摘要:

AbstractProcedures are discussed to correct for nonideality in a shock tube used in the reflected mode in conjunction with flash photolysis and atomic resonance absorption to measure chemical kinetics of atoms at high temperatures. Experimentally, pressure time profiles for the incident and reflectedshock regions are made close to the location of the observation windows through which absorbance is measured. The corresponding temperatures are calculated from the adiabatic equation of state. Justification for this procedure is provided by extending Mirels' boundary layer theory to take intoaccount interaction of the reflected wave with the flowing gas in the free stream and in the boundary layer. These theoretical methods are described for calculating the thermodynamic and hydrodynamic states behind the reflected wave from initial values of pressure and temperature and the measured velocity of the incident wave. The implication of these results to kinetic measurements at high temperature is discussed.

ISSN:0538-8066    

DOI:10.1002/kin.550180402

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe hydrogen transfer reaction between C2H6and CF3radicals, generated by the photolysis of CF3I, has been studied in the temperature range 298–617 K. The rate constant, based on the value of 1013.36cm3mol−1s−1for the recombination of CF3radicals, is given by\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k_2 = (11.90 \pm 0.09) - (33230 \pm 740)/19.145T $$\end{document}wherek2is in cm3mol−1s−1and E is in J mol−1. These results are compared with those previously reported, and the following best value fork2is recommended:\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k_2 = (11.94 \pm 0.07) - (33670 \pm 540)/19.145T $$\e

ISSN:0538-8066    

DOI:10.1002/kin.550180403

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe reaction kinetics of carbon dioxide with four alkanolamines of industrial importance (MEA, DGA, DEA, and DIPA) have been investigated with the aid of the stopped‐flow technique, allowing the determination of rate constants for carbamates formation. The constants obtained for MEA at 20°C and 25°C are in good agreement with recent literature data. The kinetic behavior of DGA was found to be almost identical to that of MEA.The rate constants obtained for DIPA at 25°C (54 M−1s−1) is half as large as that for DEA (110 M−1s−1). The former one is satisfactorily compared with the recent values proposed by Blauwhoff et al. Activation energies have also been obtained for DEA (23.2 kJ mol−1) and for DIPA (58.7 kJ mol−1) and their mechanistic implications are discussed in relation with the relevanceof a rate‐determining proton transfer step in the process of c

ISSN:0538-8066    

DOI:10.1002/kin.550180404

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe influence of the effective potential energy curves on the calculation of the strong collision limiting low‐pressure rate coefficients of thermal dissociation‐recombination reactions was analyzed in terms of the factorized formalism of Troe. An analysis of 26 reactions employing a Morse potential coupled with a quasitriatomic molecular model and an explicit account of the adiabatic zero‐point barriers, as originallyproposed by Troe, was performed. A comparison between calculations realizedwith an exactly fitted looseness parameter, α, and with a standard value of α = 1.0 Å−1, indicates that the use of this last value is satisfactorily justified in the evaluation of thestrong collision limiting low‐pressure rate coefficients. A study interms of restrictive relationships between the looseness and Morse parameters andab initio, radial potentials (for CH4, CH3O2, and HO2) was also realized. The uncertainties in the evaluation of termolecular rate coefficients due to the lack of a complete knowledge of the long‐range potentials are also bri

ISSN:0538-8066    

DOI:10.1002/kin.550180405

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe reactants, products, and saddle point for the reaction H2+ CN → H + HCN have been studied byab initiocalculations. The computed structures, frequencies, and energetics are compared directly to available measurements and, indirectly, to experimental rateconstants. The theoretical rate constants used in the comparison are calculated with conventional transition state theory. By reduction of the computed reaction barrier to 4.1 kcal mol,−1good agreement with experimental rate constants is obtained over a 3250‐K temperature range. This computed rate constant is well represented by the form 4.9 × 10−18T2.45e−1, 126/Tover the temperature range of 250 K–3500 K. Substantial reaction rate curvature is found due to low‐frequency bending modes at the saddle point. The results for this reaction are compared to other abstraction reactions involving H atom transfer to identify correlations between reaction exothermicity and both abstraction barriers and reaction

ISSN:0538-8066    

DOI:10.1002/kin.550180406

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractAbsolute rate constants for the gas phase reaction of OH radicals with pyrrole (k1) and thiophene (k2) have been measured over the temperature ranges 298–440 and 274–382 K, respectively, using the flash photolysis‐resonance fluorescence technique. The rate constants obtained were independent of the total pressure of argon diluent over the range 25–100 torr andwere fit by the Arrhenius expressions\documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 = (2.7 \pm _{0.6} ^{0.8}) \times 10^{ - 11} \exp [(403 \pm 93)/T]{\rm cm}^{\rm 3} {\rm molecule}^{{\rm - 1}} {\rm s}^{{\rm - 1}} $$\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$$ k_2 = (1.2_{ - 0.6} ^{ + 1.0}) \times 10^{ - 12} \exp [(584 \pm 217)/]{\rm cm}^{\rm 3} {\rm molecule}^{{\rm - 1}} {\rm s}^{{\rm - 1}} $$\end{document}with rate constants at 298 ± 2 K ofk1= (1.03 ± 0.06) × 10−10cm3molecule−1s−1andk2= (8.9 ± 0.7) × 10−12cm3molecule−1s−1. [These errors represent two standard deviations (systematic errors could constitute an additional ca. 10% uncertainty)]. These results are discussed with respect to the previous literature data and the atmospheric lifetimes

ISSN:0538-8066    

DOI:10.1002/kin.550180407

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe first stage thermal reactions of CF2CICH3in the presence of chlorine have been studied between 554 and 614 K. These areand\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm CF}_{\rm 2} {\rm CICH}_{\rm 3} {\rm + CI}_{\rm 2} \to {\rm CF}_{\rm 2} {\rm CICH}_{\rm 2} {\rm CI + HCI} $$\end{document}Rate equations derived from a radical mechanism are shown to fit the experimental results. Values of Arrhenius parameters for the decomposition of the CF2ClCH2. radical and its reactions with Cl2and Cl are given.

ISSN:0538-8066    

DOI:10.1002/kin.550180408

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe rate constants of O2(1Δg) with aliphatic alcohols, terpenes, unsaturated hydrocarbons, chlorinated hydrocarbons, oxygen, and diamines have been studied in thepresence of NO2. The rate constants for oxygen, 1,2‐ethane diamine, and 1,2‐propane diamine are (9.9 ± 0.4) × 102, (8.7 ± 0.7) × 104, and (1.4 ± 0.3) × 1041/mol/s, respectively. The rate constants for all other compounds are less than the oxygen rat

ISSN:0538-8066    

DOI:10.1002/kin.550180409

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550180401

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY