摘要:

AbstractThermochemical analysis of the electron capture process of SF6leads to a rate constant for the reverse process\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm SF}_6^ - \mathop \to \limits^2 {\rm SF}_6 + e^ -,k_2 = 1.5 \times 10^{13 - 31.4/\theta } {\rm s}^{{\rm - 1}} $\end{document}, where θ = 2.303RT, in kcal/mol. The electron affinity of 32±3 kcal/mol is deduced from the observed bimolecularity of the capture process down to 0.1 torr Ar bath gas and estimated entropies of SF6and SF 6−. The capture process is discussed from the view point of the formation of a metastable SF 6−electron (SF6·e L−) Langevin complex which appears to have a lifetime of about 2 × 10−13s. Curve crossing from the SF6·e L−complex to vibrationally excited (SF 6−)* appears to have a normal rate andAfactor. This is interpreted to indicate near‐resonant coupling between the orbiting electron and the vibronic motions of SF6, together with similarity in structure of SF6and SF 6−. It is shown that the apparent slowness of thermal electron ejection from SF 6−is a result of an unfavorable equilibr

ISSN:0538-8066    

DOI:10.1002/kin.550150202

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractAn empirical approach to the kinetic investigations of photo‐initiated liquid‐phase chlorination of benzene is presented. Reaction order and the reaction constants for chlorine consumption and for the production of hexachlorocyclohexane isomers were evaluated from experimental d

ISSN:0538-8066    

DOI:10.1002/kin.550150203

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe kinetics of oxidation of methyl phenyl sulfoxide by chloramine‐T (CAT) has been studied in buffered ethanol–water (1:1 v/v) of pH 7.0. The reaction was found to follow no simple‐order kinetics. A possible mechanism is suggested involving three rate‐controlling steps: (1) the reaction between RNHCl (R = CH3C6H4SO2) and the sulfoxide, (2) the disproportionation of RNHCl, and (3) the reaction between RNCl2and the sulfoxide. A mixed‐order rate law is derived as rate/[C][SO]=k1+Kdk2[C]/[SA]. The rate law is found to be obeyed for the meta‐ and para‐substituted phenyl methyl sulfoxides also. The ρ value is obtained using Hammett's σ constants. The ρ values obtained for the attack of both RNHCl and RNCl2with the sulfoxides are almost the same, showing that both are converting the sulfoxide to the same intermediate. A chlorinium ion trans

ISSN:0538-8066    

DOI:10.1002/kin.550150204

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe vacuum decomposition of sucrose and cellobiose has been observed in the 150–250°C temperature range. The predominant decomposition product of both sugars is H2O with less than 5% CO, CO2, CH2O, CH3CHO, CH3OH, and C2H5OH formed. The detailed rates and temperature dependences suggest that with the possible exception of C2H5OH, the minor products are formed in secondary reactions of the dehydration products. Further it is shown that the so‐called “melting with decomposition” of a sugar is in reality a high‐temperature dissolution of the disaccharide in the elimin

ISSN:0538-8066    

DOI:10.1002/kin.550150205

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractVibrationally excited OH inv= 9 [designated OH†(9)] was generated by the reaction of hydrogen atoms with ozone in a fast‐flow discharge system at 300 ± 3 K and a total pressure of 1.1 ± 0.1 torr, with argon as the carrier gas. The addition of a species X, which can deactivate the OH†(9) or react with it, led to a decrease in the Meinel band chemiluminescent emission intensities at both 626 nm (9 → 3 band) and 519 nm (9 → 2 band), which were monitored as a function of the concentration of X. Application of the kinetic scheme developed previously for this chemical system gave the relative rate constant for the removal of OH†(9) by X. The relative rate constants determined in this study, taking O2as the reference deactivator (k O 2= 1.0), are as follows: He ≤ 0.02; H2≤ 0.05; SF60.09 ± 0.01; CF40.19 ± 0.01; N2O 3.5 ± 0.4; NO 17.7 ± 1.5; H2O 74.3 ± 2.9; D2O 57.6 ± 2.0; NH361.3 ± 1.9; ND358.7 ± 1.6; SO27.1 ± 1.4; COS 8.4 ± 1.7; H2S 33.7 ± 8.4; CH41.56 ± 0.03; CD41.06 ± 0.06. Application of these relative rate constants to conditions in the upper atmosphere (60–100 km) suggests that OH†(9) is removed primarily by deactivation by O2, and at altitudes ≳90 km, possibly by O(3P). However, since O2is unusually efficient for a homonuclear diatomic in deactivating OH†(9), it may not be the primary deactivator for the lower (v≤ 8) vibrational levels. These results are compared to earlier studies of OH†(9), and possible mechanisms of interactio

ISSN:0538-8066    

DOI:10.1002/kin.550150206

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe bond dissociation energies of tetramethyl germane, triethyl stibine, tetraethyl lead, and triethylphosphine were determined using the technique of very‐low‐pressure pyrolysis. Arguments are presented for logA≥ 17.0. The respective dissociation energies ΔH298are 83, 57, 54, and 68 (±2) kcal/mol. A consistent set of methyl bond energies to main group metals is determined from these and previous results, and is examined for trends. Bond energies for various radicals to tin are also

ISSN:0538-8066    

DOI:10.1002/kin.550150207

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe reaction of C2F5radicals with HCN has been studied over the range of 533–673 K using the pyrolysis of pentafluoroethyl iodide as the free‐radical source. Arrhenius parameters for the reactionrelative to C4F10recombination are given by\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k_{\rm H} /k_{c^{1/2} } = (5.36 \pm 0.15) - (57.3 \pm 1.8)/\theta $$\end{document}where θ = 2.303RTkJ/mol andkH/k c 1/2is in cm3/2/mol

ISSN:0538-8066    

DOI:10.1002/kin.550150208

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe oxidation of naphthols by alkaline hexacyanoferrate(III), at constant ionic strength, gave coupled products. The rate of the reaction was dependent on the first powers of the concentrations of substrate, oxidant, and alkali. The activation energies were 31.8 and 34.5 kJ/mol for α naphthol and β naphthol, respectively. The reaction pathway was via the formation of a radical intermediate, which was detected by electron spin resonance spectroscop

ISSN:0538-8066    

DOI:10.1002/kin.550150209

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550150201

出版商:John Wiley&Sons, Inc.    

年代:1983

数据来源: WILEY