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1.
Rate constants for the reaction of O(3P) atoms with C3H4, C3H6 and NO(M = N2O) have been measured over the temperature range 300–392°K using a modulation-phase shift technique. The Arrhenius expressions obtained are:C2H4, k2 = 3.37 × 109 exp[?(1270 ± 200)/RT]liter mole?1 sec?1,C3H6, k2 = 2.08 × 109 exp[?(0 ± 300)/RT]liter mole?1 sec?1,NO(M = N2O), k1 = 9.6 × 109 exp[(900 ± 200/RT]liter2 mole?2 sec?1.These temperature dependencies of k2 are in good agreement with recent flash photolysis-resonance flourescence measurements, although lower than previous literature values.  相似文献   

2.
Rate coefficients for collisional removal of O(1D) by six atmospheric gases have been measured by monitoring the appearance of O(3P) following photolytic production of O(1D). The measured values, kM±2σ, in units of 10?11 cm?3 molecule ?1 s?1 are kO3 = 22.8±2.3, kN2 = 2.52 ± 0.25, kCO2 = 10.4 ± 1.0,kH2O 195± 2.0, kN2O = 11.7 ± 1.2, and kH2, = 11.8±1.2.  相似文献   

3.
The rate constant for the reaction or NH3 + OH → NH2 + H2O has been measured in a high temperature fast flow reactor over the range 294–1075 K k = (5.41 ± 0.86) × 10-12 exp[?(2120 ± 143) cal mole?1/RT cm3 molecule?1 s?1. This result is compared with literature values and discussed.  相似文献   

4.
Absolute rate constants for the reaction of O(3P) atoms with n-butane (k2) and NO(M  Ar)(k3) have been determined over the temperature range 298–439 K using a flash photolysis-NO2 chemiluminescence technique. The Arrhenius expressions obtained were k2 = 2.5 × 10?11exp[-(4170 ± 300)/RT] cm3 molecule?1 s?1, k3 = 1.46 × 10?32 exp[940 ± 200)/ RT] cm6 molecule?2 s?1, with rate constants at room temperature of k2 = (2.2 ± 0.4) × 10?14 cm3 molecule?1 s?1 and k3 = (7.04 ± 0.70)×10?32 cm6 molecule?2 s?1. These rate constants are compared and discussed with literature values.  相似文献   

5.
The rate constants for the reactions C2O + H → products (1) and C2O + H2 → products (2) have been determined at room temperature by means of laser-induced fluorescence detection of C2O radicals, generated either by the KrF excimer laser photolysis Of C3O2, or by the reaction of C3O2 with O atoms. Values of k1 = (3.7 ± 1.0) × 10?11 cm3 s?1 and k2 = (7 ± 3) × 10?13 cm3 s?1 were obtained.  相似文献   

6.
The rate constant for the reaction NH3 + OH → NH2 + H2O was determined by the comparison of the calculated induction period data with experiments by the shock tube technique in the range 1360–1840 K, for NH3-H2-O2-Ar mixtures. The rate constants can be represented by the expression k = 1012.49±0.04exp[(?1.95±0.15) kcal/,RT] cm3 mol?1 s?1.  相似文献   

7.
A combined EPR/LMR spectrometer and fast-flow system has been used to investigate the reactions HO2 + NO(k1), HO2 + OH(k2), HO2 + HO2(k3) at room temperature. The rate constants have been measured: k1 = (7.0 ± 0.6) × 10?12 cm3 s?1 (P = 7–10 Torr);k2 = (5.2 ± 1.2) × 10?11 cm3 s?1 (P = 8–10 Torr);k3 = (1.65 ± 0.3) × 10?12 cm3 s?1 (P = 2.1–24.9 Torr). The conclusion is drawn from analysis of the literature and the present work that k2 and k3 do not depend on pressure up to 1 atm.  相似文献   

8.
The rates of decay of O(3P) atoms in H2/CO/N2 mixtures in a discharge flow system have been measured, using O + CO chemiluminescence. The mechanism is: O + H2 → OH + H (1), O + OH → O2 + H (2), CO + OH → CO2 + H (3). At 425 K, k2/k3 = 260 ± 20; literature values of k3 combine to yield k2 = (2.65 ± 0.52) × 1010 dm3 mol?1 s?1.  相似文献   

9.
Flash photolysis of NO coupled with time resolved detection of O via resonance fluorescence has been used to obtain rate constants for the reaction O + NO + N2 → NO2 + N2 at temperatures from 217 to 500 K. The measured rate constants obey the Arrhenius equation k = (15.5 ± 2.0) × 10?33 exp(1160 ± 70)/1.987 T] cm6 molecule?2 s?1. An equally acceptable equation describing the temperature dependence of k is k = 3.80 × 10?27/T1.82 cm6 molecule?2 s?1. These results are discussed and compared with previous work.  相似文献   

10.
The rate constant for the formation of H+5 (D+5) at (86 ± 3) °K by the three-body process has been determined (k3(H) = (2.16 ± 0.10) × 10?28 × 10?28 cm6/molecule2 sec and k3(D) = (1.47 ± 0.20) × 10?28 cm6/molecule2 sec) in a high pressure mass spectrometer. Comparison of this result with published rate data at 300 °K indicates the reaction has an apparent activation energy of ?1.5 kcal/mole.  相似文献   

