Kinetic studies of OH and O3 reactions with allyl and isopropenyl acetate (original) (raw)
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International Journal of Chemical Kinetics, 1998
Rate constants for the reaction of ozone with methylvinyl ketone (H 2 C " CHC(O)CH 3 ), methacrolein (H 2 C" C(CH 3 )CHO), methacrylic acid (H 2 C "C(CH 3 )C(O)OH), and acrylic acid (H 2 C " CHC(O)OH) were measured at room temperature in the pres-(296 Ϯ 2 K) ence of a sufficient amount of cyclohexane to scavenge OH-radicals. Results from pseudofirst-order experiments in the presence of excess ozone were found not to be consistent with relative rate measurements. It appeared that the formation of the so-called Criegee-intermediates leads to an enhanced decrease in the concentration of the two organic acids investigated. It is shown that the presence of formic acid, which is known to react efficiently with Criegee-intermediates, diminishes the observed removal rate of the organic acids. The rate constant for the reaction of ozone with the unsaturated carbonyl compounds methylvinyl ketone and methacrolein was found not to be influenced by the addition of formic acid. Rate constants for the reaction of ozone determined in the presence of excess formic acid are in ): methylvinyl ketone methacrolein 3 Ϫ1 Ϫ1 Ϫ18 cm molecule s (5.4 Ϯ 0.6) ϫ 10 ; (1.3 Ϯ 0.14) ϫ methacrylic acid and acrylic acid Results are Ϫ18 Ϫ18 Ϫ18
Kinetic Studies of OH Reactions with a Series of Methyl Esters
The Journal of Physical Chemistry A, 1997
Absolute rate constants have been measured for the gas-phase reactions of hydroxyl radicals with a series of methyl esters: methyl propionate (k 1), methyl butyrate (k 2), methyl valerate (k 3), and methyl caproate (k 4). Experiments were carried out using the pulsed laser photolysis-laser induced fluorescence technique over the temperature range 253-372 K. The obtained kinetic data were used to derive the following Arrhenius expressions: k 1) (1.45 (0.42) × 10-12 exp[-(148 (86)/T]; k 2) (0.96 (0.29) × 10-12 exp[(380 (91)/T]; k 3) (1.37 (0.64) × 10-12 exp[(401 (142)/T]; k 4) (2.46 (1.04) × 10-12 exp[(326 (130)/T] (in units of cm 3 molecule-1 s-1). At room temperature, the rate constants obtained (in units of 10-12 cm 3 molecule-1 s-1) were as follows: methyl propionate (0.83 (0.09); methyl butyrate (3.30 (0.25); methyl valerate (4.83 (0.55); methyl caproate (7.15 (0.70). Our results are compared with the previous determinations and discussed in terms of structure-activity relationships.
Kinetics of the reaction of O3 with selected benzenediols
International Journal of Chemical Kinetics, 2003
The kinetics of the reaction of O 3 with the aromatic vicinal diols 1,2-benzenediol, 3-methyl-1,2-benzenediol, and 4-methyl-1,2-benzenediol have been investigated using a relative rate technique. The rate coefficients were determined in a 1080-L smog chamber at 298 K and 1 atm total pressure of synthetic air using propene and 1,3-butadiene as reference compounds. The following O 3 reaction rate coefficients (in units of cm 3 molecule −1 s −1 ) have been obtained: k(1,2-benzenediol) = (9.60 ± 1.12) × 10 −18 , k(3-methyl-1,2-benzenediol) = (2.81 ± 0.23) × 10 −17 , k(4-methyl-1,2-benzenediol) = (2.63 ± 0.34) × 10 −17 . Absolute measurements of the O 3 rate coefficient have also been carried out by measuring the decay of the dihydroxy compound in an excess of O 3 . The results from these experiments are in good agreement with the relative determinations. Atmospheric implications are discussed. C
Journal of Atmospheric Chemistry, 1998
Using a relative rate method, rate constants have been measured for the gas-phase reactions of OH and NO3 radicals with pinonaldehyde, caronaldehyde and sabinaketone at 296 ± 2 K. The OH radical reaction rate constants obtained are (in units of 10−12 cm3 molecule−1 s−1): pinonaldehyde, 48 ± 8; caronaldehyde, 48 ± 8; and sabinaketone, 5.1 ± 1.4, and the NO3 radical reaction rate constants are (in units of 10−14 cm3 molecule−1 s−1): pinonaldehyde, 2.0 ± 0.9; caronaldehyde, 2.5 ± 1.1; and sabinaketone, 0.036 ± 0.023, where the error limits include the estimated overall uncertainties in the rate constants for the reference compounds. Upper limits to the O3 reaction rate constants were also obtained, of <2 × 10−20 cm3 molecule−1 s−1 for pinonaldehyde and caronaldehyde, and <5 × 10−20 cm3 molecule−1 s−1 for sabinaketone. These reaction rate constants are combined with estimated ambient tropospheric concentrations of OH radicals, NO3 radicals and O3 to calculate tropospheric lifetimes and dominant transformation process(es) of these and other monoterpene reaction products.
