摘要:

AbstractThe thermal decomposition of CCl3O2NO2,CCl2FO2NO2, and CClF2O2NO2was studied in a temperature‐controlled 420 l reaction chamber usingin situdetection of peroxynitrates by long‐path IR absorption. The temperature dependence of the unimolecular dissociation rate constants was determined at total pressures of 10 and 800 mbar in nitrogen as buffer gas, and the pressure dependence was measured at 273 K between 10 and 800 mbar. In Troe's notation, the data are represented by the following values for the limiting low and high pressure rate constantsk0/[N2] andk∞and the fall‐off curvature parameterFc(in units of cm3molecule−1s−1, s−1): CCl3O2NO2,k0/[N2] = 6.3 × 10−3exp(−85.1 kJ · mol−1/RT),k∞= 4.8 × 1016exp(−98.3 kJ · mol−1/RT),Fc= 0.22; CCl2FO2NO2,k0/[N2] = 1.01× 10−2exp(−90.3 kJ · mol−1/RT),k∞= 6.6 × 1016exp(−101.8 kJ · mol−1/RT),Fc= 0.28; and CClF2O2NO2,k0/[N2] = 1.80 × 10−3exp(−87.3 kJ · mol−1/RT),k∞= 1.60 × 1016exp(−99.7 kJ · mol−1/RT),Fc= 0.30. From these dissociation rate constants and recently measured rate constants for the reverse reaction (see Caralp, Lesclaux, Rayez, Rayez, and Forst [19]), bond energies (=ΔH r,00) of 100, 103, and 104 kJ/mol were derived for the RO2–NO2bonds in CCl3O2NO2, CCl2FO2NO2, and CClF2O2NO2, respectively. The kinetic and thermochemical parameters of these decomposition reactions are compared with those of the dissociation of other peroxynitrates. Atmospheric implications of the thermal st

ISSN:0538-8066    

DOI:10.1002/kin.550230102

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractKinetics of the sulfuric acid catalyzed esterification of palmitic acid with isobutyl alcohol has been studied and reviewed critically. A theoretical rate equation is derived by the following reaction mechanism: (1) The reaction of sulfuric acid and isobutyl alcohol produces isobutyl sulfuric acid which acts as a catalyst; (2) Palmitic acid is protonated by the catalyst to form the reaction intermediate; and (3) The esterification proceeds reversibly. The experimental results are consistent with this rate equation.

ISSN:0538-8066    

DOI:10.1002/kin.550230103

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractKinetics of oxidation of indigo carmine (IC) by sodium hypohalites, NaOX (X  Cl or Br), in alkaline buffer of pH 9–11 has been studied spectrophotometrically at λ = 610 nm. The experimental rate law obtained is −d[IC]/dt=k[OX−][IC][OH−]xwherex<1. Variation of ionic strength or dielectric constant of the medium had no effect on the reaction rate while the addition of halide ions slightly retarded the rate. A most plausible mechanism proposed on the basis of experimental results involves the formation of isatin sulphonate which undergoes further oxidation to anthranilate. Activation parameters have been

ISSN:0538-8066    

DOI:10.1002/kin.550230104

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe overall rate coefficientkof the self recombination of BrO radicals has been measured at 298 K with use of the discharge flow/mass spectrometry technique. The rate coefficientk2for the reaction channel forming Br2has been also determined. The results are:k= (3.2 ± 0.5) × 10−12andk2= (4.7 ± 1.5) × 10−13(in cm3molecule−1s−1). These results are discussed with respect to previous lite

ISSN:0538-8066    

DOI:10.1002/kin.550230105

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe photolysis of C2F5I with CF3COOH in the temperature range 473–533 K was studied in the gas phase.Evidence is presented that supports a complex mechanism for the formation of C2F5H through the H‐atom abstraction reaction from CF3COOH by C2F5radicals as well as the participation of I(2

ISSN:0538-8066    

DOI:10.1002/kin.550230106

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractWe have studied the effect of vibrational mode activation in the CF3radical on the bromine abstraction reaction; CF3+ Br2→ CF3Br + Br. Excess vibrational energy resides in the symmetric modes of the radical after 248 nm photolysis of the parent molecule, CF3I. Our data indicate that the hot radicals react no faster than thermalized CF3, and may actually have a lower cross‐section for reaction. Dynamical factors that result in poor coupling of the vibrational energy to the reaction coordinate, as well as other similar considerations, could be responsible for the experimental observations. In addition, we have made an independent determination of the rate for the bromine abstraction reaction of (1.08 ± .13) × 1012s−1c

ISSN:0538-8066    

DOI:10.1002/kin.550230107

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ring‐retaining products formed from the OH radical‐initiated reactions ofo‐,m‐, andp‐xylene in the presence of NOxhave been identified and their formation yields determined. Experiments were carried out at 298 ± 2 K and in the presence of 740 torr total pressure of air. The products observed, and their yields, were: fromo‐xylene,o‐tolualdehyde, 0.0453; 2‐methylbenzyl nitrate, (0.0135 + 5.5 × 10−17[NO2]); 2,3‐dimethylphenol, 0.097; 3,4‐dimethyl‐phenol, 0.064; 3‐nitro‐o‐xylene, 0.0059; 4‐nitro‐o‐xylene, (0.0111 + 9.9 × 10−17[NO2]); fromm‐xylene,m‐tolualdehyde, 0.0331; 3‐methylbenzyl nitrate, 0.0061; 2,4‐dimethylphenol, 0.099; 2,6‐dimethylphenol, 0.111; 4‐nitro‐m‐xylene, 0.0018; 5‐nitro‐m‐xylene, (0.0032 + 1.6 × 10−17[NO2]); fromp‐xylene,p‐tolualdehyde, 0.0701; 4‐methylbenzyl nitrate, 0.0082; 2,5‐dimethylphenol, 0.188, 2‐nitro‐p‐xylene, (0.0120 + 2.8 × 10−17[NO2]), where the NO2concentration is in molecule cm−3units. The nitro‐xylene data are consistent with our recent product study of the corresponding reactions of benzene and toluene and indicate that under the experimental conditions employed the dimethylhydroxycyclohexadienyl radicals reacted with NO2and not with O2. When combined with literature ring‐cleavage pr

ISSN:0538-8066    

DOI:10.1002/kin.550230108

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractIt is reported and explained that the front‐like reaction sustains, and its velocity is enhanced in frozen phase in the chlorite‐thiosulphate sys

ISSN:0538-8066    

DOI:10.1002/kin.550230109

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550230110

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550230101

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY