摘要:

AbstractThe kinetics and products of the decomposition of 9‐diazofluorene bytris(p‐bromophenyl) aminium hexachloroantimonate in acetonitrile solvent has been investigated. The reaction is first order with respect to the concentration of both 9‐diazofluorene andtris(p‐bromophenyl) aminium hexachloroantimonate. A reaction mechanism has also been p

ISSN:0538-8066    

DOI:10.1002/kin.550211202

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe gas phase reaction of OH radicals with dimethyl sulfide (CH3SCH3, DMS) has been studied using both an absolute and a relative technique at 295 ± 2 K and a total pressure of 1 atm. The absolute rate technique of pulse radiolysis combined with kinetic spectroscopy was applied. Using this technique a rate constant of (3.5 ± 0.2) × 10−12cm3molecule−1s−1was obtained. For the relative rate method, rate constants for the reaction of OH with DMS were found to increase with increasing concentrations of added NO. These results are compared with the large body of kinetic and mechanistic data previously reported in the li

ISSN:0538-8066    

DOI:10.1002/kin.550211203

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractUsing Fourier transform infrared spectroscopy, the ethene yield from the reaction of C2H5radicals with O2has been determined to be 1.50 ± 0.09%, 0.85 ± 0.11%, and<0.1% at total pressures of 25, 50, and 700 torr, respectively. Additionally, the rate constant of the reaction of C2H5radicals with molecular chlorine was measured relative to that with molecular oxygen.A ratiok6/k7= 1.99 ± 0.14 was measured at 700 torr total pressure which, together with the literature value ofk7= 4.4 × 10−12cm3molecule−1s−1, yieldsk6= (8.8 ± 0.6) × 10−12cm3molecule−1s−1. Quoted errors represent 2σ. These results are discussed with respect to previous kinetic and mechanistic studi

ISSN:0538-8066    

DOI:10.1002/kin.550211204

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractUsing a relative rate method, rate constants for the gas‐phase reactions of the OH radical with 1‐ and 2‐propyl nitrate, 1‐ and 2‐butyl nitrate and 1‐nitrobutane have been determined in the presence of one atmosphere of air at 298 ± 2 K. Using rate constants for the reactions of the OH radical with propane and cyclohexane of 1.15 × 10−12and 7.49 × 10−12cm3molecule−1s−1, respectively, following rate constants (in units of 10−12cm3molecule−1s−1) were obtained: 1‐propyl nitrate, 0.62; 2‐propyl nitrate, 0.41; 1‐butyl nitrate, 1.78; 2‐butyl nitrate, 0.93; and 1‐nitrobutane, 1.35. These rate constants are compared

ISSN:0538-8066    

DOI:10.1002/kin.550211205

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe pressure‐jump method has been used to determine the rate constants for the formation and dissociation of nickel(II) and cobalt(II) complexes with cinchomeronate in aqueous solution at zero ionic strength. The forward and reverse rate constants obtained arekf= 2.27 × 106M−1s−1andkr= 3.81 × 101s−1for the nickel(II) complex andkf= 1.23 × 107M−1s−1andkr= 2.66 × 102s−1for the cobalt(II) complex at 25°C. The activation parameters of the reactions have also been obtained from the temperature variation study. The results indicate that the rate determining step of the reaction is a loss of a water molecule from the inner coordination sphere of the cation for the nickel(II) complex and the chelate ring closure for the cobalt(II) complex. The influence of the pyridine ring nitrogen atom of the cinchomeronate ligand on the complexation of cobalt(II) ion

ISSN:0538-8066    

DOI:10.1002/kin.550211206

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe gas‐phase reaction of methyl vinyl ketone with the OH radical, in the presence of NOx, was investigated at 298 ± 2 K and atmospheric pressure of air. Glycolaldehyde and methylglyoxal were observed to be the major products, with a combined yield of 0.89 ± 0.16. The sum of the yields of the two other main products, formaldehyde and peroxyacetyl nitrate, were found to be essentially unity. The product yield data for glycolaldehyde and methylglyoxal indicate that OH radical addition to the terminal carbon atom of the>CC

ISSN:0538-8066    

DOI:10.1002/kin.550211207

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractUncertainty sometimes exists in determining initial reaction rates from experimental data. A method, originally proposed by Wilkinson [9] for estimating orders and rate constants for simple batchnth order reactions, has been generalized to complex kinetic systems. This method yields very accurate initial rates for all systems and extends the conversion range of experimental investigation of initial rates well beyond the “zero‐order” region. Accurate initial rates are required in analytical methods used for screening alternate reaction mecha

