJ using solvation method SMD in conjunction with hybrid meta exchange-correlation functional M05-2X and high-accuracy multistep method CBS-QB3 for gas-phase calculations. The kinetic rates increase with acidity at activation energies of 54.9 (TA) and 66.1 kJ·mol(-1) (TU) for the same temperature range, confirming activation-controlled reactions. At pH 1 and below, the main decomposition pathway for the S-nitroso species leads to formation of nitric oxide.]]> Sat 24 Mar 2018 07:35:23 AEDT ]]>