摘要:

AbstractA computerized method is given for the evaluation of Arrhenius parameters which describe the chemiluminescent decomposition of tetramethyl‐1,2‐dioxetane. The parameters were determined in several solvents by linear regression methods and the equation ln ln\documentclass{article}\pagestyle{empty}\begin{document}$ [(\sum\nolimits_0^\infty I - \sum\nolimits_0^t I)/(\sum\nolimits_0^\infty I - \sum\nolimits_0^t I - \sum\nolimits_0^{t + \Delta t} I)] = \ln\, (A_1 \Delta t) - E_1 /RT$\end{document}, whereIrefers to photons counted by increments of Δt, andE1andAare the first‐order Arrhenius parameters. The average ofE1and logA1(s−1) from this method from six runs in CCl4with initial concentrations of 4.9 × 10−5‐8.45 × 10−4Mwere 27.21 ± 0.88 kcal/mol (113.7 ± 3.7 kJ/mol) and 13.88 ± 0.50, respectively. Simulated curves of chemiluminescence versus time were obtained with the use of a computer program and a

ISSN:0538-8066    

DOI:10.1002/kin.550131202

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe equilibrium I2(g) + 2NO(g) = 2INO(g) has been studied at room temperature by ultraviolet absorption spectroscopy. The equilibrium constant has been measured asKp= (2.7 ± 0.3) × 10−6atm−1at 298 K. Third‐law calculations lead to ΔH°f,298(INO) = 120.0 ± 0.3 kJ/mol. The relative absorption spectrum of INO has been measured between 225 and 300 nm. Quantitative measurements gave ϵ(λmax= 238 nm) = (1.79 ± 0.5) × 104L/mol·cm and ϵ(410 nm) = 234

ISSN:0538-8066    

DOI:10.1002/kin.550131203

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe rates of the reactions of hydroxyl radicals (OH) with styrene, α‐methylstyrene, and β‐methylstyrene have been measured by irradiating mixtures of these aromatic olefins and NO in an environmental chamber at 298 K. Experimental conditions were used whereby the competition of ozone with OH in oxidizing the hydrocarbons could be considered negligible. The rate constant values, obtained by a relative method using isooctane as reference hydrocarbon, are: styrene (5.3 ± 0.5) × 10−11cm3/molec·s, α‐methylstyrene (5.3 ± 0.6) × 10−11cm3/molec·s, and β‐methylstyrene (6.0 ± 0.6) × 10−11cm3/molec·s. A simplified kinetic treatment of the experimental data shows that styrene and β‐methylstyrene are stoichiometrically converted to benzaldehyde, suggesting that OH attack occurs only on the aliphatic moiety of the aromatic olefins. Benzaldehyde was observed to undergo consecutive oxidation by OH, and its maximum formation yield was about 60%. A reaction mechanism is proposed where the primary rate‐determining OH attack leads to the formation of 1‐hydroxy‐2‐phenyl‐2‐ethenyl radicals, from which benzaldehyde is f

ISSN:0538-8066    

DOI:10.1002/kin.550131204

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractRate constants for direct reactions of propylene oxide with certain aminoisopropanols in the presence of basic catalysts were studied at a temperature of 363–383 K. This reaction was found to be of the first order in propylene oxide, amino alcohol and catalyst. The observed kinetics are consistent with a termolecular mechanis

ISSN:0538-8066    

DOI:10.1002/kin.550131205

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractUltraviolet absorption spectra have been characterized for the acetyl‐h3and acetyl‐d3radicals, which were generated by the flash photolysis of the corresponding acetones. The spectra are broad and intense, with values of the extinction coefficient at the respective maxima estimated as: ϵCH3CO(215) = (1.0 ± 0.1) × 104L/mol·cm and ϵCD3CO(207.5) = (1.0 ± 0.05) × 104L/mol·cm. Rate constants for the reactions of mutual interactionwere estimated as:k 4H= 3.5 × 1010L/mol·s andk 4D= 3.4 × 1010L/mol·s. Rate constants for the reactions of cross interactionwere estimated as:k 3H= 8.6 × 1010L/mol·s andk 3D= 5.2 × 1010L/mol·s. The related values of the cross interaction ratiosk 3H/(k 2Hk 4H)1/2= 2.6 andk 3D/(k 2Dk 4D)1/2= 1.6 do not differ significantly from the statistical value of 2. The participation of the radical displacement reactionswas estimated in terms of the fractionsk 3bH/k 3H= 0.38 andk 3bD/k 3D= 0.47.Corroborative spectra were obtained from the flash photolysis of methyl ethyl ketone and biacetyl, and the relative rates of the competing primary processes were estimated from the relative peak heights o

ISSN:0538-8066    

DOI:10.1002/kin.550131206

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractAccording to our experiments the bromide ion concentration exhibits in the bromate–ascorbic acid–malonic acid–perchloric acid system three extrema as a function of time. To describe this peculiar phenomenon, the kinetics of four component reactions have been studied separately. The following rate equations were obtained:Bromate–ascorbic acid reaction:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} { - d[{\rm BrO}_3^ -]/dt = k_1 [{\rm BrO}_3][{\rm H}_2 {\rm A],}} & {k_1 = 8.3 \times 10^{ - 3} M^{ - 1} \cdot {\rm s}^{ - {\rm 1}} } \\ \end{array} $$\end{document}Bromate–bromide ion reaction:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} { - d[{\rm BrO}_3^ -]/dt = k_2 [{\rm BrO}_3][{\rm Br}^ -][{\rm H}^ +]^2,} & {k_2 = 3.6M^{ - 3} \cdot {\rm s}^{ - 1} } \\ \end{array} $$\end{document}Bromide–ascorbic acid reaction:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} { - d[{\rm Br}_{\rm 2}]/dt = k_3 [{\rm Br}_2][{\rm H}_2 {\rm A],}} & {k_3 \ge 1.7 \times 10^{ - 3} \cdot {\rm s}^{ - 1} } \\ \end{array} $$\end{document}Bromine–malonic acid reaction:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} { - d[{\rm Br}_{\rm 2}]/dt = k_4 k_4 [{\rm Br}_2][{\rm H}_2 {\rm M}]/(k_4 + k_5 [{\rm Br}_2]),} & {k_4 = 6 \times 10^{ - 3} {\rm s}^{ - 1} } \\ \end{array}, \quad {\rm }k_{ - 4} \ge 1.7 \times 10^{ - 3} \cdot {\rm s}^{ - 1} \quad {\rm }k_5 \ge 1 \times 10^7 M^{ - 1} \cdot {\rm s}^{ - 1} $$\end{document}k4= 6 × 10−3s−1,k‐4≥ 1.7 × 103s−1,k5≥ 1 × 107M−1· s−1Taking into account the stoichiometry of the component reactions and using these rate equations, the concentration versus time curves of the composite system were calculated. Although the agreement is not as good as in the case of the component reactions, it is remarkable that this kinetic structure

ISSN:0538-8066    

DOI:10.1002/kin.550131207

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe pyrolysis of 1‐iodopropane has been studied by the variable encounter method (VEM) at temperatures from 625 to 840 K. Deactivating wall collisions are found to be stronger for this molecule than for the hydrocarbons previously studied in this temperature range. The results of this study are compared with earlier steady‐state w

ISSN:0538-8066    

DOI:10.1002/kin.550131208

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractIt is shown that chain reactions may be studied in stirred‐flow reactors under conditions in which the escape of radicals from the reactor competes significantly with the chemical termination reaction. The appropriate rate law permits the independent evaluation of the rate constants of the initiation and termination steps. Such information is of special interest in the study of surface effects on chain reaction

ISSN:0538-8066    

DOI:10.1002/kin.550131209

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550131210

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550131201

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY