Low-pressure study of the reactions of Cl atoms with acrylic acid and allyl alcohol (original) (raw)
Related papers
Gas-phase reaction of chlorine atoms with acrylonitrile. Temperature and pressure dependence
Chemical Physics Letters
The kinetics and mechanism of the reaction of chlorine atoms with acrylonitrile (CH 2 CHCN) (1) have been studied by the mass spectrometric discharge-flow method in the temperature range (260-333) K and at a total pressure between 0.5 and 3 Torr. At 1.0 Torr the following Arrhenius expression for the rate constant has been obtained from the kinetics of Cl radical consumption in excess of CH 2 CHCN: k 1 ¼ ð5:2 AE 1:6Þ Â 10 À14 exp½ð1400 AE 100=T Þ cm 3 molecule À1 s À1 . The reaction is found to proceed through an addition mechanism involving a relatively stable adduct. The atmospheric significance of the present results for acrylonitrile is also discussed.
Journal of Atmospheric Chemistry, 2000
The reaction of Cl with cyclohexanone (1) was investigated, for the first time, as a function of temperature (273-333 K) and at a low total pressure (1 Torr) with helium as a carrier gas using a discharge flow-mass spectrometry technique (DF-MS). The resulting Arrhenius expression is proposed, k 1 = (7.7 ± 4.1) × 10 −10 exp[-(540 ± 169)/T]. We also report a mechanistic study with the quantitative determination of the products of the reaction of Cl with cyclohexanone. The absolute rate constant derived from this study at 1 Torr of total pressure and room temperature is (1.3 ± 0.2) × 10 −10 cm 3 molecule −1 s −1 . A yield of 0.94 ± 0.10 was found for the H-abstraction channel giving HCl. In relative studies, using a newly constructed relative rate system, the decay of cyclohexanone was followed by gas chromatography coupled with flame-ionisation detection. These relative measurements were performed at atmospheric pressure with synthetic air and room temperature. Rate constant measured using the relative method for reaction (1) is: (1.7 ± 0.3) × 10 −10 cm 3 molecule −1 s −1 . Finally, results and atmospheric implications are discussed and compared with the reactivity with OH radicals.
International Journal of Chemical Kinetics, 2010
The rate coefficient for the gas-phase reaction of chlorine atoms with acetone was determined as a function of temperature (273-363 K) and pressure (0.002-700 Torr) using complementary absolute and relative rate methods. Absolute rate measurements were performed at the low-pressure regime (∼2 mTorr), employing the very low pressure reactor coupled with quadrupole mass spectrometry (VLPR/QMS) technique. The absolute rate coefficient was given by the Arrhenius expression k(T ) = (1.68 ± 0.27) × 10 −11 exp[-(608 ± 16)/T ] cm 3 molecule −1 s −1 and k(298 K) = (2.17 ± 0.19) × 10 −12 cm 3 molecule −1 s −1 . The quoted uncertainties are the 2σ (95% level of confidence), including estimated systematic uncertainties. The hydrogen abstraction pathway leading to HCl was the predominant pathway, whereas the reaction channel of acetyl chloride formation (CH 3 C(O)Cl) was determined to be less than 0.1%. In addition, relative rate measurements were performed by employing a static thermostated photochemical reactor coupled with FTIR spectroscopy (TPCR/FTIR) technique. The reactions of Cl atoms with CHF 2 CH 2 OH (3) and ClCH 2 CH 2 Cl (4) were used as reference reactions with k 3 (T ) = (2.61 ± 0.49) × 10 −11 exp[−(662 ± 60)/T ] and k 4 (T ) = (4.93 ± 0.96) × 10 −11 exp[−(1087 ± 68)/T] cm 3 molecule −1 s −1 , respectively. The relative rate coefficients were independent of pressure over the range 30-700 Torr, and the temperature dependence was given by the expression k(T ) = (3.43 ± 0.75) × 10 −11 exp[−(830 ± 68)/T ] cm 3 molecule −1 s −1 and k(298 K) = (2.18 ± 0.03) × 10 −12 cm 3 molecule −1 s −1 . The quoted errors limits (2σ ) are at the 95% level of confidence and do not include systematic uncertainties. C 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: [724][725][726][727][728][729][730][731][732][733][734] 2010
Kinetic study of the gas-phase reaction of atomic chlorine with a series of aldehydes
Atmospheric Chemistry and Physics, 2005
The reactions of Cl atoms with a series of unsaturated aldehydes have been investigated for the first time using a relative method. In order to obtain additional information for a qualitative structure versus reactivity discussion, we have also determined the rate coefficients for the reactions of atomic chlorine with their respective saturated aldehydes. These relative measurements were performed at room temperature and atmospheric pressure of air and N 2 , by using ethane, propene and 1-butene as reference compounds. The weighted average relative rate constants obtained, k Cl ±2σ (in units of cm 3 molecule −1 s −1 ) were: trans-2-pentenal (1.31±0.19)×10 −10 ; trans-2-hexenal (1.92±0.22)×10 −10 ; trans-2-heptenal (2.40±0.29)×10 −10 ; n-pentanal (2.56±0.27)×10 −10 ; n-hexanal (2.88±0.37)×10 −10 ; n-heptanal (3.00±0.34)×10 −10 .
