21308-80-5Relevant academic research and scientific papers
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 (2001)
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.
Vacuum synthesis and determination of the ionization energies of different molecular orbitals for BrOBr and HOBr
Qiao, Zhimin,Sun, Shutao,Sun, Qiao,Zhao, Jincai,Wang, Dianxun
, p. 7111 - 7114 (2007/10/03)
HOBr, as a reservoir for bromine, is an important bromine species in the atmosphere, and BrOBr as a precursor of HOBr. However, far less is known about their properties in the gas phase, and no gas-phase photoelectron spectroscopy (PES) investigation is available to date. This paper discusses vacuum synthesis of pure BrOBr and HOBr, and determination of ionization energies of different molecular orbitals by the PES and both the GAUSSIAN 2 (G2) and the outer valence Green's functional (OVGF) calculations.
Low-temperature interaction between hydrogen bromide and ozone
Savilov,Yagodovskaya,Zosimov,Lunin
, p. 930 - 934 (2007/10/03)
The heterogeneous chemical reactions between ozone and HBr and a solution of between ozone and HBr adsorbed on the surface of ice were studied in the temperature range 77-223 K. The reagents interacted instantaneously with the formation of dark brown, golden yellow, and yellow-orange condensates. According to the low-temperature IR spectra, the reaction products were Br2O, Br2O3, BrO2, and Br2O4 bromine oxides. The initial product was Br2O, which afterward underwent successive oxidation. Ab initio quantum-chemical calculations were performed to determine the structures and relative stabilities of the specified bromine oxides.
Heterogeneous hydrolysis and reaction of BrONO2 and Br2O on pure ice and ice doped with HBr
Aguzzi, Arnaud,Rossi, Michel J.
, p. 5891 - 5901 (2007/10/03)
The rate of uptake of bromine nitrate (BrONO2) and dibromine monoxide (Br2O) on different types of ice, such as condensed (C), bulk (B), and single-crystal ice (SC) have been investigated in a Teflon-coated Knudsen flow reactor in the temperature range 180-210 K using mass spectrometric detection. For the whole temperature range the Br2O uptake kinetics is first order in [Br2O] with a mean initial uptake coefficient of γ0 = 0.24 ± 0.10, which leads to the exclusive formation of HOBr. The BrONO2 hydrolysis has been measured on B-,C-, and SC-type ice and leads to HOBr and Br2O on all types of ice. At a fixed temperature the rate law is first order in [BrONO2] with γ ≈ 0.3 at 180 K. The observed negative temperature dependence for the heterogeneous hydrolysis of BrONO2 on pure ice leads to Ea of -2.0 ± 0.2, -2.1 ± 0.2, and -6.6 ± 0.3 kcal/mol on C-, B- and SC-type ice, respectively. Despite the high reactivity of BrONO2 on ice substrates, the kinetics of interaction of BrONO2 on ice nevertheless depends on the type of ice used. No saturation of the uptake coefficient has been observed during the BrONO2 hydrolysis on ice in contrast to the ClONO2/ice system. On ice samples doped with approximately 5 × 1016 molecules HBr per cm3 the kinetics of the interaction of BrONO2 with HBr leads to an uptake coefficient similar to that for BrONO2 hydrolysis. The interaction of BrONO2 with HBr occurs via the hydrolysis of BrONO2 to HNO3 and HOBr where the latter reacts with HBr in a fast secondary reaction to produce Br2 with Ea = -1.2 ± 0.2 kcal/mol.
Dibromine monoxide, Br2O, and bromine dioxide, OBrO: Spectroscopic properties, molecular structures, and harmonic force fields
Muller,Miller,Cohen
, p. 2129 - 2131 (2008/10/09)
Two bromine oxides with more than two atoms have been structurally characterized for the first time in the gas phase. Both molecules occur over a solid product formed in the reaction of O and Br2. Under certain conditions BrO, OBrO, and Br2O were obtained simultaneously.
