13444-87-6Relevant articles and documents
Temperature-dependent rate coefficients for the reactions of Br(2P3/2), Cl(2P3/2), and O(3PJ) with BrONO2
Soller,Nicovich,Wine
, p. 1416 - 1422 (2007/10/03)
A laser flash photolysis-resonance fluorescence technique has been employed to investigate the kinetics of reactions of the important stratospheric species bromine nitrate (BrONO2) with ground-state atomic bromine (k1), chlorine (k2), and oxygen (k3) as a function of temperature (224-352 K) and pressure (16-250 Torr of N2). The rate coefficients for all three reactions are found to be independent of pressure and to increase with decreasing temperature. The following Arrhenius expressions adequately describe the observed temperature dependencies (units are 10-11 cm3molecule-1s-1): k1 = 1.78 exp(365/T), k2 = 6.28 exp(215/T), and k3 = 1.91 exp(215/T). The accuracy of reported rate coefficients is estimated to be 15-25% depending on the magnitude of the rate coefficient and on the temperature. Reaction with atomic oxygen is an important stratospheric loss process for bromine nitrate at altitudes above approximately 25 km; this reaction should be included in models of stratospheric chemistry if bromine partitioning is to be correctly simulated in the 25-35 km altitude regime.
The Synthesis of 15N- and 18O-Isotopically-Enriched Nitryl Bromide, IR Matrix Spectra, and Force Fields of BrNO2, cis-BrONO, and trans-BrONO
Scheffler, Dieter,Willner, Helge
, p. 4500 - 4506 (2008/10/08)
The gas phase reaction between BrNO and O3 at low pressure (2 in about 60% yield. In this manner 15N- and 18O-labeled BrNO2 are prepared. In addition, it is shown that BrNO2 also forms by the heterogeneous low-temperature reaction between gaseous BrNO and solid sulfuric acid, doped with H2O2. It can be assumed that BrNO2 may be formed in a similar way under stratospheric conditions. The isotope scrambling in the reaction between BrNO and 18O3 as well as in the gas phase equilibrium BrNO + NO2 ? BrNO2 + NO are investigated. For the equilibrium constant a lower limit of K298 ≥ 1 × 10-3 is deduced from infrared measurements. A detailed IR and Raman study on BrNO2 is performed. Photolysis of matrix-isolated BrNO2 at different wavelengths leads to a mixture of cis- and trans-BrONO. The vibrational data of BrNO2 (6 fundamentals, 7 combinations), cis-BrONO (5 fundamentals, 1 overtone), and trans-BrONO (4 fundamentals, 8 combinations) as well as the calculated force fields are in excellent agreement with the ab initio values, predicted by T. J. Lee (J. Phys. Chem. 1996, 100, 19847).
