摘要:

AbstractThis article presents the kinetic of formation of pentacyano(3‐pyrazincarboxylate)ferrate(II) from pyrazincarboxylate and pentacyanoaquoferrate(II) ions in various isodielectric water‐cosolvent mixtures at 298 K. The rate law is in the formd[Fe(CN)5(3‐pzCO2)4−]/dt=

ISSN:0538-8066    

DOI:10.1002/kin.550221002

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractKietics of oxidation of phenylhydrazine andp‐bromophenylhydrazine by hexacyanoferrate(III) in acidic medium have been studied. The reactions follow similar kinetics, being first order with respect to both hydrazine and exacyanoferrate(III) and inverse first order with respect to the hydrogen ion. Addition of hexacyanoferrate(II) has no retarding effect on the rate of oxidation. The effects of varying ionic strength, dielectric constant, and temperature on the reaction rates have been investigated. A plausible mechanism has been proposed to account for the experimental results. Benzene and bromobenzene have been identified as the oxidation product

ISSN:0538-8066    

DOI:10.1002/kin.550221003

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractKinetics of oxidation of six aliphatic aldehydes by Os(VIII) in alkaline solutions have been studied. The reaction is of first order with respect to each of the aldehyde and Os(VIII). The pseudo‐first order rate constants decreased with an increase in the concentration of hydroxyl ions. The oxidation of deuterioacetaldehyde (MeCDO) exhibited a substantial primary kinetic isotope effect. Separate rate constants for the oxidation of hydrate and free aldehyde forms have been evaluated. The aldehyde hydrate is postulated as the active reductant. Ionic strength has no noticable effect on the rate. The rate‐determining step is, therefore, postulated to be a bimolecular reaction between the aldehyde hydrate and [OsO4(OH)2]−2. The value of the limiting rate constant exhibited an excellent correlation with Taft σ* values; reaction constant being negative. A mechanism involving transfer of a hydride ion from the aldehyde hydrate to Os(VIII) has been pr

ISSN:0538-8066    

DOI:10.1002/kin.550221004

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractA redetermination of the disproportionation/combination ratio forn–C3F7and C2H5radicals gives a value of Δ(n–C3F7, C2H5) = 0.13 ± 0.01, independent of the temperature. The radicals were produced by the photolysis ofn–C3F7COC2H5. The previous determinations of this ratio are discussed and are found to be largely incorrect. The values for Δ(CF3, C2H5) and Δ(C2F5, C2H5) are also re‐evaluated, and the recommended values are 0.10 ± 0.02 and 0.12 ± 0.02, respectively. Systems involving perfluoroalkyl and ethyl radicals are complicated due to rapid perfluororadical addition to the ethylene formed in the disproportionation process. The extent of this reaction, and its consequences, are discussed and evaluated. The role of the propionyl (C2H5CO) radical in the room temperature photolysis is also assessed. However, it is found that the Δ values determined by the intercept method used in this work are not affected by the secondary reactions that occur. It is concluded that high cross‐combination ratios are general to perfluoroalkyl‐alkyl radical interactions. For C3F7and C2H5radicals the ratio is 2.7–2.8. Above 100°C ratios exceed 3 due t

ISSN:0538-8066    

DOI:10.1002/kin.550221005

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe reactions of naphthalene in N2O5NO3NO2N2O2reactant mixtures have been investigated over the temperature range 272–297 K at ca. 745 torr total pressure and at 272 K and ca. 65 torr total pressure using long pathlength Fourier transform infrared absorption spectroscopy. 2,3‐Dimethyl‐2‐butene was added to the reactant mixtures at 272 K to rapidly scavenge the NO3radicals both initially present in the added N2O5and formed from the thermal decomposition of N2O5during the reactions. The data obtained in the presence and absence of added 2,3‐dimethyl‐2‐butene showed that napthalene undergoes initial reaction with the NO3radical to form an NO3‐naphthalene adduct, which either rapidly decomposes back to the reactants (at a rate of ca. 5 × 105s−1at 298 K) or reacts exclusively with NO2to form products. When NO3radicals, N2O5and NO2are in equilibrium, this overall process is kinetically equivalent to reaction of naphthalene with N2O5, and previous kinetic and product studies have indeed assumed the reactions of naphthalene and alkyl‐substituted naphthalenes in N2O5NO3NO2air mixtures to be w

ISSN:0538-8066    

DOI:10.1002/kin.550221006

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractA laser flash photolysis‐long path laser absorption technique has been employed to investigate the kinetics of NO3reactions with CH3SCH3(

ISSN:0538-8066    

DOI:10.1002/kin.550221007

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractKinetic and mechanistic investigations of liquid phase autoxidation of hexadecane at 120 to 190°C have shown that, in the early stages of oxidation, the initiation process involves homolytic decomposition of hydroperoxides. The values of a composite first order rate constant for this decomposition,

ISSN:0538-8066    

DOI:10.1002/kin.550221008

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550221001

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY