Chlorine atom initiated reactions of selected tropospheric halocarbons — Kinetic and product studies

2006 ◽  
Vol 84 (12) ◽  
pp. 1686-1695 ◽  
Author(s):  
Anisha Garib ◽  
Qadir K Timerghazin ◽  
Parisa A Ariya
Keyword(s):  
Gas Chromatography ◽  
Chlorine Atom ◽  
Rate Constants ◽  
Room Temperature ◽  
Marine Boundary Layer ◽  
Relative Rate ◽  
Addition Product ◽  
Chlorinated Ethenes ◽  
Oxidation Reactions ◽  
Chlorine Atoms

Halogens are suggested as important atmospheric oxidants in the marine boundary layer. The room-temperature kinetics of the chlorine-initiated reactions of three biogenic brominated hydrocarbons and four anthropogenic chlorinated ethenes was investigated by gas chromatography with flame ionization detection (GC–FID) at a pressure of 1 atm (1 atm = 101.325 kPa) in air, using the relative rate technique. The rate constants (× 1013 cm3 molecule–1 s–1) for CH2Br2, CHBr2Cl, and CHBr3 reactions at 298 ± 2 K were found to be 4.25 ± 0.65, 2.03 ± 0.31, and 2.81 ± 0.41, respectively, using methane as a reference compound. Room temperature rate constants (±1011 cm3 molecule–1 s–1) obtained for 1,1-dichloroethene, cis-dichloroethene, trans-dichloroethene, and trichloroethene using ethene as a reference are 13.4 ± 3.3, 9.1 ± 2.3, 7.4 ± 1.8, and 7.7 ± 1.9, respectively. The rate constants of chlorine-atom reactions with various hydrocarbons obtained in this work and taken from literature were correlated with corresponding rate constants of the OH radical available in the literature. The temperature dependences for the reactions of chlorine atoms with chlorinated ethenes were studied within the 298–358 K range. The corresponding Arrhenius expressions for the rate constants are (cm3 molecule–1 s–1): ln k = (–25.26 ± 0.17) – (758 ± 55)/T for 1,1-dichloroethene, ln k = (–25.79 ± 0.10) – (799 ± 34)/T for cis-dichloroethene, ln k = (–26.74 ± 0.09) – (1018 ± 28)/T for trans-dichloroethene, and ln k = (–26.10 ± 0.26) – (846 ± 83)/T for trichloroethene. In addition, product studies for the chlorine-initiated gas phase oxidation reactions of CHBr3 and CHBr2Cl were performed using gas chromatography with mass spectrometric detection (GC–MS). The only identified product for the reaction of CHBr3 with Cl reaction was COBr2, while for the CHBr2Cl + Cl reaction, COBrCl and COCl2 were observed, indicating the possibility of halogen atom release. The atmospheric implications of the results obtained are discussed.Key words: tropospheric reactions, kinetics, chlorine atoms, chlorinated hydrocarbons, brominated hydrocarbons.

REACTION OF OXYGEN ATOMS WITH BUTADIENE

1960 ◽  
Vol 38 (11) ◽  
pp. 2187-2195 ◽  
Author(s):  
R. J. Cvetanović ◽  
L. C. Doyle
Keyword(s):  
Pressure Dependence ◽  
Rate Constants ◽  
Room Temperature ◽  
Relative Rate ◽  
Excess Energy ◽  
General Mechanism ◽  
Arrhenius Parameters ◽  
Heats Of Reaction ◽  
Relative Rate Constants ◽  
Oxygen Atoms

Reaction of oxygen atoms with 1,3-butadiene has been investigated at room temperature. It is found that it conforms to the general mechanism established previously for the analogous reactions of monoolefins. Only 1,2-addition occurs, and the addition products, butadiene monoxide and 3-butenal, possess excess energy when formed as a result of high heats of reaction. The pressure dependence of the formation of the addition products yields the values of the "lifetimes" of the initially produced "hot" molecules. The relative rate constants have been determined at 25 and 127 °C and from these the relative values of the Arrhenius parameters have been calculated.