Atmospheric Environment, 2010
Relative kinetic studies have been performed on the reactions of Cl atoms with a series of methyl alkyl esters in a 405-liter borosilicate glass chamber at (298 AE 3) K and one atmosphere of synthetic air using in situ FTIR spectroscopy to monitor the reactants. Rate coefficients (in units of cm 3 molecule À1 s À1 ) were determined for the following compounds: methyl acetate (2.48 AE 0.58) Â 10 À12 ; methyl propanoate (1.68 AE 0.36) Â 10 À11 ; methyl butanoate (4.77 AE 0.87) Â 10 À11 ; methyl pentanoate (7.84 AE 1.15) Â 10 À11 ; methyl hexanoate (1.09 AE 0.31) Â 10 À10 ; methyl heptanoate (1.56 AE 0.37) Â 10 À10 ; methyl cyclohexane carboxylate (3.32 AE 0.76) Â 10 À10 ; methyl-2-methyl butanoate (9.41 AE 1.39) Â 10 À11 .
Atmospheric Environment, 2011
Using the relative rate technique, rate constants for the gas-phase reactions of hydroxyl radicals with n-propyl vinyl ether (k 1), 2-chloroethyl vinyl ether (k 2), allyl ether (k 3) and allyl ethyl ether (k 4) have been measured. Experiments were carried out at (298 AE 2) K and atmospheric pressure using N 2 and ultra pure air as bath gas. Using isoprene, 1-methyl-1-cyclohexene, 2-methyl-2-butene, 3-buten-1-ol and 2-methyl-2-propen-1-ol as reference compounds, the following rate constants were derived: k 1 ¼ (11.0 AE 0.4) Â 10 À11 , k 2 ¼ (9 AE 1) Â 10 À11 , k 3 ¼ (6.8 AE 0.7) Â 10 À11 and k 4 ¼ (4.2 AE 0.7) Â 10 À11 , in units of cm 3 molecule À1 s À1. This is the first experimental detcermination of k 2 ek 4. The rate constants obtained are compared with the previous literature data for corresponding alkenes reactions with OH and the observed reactivity trends are discussed. The atmospheric implications of the results are considered.
Kinetic study of the OH reaction with some hydrochloroethers under simulated atmospheric conditions
Atmospheric Environment, 2010
Using the relative rate technique, rate constants for the gas-phase reactions of hydroxyl radicals with 2-chloroethyl methyl ether (k 1), 2-chloroethyl ethyl ether (k 2) and bis(2-chloroethyl) ether (k 3) have been measured. Experiments were carried out at (298 AE 2) K and atmospheric pressure using synthetic air as bath gas. Using n-pentane and n-heptane as reference compounds, the following rate constants were derived: k 1 ¼ (5.2 AE 1.2) Â 10 À12 , k 2 ¼ (8.3 AE 1.9) Â 10 À12 and k 3 ¼ (7.6 AE 1.9) Â 10 À12 , in units of cm 3 molecule À1 s À1. This is the first experimental determination of k 2 and k 3 under atmospheric pressure. The rate constants obtained are compared with previous literature data and the observed trends in the relative rates of reaction of hydroxyl radicals with the ethers studied are discussed. The atmospheric implications of the results are considered in terms of lifetimes and fates of the hydrochloroethers studied.
Atmospheric oxidation of α,β-unsaturated ketones: kinetics and mechanism of the OH radical reaction
Atmospheric Chemistry and Physics, 2021
The OH-radical-initiated oxidation of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one was investigated in two atmospheric simulation chambers at 298 ± 3 K and 990 ± 15 mbar using long-path FTIR spectroscopy. The rate coefficients of the reactions of 3-methyl-3-penten-2one and 4-methyl-3-penten-2-one with OH radicals were determined to be (6.5 ± 1.2) × 10 −11 and (8.1 ± 1.3) × 10 −11 cm 3 molecule −1 s −1 , respectively. To enlarge the kinetics data pool the rate coefficients of the target species with Cl atoms were determined to be (2.8±0.4)×10 −10 and (3.1± 0.4) × 10 −10 cm 3 molecule −1 s −1 , respectively. The mechanistic investigation of the OH-initiated oxidation focuses on the RO 2 +NO reaction. The quantified products were acetoin, acetaldehyde, biacetyl, CO 2 and peroxyacetyl nitrate (PAN) for the reaction of 3-methyl-3-penten-2-one with OH radicals and acetone, methyl glyoxal, 2-hydroxy-2-methylpropanal, CO 2 and peroxyacetyl nitrate (PAN) for the reaction of 4methyl-3-penten-2-one with OH, respectively. Based on the calculated product yields an upper limit of 0.15 was determined for the yield of RONO 2 derived from the OH reaction of 4-methyl-3-penten-2-one. By contrast, no RONO 2 formation was observed for the OH reaction of 3-methyl-3-penten-2-one. Additionally, a simple model is presented to correct product yields for secondary processes.