11.
The reactions of CH3O2 with SO2 and NO have been studied by steady state photolysis of azomethane in the presence of O2SO2→NO mixtures at 296 K and 1 atm total pressure. The quantum yield of NO oxidation by CH3O2 radicals is increased substantially when SO2 is added to the system indicating an SO2 induced chain oxidation of NO. The rate law gives k1/k2 = (2.5 ± 0.5) × 10?3 for CH3O2 + SO2 → CH3O2SO2 (1), CH3O2 + NO → CH3O + NO2 (2). Combining this ratio with the absolute value of k1 = 8.2 × 10?15 cm3 s?1 gives k2 = 10?11.5 ± 02 cm3 s?1.  相似文献   

12.
H.F. Rexroat  N.S. Rowan 《Polyhedron》1985,4(8):1357-1363
trans-[Co(en)2(SO3)(H2O)]+ reacts with imidazole (ImH) and imidazole containing ligands (L) to form trans-[Co(en)2(SO3)L]+ in the pH range 6.0–9.0. The complex seems to react both in the hydroxy and in the aquo form. The rate constant for the reaction of imidazole with the aquo form is 6.0±0.7 and 4±1M?1s?1 for the reaction with the hydroxy form at 25°C. The apparent equilibrium constant for formation of the imidazole complex at pH 7 is consistent with the value of 3 x 102 measured previously. Appreciable amounts of complex form only in the pH 6–9 range. Above pH 9 NMR spectra show that even the immediate products are different. In aged solutions at all pHs other products form.  相似文献   

13.
The rate constant for the reaction between OH and vibrationally excited H2, OH + H2(ν = 1)→H2O + H, has been measured directly at 298 K. k01 is found to be (7.5±3)×10?13 cm3/molecules, corresponding to a vibrational rate enhancement of k01/k00 = (1.2 ± 0.4) × 102.  相似文献   

14.
The kinetics of the reaction NH2 + NO → N2 + H2O were studied, using a conventional flash photolysis system. A value of k1 = (1.1 ± 0.2) × 1010 & mole?1 s?1 was obtained at room temperature and in the pressure range 2–700 torr in the presence of nitrogen. A slight negative temperature coefficient was observed between 300 and 500 K, equivalent to a negative activation energy of 1.05 ± 0.2 kcal mole?1.  相似文献   

15.
The kinetics of reactions involving the ground-state azide radical, N3 (X2Πg, have been investigated in a discharge-flow system using mass spectrometric detection with molecular-beam sampling. The following rate constants have been determined at 295 K: Cl + N3Cl → Cl2 + N3,k295 = (1.78 ± 0.26) × 10?12 cm3 s?1 (1σ): N3 + NO → N2O + N2, k295 = (1.19 ± 0.31) × 10.?12 cm3 s?1 (1σ). A method for determining absolute N3 radical concentration is reported.  相似文献   

16.
The rate constants for the reactions OH(X2Π, ν = O) + NH3k1 H2O + NH2 and OH(X2Π, ν = O) + O3k2 → HO2 + O2 were measured at 298°K by the flash photolysis resonance fluorescence technique. The values of the rate constants thus obtained are K1 = (4.1 ± 0.6) × 10?14 and k2 = (6.5 ± 1.0) × 10?14 in units of cm3 molecule ?1 sec1. The results are discussed in terms of understanding the dynamics of the perturbed stratosphere.  相似文献   

17.
NH(A3Π → X3Σ?) and OH(A2Σ+ → X2Π) chemiluminescences from the reaction of CH(X2Π) with NO and O2, respectively, have been observed at room temperature. From the decay of such emissions we have measured the rate constants for these two reactions: kNO = (2.5 ± 0.5) × 10?10 and kO2 = (8 ± 3) × 10?11 cm3 molecule ?1 s?1, which are in agreement with previously reported rates determined by direct CH(X) detection using, laser-induced fluorescence. This indicates that a four-centered mechanism generating these excited species is operative in both reactions. The CH generation from 266 nm photolysis of CHBr3 has also been investigated via analysis of CH* emissions.  相似文献   

18.
The absolute rate constant of the reaction of NH2 with NO2 has been measured using a flash-photolysis laser resonance-fluorescence technique. The value obtained at room temperature is k1 = 2.3 (± 0.2) × 10?11 cm3 molecule ?1 s?1. A negative temperature coefficient has been found between 298 and 505 K for this reaction, k1 = 3.8 × 10?8 × T?1.30 cm3 molecule?1 s?1. It is thought that this is the major reaction of NH2 in the troposphere.  相似文献   

19.
Excited iodine atoms I(2P12) are formed by laser irradiation of C2F5I at 2950 Å. The mean radiative lifetime τ of these metastable atoms and their bimolecular rate constant k2 for deactivation in collissions with C2F5I were measured to be: τ = 108 ± 10 ms; k2 = (1.8 ± 0.1) × 10?17 cm3/molec s.  相似文献   

20.
The reaction of O2(1Δg) with HO2(X?) was studied in an isothermal flow reactor in the pressure range 7?p? 10.7 mbar at temperatures between 299?T? 423 K. H-atom production was observed in the reaction O2(1Δg) + HO22A′) - H(2S)+ 2O2 (3Σg?). The rate of this reaction (k1) is estimated to be k1 = (1 ± 0.5) × 1014 CM3 Mol?1 s?1. The implications of this reaction to recent determinations of the rate of the reaction H + O2(1Δg) are discussed.  相似文献   

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