Gas-phase kinetic and mechanism study of the reactions of O3, OH, Cl and NO3 with unsaturated acetates

2018 ◽  
Vol 15 (7) ◽  
pp. 411
Author(s):  
Shuyan Wang ◽  
Lin Du ◽  
Narcisse T. Tsona ◽  
Wenxing Wang
Keyword(s):  
Gas Chromatography ◽  
Rate Constants ◽  
Relative Rate ◽  
Anthropogenic Sources ◽  
Gas Chromatography Mass Spectrometry ◽  
Mechanistic Study ◽  
Mechanism Study ◽  
Mechanistic Investigation ◽  
Chemical Behaviour ◽  
Flame Ionisation

Environmental contextAcetate esters, emitted into the atmosphere from both natural and anthropogenic sources, can participate in photochemical processes leading to the formation of secondary organic aerosols. We report a study on the kinetics and mechanisms of the reaction of two acetate esters with O3, OH, NO3, and Cl radicals. The results help our understanding of the chemical behaviour of this important class of compounds in the atmosphere. AbstractThe photodegradation reactions of isopropenyl acetate (IPA) and 2-methyl-2-propenyl acetate (MPA) initiated by O3, OH, Cl and NO3 radicals have been investigated in a 100 L Teflon reactor at 293 ± 3 K, by using gas chromatography with flame-ionisation detection as well as thermal desorption–gas chromatography–mass spectrometry to monitor the reactants and the products. The rate constants for the reactions of IPA and MPA with the four atmospheric oxidants were determined by using either absolute or relative rate methods. The following rate constants (in units of cm3 molecule−1 s−1) were obtained: k(O3 + IPA) = (0.37 ± 0.06) × 10−18, k(OH + IPA) = (6.44 ± 0.74) × 10−11, k(Cl+ IPA) = (4.33 ± 0.52) × 10−10, k(NO3 + IPA) = (1.62 ± 0.22) × 10−14, k(O3 + MPA) = (2.76 ± 0.40) × 10−18, k(OH + MPA) = (7.41 ± 0.92) × 10−11, k(Cl + MPA) = (3.33 ± 0.39) × 10−10, k(NO3 + MPA) = (1.34 ± 0.23) × 10−14. With the exception of the kinetic study of the reactions of O3 and OH with IPA and the mechanistic study of the reaction of IPA with O3, the current research reports the first kinetic and mechanistic investigation for these reactions at atmospheric pressure. Acetic anhydride and 1-acetoxyacetone are the main products of the reactions of IPA and MPA, respectively. On the basis of the products and estimated tropospheric lifetimes of the two esters, reaction mechanisms are proposed and the atmospheric implications are discussed.

Rate Constants for the Reactions of Chlorine Atoms with Some Simple Alkanes at 298 K: Measurement of a Self-Consistent Set Using Both Absolute and Relative Rate Methods

1995 ◽  
Vol 99 (35) ◽  
pp. 13156-13162 ◽  
Author(s):  
Peter Beichert ◽  
Lisa Wingen ◽  
Jason Lee ◽  
Rainer Vogt ◽  
Michael J. Ezell ◽  
...  
Keyword(s):  
Rate Constants ◽  
Relative Rate ◽  
Chlorine Atoms ◽  
Self Consistent

Kinetic investigations of chlorine atom initiated photo oxidation reactions of 2,3-dimethyl-1,3-butadiene in the gas phase: an experimental and theoretical study

RSC Advances ◽  
2016 ◽  
Vol 6 (72) ◽  
pp. 67739-67750 ◽  
Author(s):  
S. Vijayakumar ◽  
B. Rajakumar
Keyword(s):  
Experimental Method ◽  
Gas Phase ◽  
Chlorine Atom ◽  
Theoretical Study ◽  
Relative Rate ◽  
Rate Coefficients ◽  
Oxidation Reactions ◽  
Photo Oxidation ◽  
P Rate ◽  
Kinetic Investigations

Rate coefficients for the reaction of chlorine atoms with 2,3-dimethyl-1,3-butadiene were measured over the temperature range of 269–393 K by using a relative rate experimental method with reference to isoprene and 1-pentene.

The relative rate constants of oxygen, O(3P), atoms with different gaseous unsaturated compounds at room temperature

1986 ◽  
Vol 64 (9) ◽  
pp. 1925-1929 ◽  
Author(s):  
H. Deslauriers ◽  
G. J. Collin
Keyword(s):  
Double Bond ◽  
Rate Constants ◽  
Room Temperature ◽  
Relative Rate ◽  
Unsaturated Hydrocarbon ◽  
Ionization Potentials ◽  
Total Rate ◽  
Simple Method ◽  
Unsaturated Compounds ◽  
Relative Rate Constants

A simple method is proposed in order to measure the relative rate constants of the interactions between oxygen O(3P) atoms and unsaturated hydrocarbon. A 147 nm photolysis of air is used to produce the O(3P) atoms. In the presence of 1,2-butadiene, these oxygen atoms have a very clean reaction that gives rise to propylene formation. By including a suitable additive, and by looking at the formation of propene versus the [additive]/[1,2-butadiene] ratio, the absolute values of the various O(3P) + unsaturated hydrocarbon interactions can be evaluated. These rate constants increase with the number of substituents attached to the double bond. Moreover, a correlation between the total rate constants and ionization potentials is also observed.

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