Atmospheric Environment, 2007
Rate coefficients for the reactions of hydroxyl radicals and chlorine atoms with acrylic acid and acrylonitrile have been determined at 298 K and atmospheric pressure. The decay of the organics was followed using a gas chromatograph with a flame ionization detector (GC-FID) and the rate constants were determined using a relative rate method with different reference compounds. Room temperature rate constants are found to be (in cm 3 molecule À1 s À1): k 1 (OH+CH 2 Q CHC(O)OH) ¼ (1.7570.47) Â 10 À11 , k 2 (Cl+CH 2 QCHC(O)OH) ¼ (3.9970.84) Â 10 À10 , k 3 (OH+CH 2 QCHCN) ¼ (1.1170.33) Â 10 À11 and k 4 (Cl+CH 2 QCHCN) ¼ (1.1170.23) Â 10 À10 with uncertainties representing 72s. This is the first kinetic study for these reactions under atmospheric pressure. The rate coefficients are compared with previous determinations taking into account the effect of pressure on the rate constants. The effect of substituent atoms or groups on the overall rate constants is analyzed in comparison with other unsaturated compounds in the literature. In addition, atmospheric lifetimes based on the homogeneous sinks of acrylic acid and acrylonitrile are estimated and compared with other tropospheric sinks for these compounds.
Atmospheric Environment, 2005
Absolute rate coefficients have been measured for the first time as a function of temperature for the gas phase reactions of chlorine atoms with a series of aliphatic acetates: methyl acetate (k 1 ), ethyl acetate (k 2 ), n-propyl acetate (k 3 ) and n-butyl acetate (k 4 ). The experiments were carried out using the pulsed laser photolysis-resonance fluorescence technique (PLP-RF), over the temperature range 265-383 K. The obtained kinetic data were used to derive the Arrhenius expressions: k 1 ¼ ð9:31 AE 1:02Þ Â 10 À12 exp½Àð359 AE 70Þ=T; k 2 ¼ ð4:35 AE 0:65Þ Â 10 À12 exp½ð342 AE 92Þ=T; k 3 ¼ ð2:22 AE 0:20Þ Â 10 À11 exp½ð217 AE 58Þ=T and k 4 ¼ ð5:41 AE 1:51Þ Â 10 À11 exp½ð245 AE 168Þ=T (in units of cm 3 molecule À1 s À1 ). The rate constants obtained at room temperature were as follows: methyl acetate, 0.27970.031; ethyl acetate, 1.3770.20; n-propyl acetate, 4.6070.41 and n-butyl acetate, 12.373.4 (in units 10 À11 cm 3 molecule À1 s À1 ). The results are discussed in terms of structure-reactivity relationships and the atmospherics implications are also analyzed. r
Chemical Physics Letters, 2009
The kinetics of the reactions of Cl atoms with three unsaturated carbonyl compounds at 298 K and atmospheric pressure were investigated for the first time using the GC-FID technique. Rate coefficients (in cm 3 molecule À1 s À1 ) of k 1 (Cl + CH 2 @CHC(O)CH 2 CH 3 ) = (2.91 ± 1.10) Â 10 À10 , k 2 (Cl + CH 2 @CHOC(O)CH 2 -CH 3 ) = (2.06 ± 0.36) Â 10 À10 and k 3 (Cl + CH 2 @CHC(O)OCH 2 CH 3 ) = (2.53 ± 0.46) Â 10 À10 were obtained using the relative rate method with different references. Structure activity relationships (SARs) were developed for the reactions of Cl with a wide range of unsaturated compounds. On the basis of our kinetic measurements, tropospheric lifetimes of the studied unsaturated compounds are estimated.
International Journal of Chemical Kinetics, 2005
The relative rate technique has been used to determine the rate constants for the reactions Cl + CH 3 OCHCl 2 → products and Cl + CH 3 OCH 2 CH 2 Cl → products. Experiments were carried out at 298 ± 2 K and atmospheric pressure using nitrogen as the bath gas. The decay rates of the organic species were measured relative to those of 1,2-dichloroethane, acetone, and ethane. Using rate constants of (1.3 ± 0.2) × 10 −12 cm 3 molecule −1 s −1 , (2.4 ± 0.4) × 10 −12 cm 3 molecule −1 s −1 , and (5.9 ± 0.6) × 10 −11 cm 3 molecule −1 s −1 for the reactions of Cl atoms with 1,2-dichloroethane, acetone, and ethane respectively, the following rate coefficients were derived for the reaction of Cl atoms (in units of cm 3 molecule −1 s −1 ) with CH 3 OCHCl 2 , k = (1.04 ± 0.30) × 10 −12 and CH 3 OCH 2 CH 2 Cl, k = (1.11 ± 0.20) ×10 −10 . Errors quoted represent two σ , and include the errors due to the uncertainties in the rate constants used to place our relative measurements on an absolute basis. The rate constants obtained are compared with previous literature data and used to estimate the atmospheric lifetimes for the studied ethers. C 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: [420][421][422][423][424][425][426] 2005