Halomethanes . Hydrogen abstraction . Kinetic isotope effectIntroduction Chlorine atoms are important stratospheric species taking an active portion in ozone destruction cycles [1, 2]. The principle sources with the atmospheric chlorine atoms will be the photochemically labile chlorine compounds which include Cl2 and ClNO2 developed in some aqueous-phase reactions within the airborne seawater droplets. The gas-phase reactions of chlorine atoms using the hydrogen-containing atmospheric halocarbons cause the facile generation with the corresponding absolutely free radicals via hydrogen atom abstraction [1, 3]. Monofluoromethane may be the simplest of hydrofluorocarbons (HFCs), which are man-made organics predominantly utilized as protected replacements for ozone-depleting substances [1]. HFCs are chemically low reactive and have an ozone depleting prospective of zero as they include no chlorine. HFCs have long lifetimes within the atmosphere, and are only slowly removed by solar photolysis [4?].4-Bromo-7-(trifluoromethyl)quinoline Chemscene The primary impact of HFCs around the atmosphere is related with international warming.K. Brudnik : M. Twarda : D. Sarzyski : J. T. Jodkowski (*) Division of Physical Chemistry, Wroclaw Healthcare University, pl. Nankiera 1, 50-140 Wroclaw, Poland e-mail: [email protected] Mol Model (2013) 19:1489?Chloromethane (CH3Cl) would be the most abundant halocarbon in the atmosphere with an atmospheric lifetime of 17 months [7?]. Big organic sources of CH3Cl are biomass burning, oceanic emissions and vegetative emissions.161827-02-7 web The products on the atmospheric destruction of CH3Cl may be involved in a variety of catalytic atmospheric reaction cycles responsible for the depletion of the ozone layer [1]. The reaction with hydroxyl radicals is regarded as the dominant sink for atmospheric CH3Cl. Essentially the most crucial carrier of bromine towards the stratosphere is bromomethane (CH3Br) which can be produced by both anthropogenic and organic processes. CH3Br is a really efficient catalyst for ozone destruction. The atmospheric lifetime of CH3Br is estimated to become roughly two years [10]. The fate of atmospheric methyl bromide is mostly determined by degradation processes within the troposphere, specially by its reaction with OH radicals [1, 11].PMID:23329650 The hydrogen abstraction reactions of chlorine atoms with halomethanes, CH3X (exactly where X 0 F, Cl, Br) have already been the subjects of quite a few kinetic studies [12?4]. The key tropospheric sink for halogenated methanes which includes these three of interest in this study (CH3F, CH3Cl and CH3Br) is their reaction with OH radicals. The recent investigations recommend that concentrations of chlorine atoms within the marine boundary layer may very well be as a lot as one-tenth as high because the hydroxyl radical levels [1]. Considering that reactions of Cl atoms with several organics proceed significantly more rapidly than the corresponding OH reactions [12?4], it really is achievable that reactions with atomic chlorine may very well be a non-negligible sink for many hydrogencontaining atmospheric halomethanes. In this study we present a theoretical analysis on the mechanism and kinetics of the reactions of monosubstituted halogenated methanes CH3X with atomic chlorine: CH3 X ?Cl ! CH2 X ?HCl; ??enables the rate constant calculations for any bimolecular reaction proceeding through the formation of intermediate complexes. Benefits of those calculations provide structural and energetic details around the reaction pathways, which allow us to evaluate the price constants and their temperature dependence applying computational techniques of reaction rate theory. The calculated properties of t.