ISSN:0538-8066    

DOI:10.1002/kin.550211208

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe reactions Br + NO2+M→ BrNO2+M(1) and I + NO2+M→ INO2+M(2) have been studied at low pressure (0.6‐2.2 torr) at room temperature and with helium as the third body by the discharge‐flow technique with EPR and mass spectrometric analysis of the species. The following third order rate constants were foundk1(0)= (3.7 ± 0.7) × 10−31andk2(0)= (0.95 ± 0.35) × 10−31(units are cm6molecule−2s−1). The secondary reactionsX+XNO2→X2+ NO2(X= Br, I) have been studied by mass spectrometry and their rate constants have been estimated from product analysis

ISSN:0538-8066    

DOI:10.1002/kin.550211209

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractUsing the flash photolysis resonance fluorescence technique, absolute rate constants were determined for the gas phase reactions of hydroxyl radicals with a series of aliphatic polyethers. At 298 K, the measured rate constants (in units of 10−12cm3molecule−1s−1) were: 2,2‐dimethoxypropane, (3.9 ± 0.2); 2,2‐diethoxypropane, (11.7 ± 1.3); 1,2‐dimethoxypropane, (14.3± 1.5); 2‐methoxyethylether, (17.5 ± 1.1); 2‐ethoxyethlyether, (26.8 ± 2.4); 1,1‐dimethoxyethane, (8.9 ± 1.0); and 1,1,3‐trimethoxypropane, (16.7 ± 1.0).The temperature dependencies of the rate constants for 2,2‐dimethoxypropane and 2,2‐diethoxypropane, reactions (1) and (2), were studied over the temperature range 240–440 K and are expressed by the Arrhenius equations:\documentclass{article}\pagestyle{empty}\begin{document}$$k_{\rm 1} = (3.55\,\, \pm 0.39)\,\, \times \,\,10^{ - 12} \,\,\exp [(30 \pm 35)\,/T]\,\,{\rm cm}^{\rm 3} \,\,{\rm molecule}^{{\rm - 1}} {\rm s}^{{\rm - 1}}$$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$k_{\rm 2} = (1.06\,\, \pm 0.25)\,\, \times \,\,10^{ - 11} \,\,\exp [(15 \pm 75)\,/T]\,\,{\rm cm}^{\rm 3} \,\,{\rm molecule}^{{\rm - 1}} {\rm s}^{{\rm - 1}}$$\end{document}Implications of the results are discussed in terms of reaction mechanisms and the prediction of gas phase OH radical reactio

ISSN:0538-8066    

DOI:10.1002/kin.550211210

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractCalculations were carried out on several data sets to study the mechanism of hydrogen abstraction from phenols by peroxy radicals:Rate constants,kvalues, were collected for the reactions of cumyl‐, 1‐phenylethyl‐ andtert‐butyl‐peroxy radicals withortho‐para‐substituted phenol inhibitors. The rate constants were recalculated for the same temperature. Solvent effects were neglected because the solvents used were similar in nature. The phenolorthosubstituents were characterized by an indicator variableItBuaccounting for the presence or absence ofdi‐tert‐butyl groups. The phenolparasubstituents were characterized by Charton's σI, σR, and σ R+substituent constants.The dependence of logkvalues onItbu, σI, σR, σ R+was investigated using stepwise linear regression analysis. The combined data set of 32 reactions gives:\documentclass{article}\pagestyle{empty}\begin{document}$$\log \,\,k_{(333{\rm K)}} = - 0.801\sigma _I - 2.483\sigma _{\rm R} + 3.766\,\,\,\,\,\,\,\,\,(r = 0.851)$$\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$$\log \,\,k_{(333{\rm K)}} = - 0.932\sigma _1 - 2.302\sigma _R^ + + 3.802\,\,\,\,\,\,\,\,\,(r = 0.848)$$\end{document}The results suggest that hydrogen abstraction from phenols by peroxy radicals proceeds by an electrophilic mechanism, and that neither the peroxy‐radical nor theortho‐di‐tert‐butyl groups have considerable

ISSN:0538-8066    

DOI:10.1002/kin.550211211

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY