摘要:

Abstract1,1‐Dichlorocyclopropane has been produced by addition of CH2(1A1) to 1,1‐dichloroethylene. CH2(1A1) was generated by the photolysis of ketene at 277–334 nm. The 1,1‐dichlorocyclopropane was formed in a chemically activated state, had an energy content between 386 and 400 kJ/mol, and reacted in two parallel channels to 2,3‐dichloropropene and 1,1‐dichloropropene. 1,1‐Dichloropropene was also formed directly by insertion of CH2(1A1) into the CH bond of 1,1‐dichloroethylene. As secondary reactions elimination of HCl from chemically activated 2,3‐dichloropropene occurred with 3‐chloropropyne and chloroallene as products. In some of the experiments perfluoropropane was added as an inert gas. The apparent rate constants for the isomerization and elimination reactions are reported. The results of RRKM calculations including distribution functions for the activated 1,1‐dichlorocyclopropane and a step‐ladder model for the deactivation verify the p

ISSN:0538-8066    

DOI:10.1002/kin.550131102

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractIn a crossed laser–molecular beam study of nitromethane it was found that the excitation of nitromethane at 266 nm did not yield dissociation products under collision‐free conditions. When a small cluster of nitromethane was excited at the same frequency, the product was seen only at energies and masses consistent with the rupture of the van der Waals bond by vibrational predissociation of the excited st

ISSN:0538-8066    

DOI:10.1002/kin.550131103

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractRate constants for the gas‐phase reactions of O3with the carbonyls acrolein, crotonaldehyde, methacrolein, methylvinylketone, 3‐penten‐2‐one, 2‐cyclohexen‐1‐one, acetaldehyde, and methylglyoxal have been determined at 296 ± 2 K. The rate constants ranged from<6 × 10−21cm3molecule−1s−1for acetaldehyde to 2.13 × 10−17cm3molecule−1s−1for 3‐penten‐2‐one. The substituent effects of CHO and CH3CO groups on the rate constants are assessed and discussed, as are implications for the atmospheric chemist

ISSN:0538-8066    

DOI:10.1002/kin.550131104

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractKinetic equations for the decay of the free radicals in polymeric solids are given for the following assumptions on which they are based: (1) two simultaneous first‐order but physically separated decay reactions; (2) two simultaneous noninteracting second‐order decay reactions; (3) combined simultaneous but intermingled first‐ and second‐order decay reactions; (4) the same but for independent, i.e., not intermingled, first‐ and second‐order decay reactions; (5) a second‐order decay reaction in the presence of some free radicals that do not decay; and (6) a first‐order decay reaction in the presence of some free radicals that do not decay. In all of the above physical systems the total concentration only can be measured. Hence the above kinetic equations refer to the change of the total concentration with time. It is found that the data for the decay of the free radicals in irradiated isotactic polypropylene and 61% styrene‐39% butadiene block copolymer agree best with the equations for the second‐order decay in the presence of a fraction of nondec

ISSN:0538-8066    

DOI:10.1002/kin.550131105

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe title reaction was studied in a stirred‐flow reactor at six temperatures ranging from 228 to 297 K and for pressures near 2 torr. The experiments were performed under O‐atom‐rich conditions, and the HOONO2concentration was monitored with a modulated molecular‐beam mass spectrometer. O‐atom concentrations were measured by titration with NO2and by monitoring the portion of O2dissociated in the microwave discharge. A weighted least‐squares analysis gives (k± 1σ) = (7.0 ± 12.2) × 10−11exp(‐3369 ± 489/T) cm3/s, where the uncertainties are 1 standard deviation (six temperatures) the covariance was σAB= 5.97 × 10−8. Due to the possible presence of systematic errors, the uncertainty in the rate constant could be as great as a factor of 2 over the

ISSN:0538-8066    

DOI:10.1002/kin.550131106

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe absolute reaction rate constant of the title reaction was measured in a stirred‐flow reactor under H‐atom‐rich conditions at seven temperatures from 226 to 315 K. Carbon monoxide was added to convert any OH radicals produced back to H atom by way of the reaction OH + CO → H + CO2. The reaction rate constants were essentially constant between 248 and 315 K: (k± 2σ) = (2.46 ± 0.35) × 10−14cm3/s. At temperatures lower than 248 K, the measured rate constant became larger at lower temperatures, possibly due to heterogeneous effects. An hypothesis is advanced that may explain the surprisingly slow rate constant that is virtually independent of temperature, but more experiments are required to determine the dynamical rea

ISSN:0538-8066    

DOI:10.1002/kin.550131107

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe sensitivity of the period of the Belousov–Zhabotinsky oscillations to the rate constants and initial conditions of our previously proposed mechanism is computed by the technique recently developed for this purpose and shown to be valid in our analysis of the Oregonator. The principal rate‐controlling steps for the determination of the period are found to be the enolization and bromination of malonic acid. Dependence of the period on initial conditions qualitatively agrees with available experimental data, except for the hydrogen ion, where a large discrepancy exists. It is suggested that this may be due to deficiencies in the organic reactions in the mechanism, or to a hydrogen‐ion catalyzed bromination mechanism for malonic acid. Other components of the mechanism, which participate in characterizing the period and amplitude of the oscillations, are disc

ISSN:0538-8066    

DOI:10.1002/kin.550131108

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractA general mechanism was proposed for the title reactions which describes the kinetics of hydroperoxide decomposition as well as product accumulation throughout the whole reaction period in an analytical form. The following catalytic steps were included:where the deactivation takes place as a result of radical–catalyst interaction inside the cage. The resulting equations give satisfactory description of the literature data in the case of various catalysts and hydroperoxide

ISSN:0538-8066    

DOI:10.1002/kin.550131109

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe kinetics of the aquation of (H2O)5Cr(O2CCCl3)2+have been examined at 35–55°C and 1.00Mionic strength with [H+] = 0.01−1.00M.The reaction follows the rate equation ‐dln [Crtotal]/dt= (a[H+]−1+b+c[H+])/(1 +d[H+]), where [Crtotal] is the stoichiometric concentration of the complex. At 45°Ca= (1.41 ± 0.03) × 10−7M/s,b= (1.66 ± 0.02) × 10−5s−1,c= (7.0 ± 0.8) × 10−5M−1·S−1andd= 2.3 ± 0.3M−1. Two mechanisms consistent with this rate law are discussed, with evidence being presented in favor of an ester hydrolysis mechanism involving steady‐state intermediates. Equilibrium and acti

ISSN:0538-8066    

DOI:10.1002/kin.550131110

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550131111

出版商:John Wiley&Sons, Inc.    

年代:1981

数据来源: WILEY