摘要:

AbstractReactions of the hydroxyl radical, OH, with several reactants have been studied near 1200 K in shock tube experiments in which UV absorption was used to monitor the OH concentration. The values of the rate coefficients were found to be 2.7 × 1012, 2.6 × 1012, 2.8 × 1013, and 1.26 × 1013cm3/mol‐s for the reactions of OH with hydrogen, methane, cyclopentane, and isobutane, respectively. These measured values are compared with previous experimental results and transition‐state theory calcu

ISSN:0538-8066    

DOI:10.1002/kin.550210702

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractRate constants of Br atom reactions have been determined using a relative kinetic method in a 20 l reaction chamber at total pressures between 25 and 760 torr in N2+ O2diluent over the temperature range 293–355 K. The measured rate constants for the reactions with alkynes and alkenes showed dependence upon temperature, total pressure, and the concentration of O2present in the reaction system.Values of (6.8 ± 1.4) × 10−15, (3.6 ± 0.7) × 10−14, (1.5 ± 0.3) × 10−12, (1.6 ± 0.3) × 10−13, (2.7 ± 0.5) × 10−12, (3.4 ± 0.7) × 10−12, and (7.5 ± 1.5) × 10−12(units: cm3s−1) have been obtained as rate constants for the reactions of Br with 2,2,4‐trimethylpentane, acetylene, propyne, ethene, propene, 1‐butene, andtrans‐2‐butene, respectively, in 760 torr of synthetic air at 298 K with respect to acetaldehyde as reference,k= 3.6 × 10−12cm3s−1.Formyl bromide and glyoxal were observed as primary products in the reaction of Br with acetylene in air which further react to form CO, HBr, HOBr, and H2O2. Bromoacetaldehyde was observed as an primary product in the reaction of Br with ethene. Other observed products included CO, CO2, HBr, HOBr, BrCHO,

ISSN:0538-8066    

DOI:10.1002/kin.550210703

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractA kinetic study of uncatalyzed and Ru(III) catalyzed oxidation of indigo carmine(IC) (disodium 3,3′‐dioxobi‐indolin‐2,2′‐ylidene‐5,5′‐disulphonate) by iodate ion in aqueous sulphuric acid solution is reported. The uncatalyzed reaction order was found to be four; one each with respect to IC and iodate ion and second order with H+ion. The Ru(III) catalyzed reaction was of fifth order, second order with respect to H+and first order with respect to reductant, oxidant, and catalyst. Stoichiometric ratios of both reactions were the same with a 3:2 reductant‐oxidant ratio. In both uncatalyzed and catalyzed reactions isatin‐5‐monosulphonic acid (2,3‐dioxoindoline‐5‐sulphonic acid) was observed as the oxidation product. Rate constants for both the reactions are reported. Reaction mechanisms consistent with the experimental data are suggested.Further, a fixed time method is described for the determination of Ru(III), based on its ability to catalyze the oxidation of IC by acidic iodate. Using [H+] 2.25M, [iodate] 1.00 × 10−3Mand [IC] 5.0 × 10−5M, in presence of Ru(III), the reaction followed first order kinetics with respect to IC. The interference of various cations, neutral salts, and potassium iodide on the determination of Ru(III) was studied using synthetic mixtures. The selectivity of the method and the

ISSN:0538-8066    

DOI:10.1002/kin.550210704

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe near U‐V photolysis oft‐butyl nitrite has been studied over the temperature range 303–393 K. Under these conditionst‐butyl nitrite was shown to be a very clean photochemical source oft‐butoxy radicals. This allows a study of the decomposition of thet‐butoxy radical to be made over this temperature range (3).Extrapolation of the rate constantsk3to high pressure and combination with our previous thermal data give the results:\documentclass{article}\pagestyle{empty}\begin{document}$$k_3 (\infty)/{\rm s}^{{\rm - 1}} = 10^{14.04 \pm 0.37} \exp (- 7519 \pm 70.5/T)$$\e

ISSN:0538-8066    

DOI:10.1002/kin.550210705

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractPhenol pyrolysis has been studied in a turbulent flow reactor by analyzing concentration‐time profiles of three major decomposition products: carbon monoxide, cyclopentadiene, and benzene. Experimental conditions wereP= 1 atm,T= 1064 − 1162K, and initial phenol concentrations of 500−2016 ppm. The major experimental observations were that the decomposition product profiles were nearly linear as a function of time and that the overall rate of carbon monoxide production was greater than that of cyclopentadiene. The rate difference is explained by a mechanism which includes a radical combination reaction of cyclopentadienyl and phenoxy. With literature and approximate rate coefficient data, the mechanism reproduced the experimental observations very well. The mechanism and data provide estimates of rate coefficients for the phenol decomposition initiation step, abstraction of hydrogen from phenol by cyclopentadienyl, and the phenoxy‐cyclopentadienyl combination, all of which have not been available in the lit

ISSN:0538-8066    

DOI:10.1002/kin.550210706

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractA chemical kinetic model was constructed for the pyrolysis of butylbenzene. The mechanism was based on free radical reactions. All relevant reactions were considered, and a final selection of 60 reactions involving 29 molecules and free radicals was made. The rate constants and thermodynamic parameters were taken from the literature or estimated using accepted literature methods such as group additivity. The results from the model were compared to experimental rates and product selectivity for butylbenzene pyrolysis over a temperature range of 778 K to 868 K and to an experimental rate at 923 K. The rates agreed within a factor of two and were usually much closer. The experimental and theoretical yields of the major products, styrene, ethane, toluene, and propylene, agreed within two percentage points. The agreement for seven minor products was not quite as good, with the worst case being an overprediction of the yield of allylbenzene by a factor of 2.6.

ISSN:0538-8066    

DOI:10.1002/kin.550210707

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe title reaction has been studied in a static quartz reaction vessel between 587 and 658 K at pressures between 40 and 152 torr. The dehydrochlorination is the only significant reaction and is autoaccelerated by the produced HCl. Numerical modelling indicates that the Rice‐Herzfeld mechanism, generally used for describing the pyrolysis of halogenated ethanes, has to be completed in the case of CC13CH3with additional transfer reactions converting “dead” radicals into chain carriers and vice‐versa. The numerical simulation fits the experimental results, in the absence as well as in the presence of different amounts of added HCl. The dehydrochlorination is also accelerated by the addition of CCl4, which can be explained in terms of additional elementary steps involving · CCl3

ISSN:0538-8066    

DOI:10.1002/kin.550210708

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

Abstract3‐Methylfuran has been identified as a product of the gas‐phase reaction of the OH radical with isoprene, and under simulated atmospheric conditions a formation yield of 0.044 ± 0.006 was determined. In an analogous manner, the OH radical reaction with 1,3‐butadiene formed furan with a yield of 0.039 ± 0.011. Using a relative rate method, a rate constant for the reaction of the OH radical with 3‐methylfuran of 9.35 × 10−11cm3molecule−1s−1(with an estimated overall uncertainty of ±20%) at 296 ± 2 K was also determined. These data show that 3‐methylfuran is a reactive compound which will be present in the troposphere at concentrations ⩽5% of those of

ISSN:0538-8066    

DOI:10.1002/kin.550210709

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550210701

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY