Study of the reactions of OH with HCl, HBr, and HI between 298 K and 460 K.

The reactions between OH radicals and hydrogen halides (HCl, HBr, HI) have been studied between 298 and 460 K by using a discharge flow-electron paramagnetic resonance technique. The rate constants were found to be (298 K) = (7.9 ± 1.

Atmospheric Lifetimes of Halogenated Hydrocarbons: Improved Estimations from an Analysis of Modeling Results.

Detailed results of computer modeling of halocarbon removal rates from the atmosphere are analyzed to find simple correlations useful for improving estimations of the atmospheric lifetimes of industrial chemicals based on the rate constants for their reactions with OH and O(D) and their UV absorption spectra. Ths analysis is limited to relatively long-lived chemicals that are well mixed in the troposphere.

Deriving Global OH Abundance and Atmospheric Lifetimes for Long-Lived Gases: A Search for CHCCl Alternatives.

An accurate estimate of global hydroxyl radical (OH) abundance is important for projections of air quality, climate, and stratospheric ozone recovery. As the atmospheric mixing ratios of methyl chloroform (CHCCl) (MCF), the commonly used OH reference gas, approaches zero, it is important to find alternative approaches to infer atmospheric OH abundance and variability. The lack of global bottom-up emission inventories is the primary obstacle in choosing a MCF alternative.

Photochemical Properties of CH═CH-CFCl-CFBr (4-Bromo-3-chloro-3,4,4-trifluoro-1-butene) and CH-O-CH(CF) (Methyl Hexafluoroisopropyl Ether): OH Reaction Rate Constants and UV and IR Absorption Spectra.

Rate constants for the reactions of hydroxyl radicals (OH) with 1,1,1,3,3,3-hexafluoroisopropyl methyl ether (CH-O-CH(CF)) and 4-bromo-3-chloro-3,4,4-trifluoro-1-butene (CH═CH-CFCl-CFBr) have been measured over the temperature range 230-370 K to give the following Arrhenius expressions: k(T) = 7.69 × 10 × (T/298) × exp(+342/T), cm molecule s, and k(T) = (6.45 ± 0.

Photochemical properties of hydrofluoroethers CH3OCHF2, CH3OCF3, and CHF2OCH2CF3: reactivity toward OH, IR absorption cross sections, atmospheric lifetimes, and global warming potentials.

Rate constants for the gas phase reactions of OH radicals with three partially fluorinated ethers, CH3OCF3 (kHFE-143a), CH3OCHF2 (kHFE-152a), and CHF2OCH2CF3 (kHFE-245fa2), were measured using a discharge flow-electron paramagnetic resonance technique over the temperature range 298-460 K. The temperature dependences of the rate constants can be represented by the following expressions: kHFE-143a(T) = (1.10 ± 0.