摘要:

AbstractThe stopped‐flow technique has been used to study the effect of cationic (CTAN), nonionic (Triton X‐100), andanionic (SDS) micelles on the rate of the reaction between nickel(II) ion and the ligand pyridine‐2‐azo‐p‐dimethylaniline (PADA) at 20.0°C and ionic strength 0.03 mol dm−3. The complex formation reaction is markedly inhibited by both CTAN and Triton X‐100 micelles. The kinetic dataare found to conform to a reaction mechanism which implies only partitioning of the ligand between water and the micellar phase, the estimated bindingconstant of PADA being significantly larger in the presence of CTAN aggregates. Anionic micelles strongly speed the complexation reaction, Which occurs in the micellar phase with the same rate and the same mechanism as in water. The extent of binding of PADA to anionic micelles is similar to that found for the cationic mic

ISSN:0538-8066    

DOI:10.1002/kin.550180602

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractUnimolecular reactions of mutual isomerization of cyclopentyl and 1‐penten‐5‐yl radicals have been investigated by chemical activation. The radicals were generated by adding energized hydrogen atoms (EHabout 23 kcal mol−1) to the double bond of either cyclopentane or 1,4‐pentadiene. Based on the extensive steady‐state RRKM calculations employing the experimental data from this work as well as from the literature, the threshold energies for the cyclopentyl ring opening and closure are 32 ± 0.3 and 16.2 ± 0.3 kcal mol−1, respectively. The entropy of activation for the ring opening i

ISSN:0538-8066    

DOI:10.1002/1097-4601(198606)18:6<623::AID-KIN550180603>3.0.CO;2-7

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractGaseous haloalkyl radicals were prepared by the photolysis of iodohaloalkanes in Pyrex vessels containing mercury (I) halides. Cleavage of the carbon‐iodine bond gave mercury (II) halide and a radical which was subsequently shown to react on the ground state electronic energy surface. The usefulness of this method for chemical activation rate constant studies is illustrated by measurement of unimolecular rate constants for decomposition of CH2ClCH2Cl and CF3CH3. Possible mechanisms for photodecomposition of iodoalkanes in the presence of mercury (I) halides are discusse

ISSN:0538-8066    

DOI:10.1002/1097-4601(198606)18:6<639::AID-KIN550180604>3.0.CO;2-M

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550180605

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractAcetaldehyde oxidation has been studied in experiments at temperatures of 553 and 713 K carried out in a low pressure, static reactor and in numerical modeling calculations using a detailed chemical kinetic reaction mechanism. The results of the experimental study were used to construct and validate the reaction mechanism, which was then used to examine acetaldehydeoxidation in the negative temperature coefficient regime between 550 and 900 K. This mechanism was also tested against independent measurements of acetaldehyde oxidation carried out by Baldwin, Matchan, and Walker. The overall rate of reaction and the properties of the negative temperature coefficient regime were found to be sensitive to the competition between radical decomposition reactions and the addition of molecular oxygen to acetyl and methyl radicals, including particularly\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm CH}_{\rm 3} + {\rm O}_2 + {\rm M = CH}_{\rm 3} {\rm O}_{\rm 2} + {\rm M} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm CH}_{\rm 3} {\rm CO} + {\rm M = CH}_{\rm 3} {\rm + CO} + {\rm M} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm CH}_{\rm 3} {\rm CO} + {\rm O}_{\rm 2} {\rm = CH}_{\rm 3} {\rm CO}_{\rm 3} $$\end{document}During these experiments, an upper limit to the rate of decomposition ofCH3O2H was measured at 553 K. Implications of the results for future kinetic modeling of engine knock are discussed.

ISSN:0538-8066    

DOI:10.1002/kin.550180606

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe oxidation of primary alcohols by sodium N‐chloroethylcarbamate in acid solution, results in the formation of corresponding aldehydes. The reaction is first order with respect to the oxidant and alcohol. The rate increases with an increase in acidity. The oxidation of α,α‐dideuterioethanol exhibited a primary kinetic isotope,kH/kD= 2.11 at 298 K. The value of solvent isotope effectk(H2O)/k(D2O) = 2.23 at 298 K. Addition of ethyl carbamate does not affect the rate. (EtOC(OH)NHCl)+has been postulated as the reactive species. Plots of (logk2+ Ho) against (Ho + log[H+]) are linear with the slope, ϕ, having values from 1.78–1.87. This suggested a proton abstraction by water in the rate‐determining step. The rates of oxidation of alcohols bearing both electron‐withdrawing and electron‐donating groups are more than that of methanol. A concerted mechanism involving transfer of a hydride ion from the CH bond of the alcohol tothe oxidant and removal of a proton from the OH group by a water molecule

ISSN:0538-8066    

DOI:10.1002/kin.550180607

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractAcetylene and vinylacetylene mixtures were pyrolyzed at 400‐500°C in the absence and presence of O2or NO. The major product of the interaction between C2H2and C4H4is polymer, but benzene is also produced. Both the C2H2removal and C6H6formation rates arefirst‐order in C2H2and C4H4. The rate coefficients are\documentclass{article}\pagestyle{empty}\begin{document}$$ \log (k\{ {\rm C}_{\rm 2} {\rm H}_{\rm 2} \}, M^{ - 1} {\rm s}^{{\rm - 1}}) = 6.26 \pm 0.20 - (70.6 \pm 3.6)/2.3RT $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ \log (k\{ {\rm C}_{\rm 6} {\rm H}_{\rm 6} \}, M^{ - 1} {\rm s}^{{\rm - 1}}) = 8.65 \pm 0.39 - (125.9 \pm 5.4)/2.3RT $$\end{document}where R is the ideal gas constant in kJ/mol‐K. Benzene formation occurs by two processes: a concerted molecular mechanism (≃60%) and a singlet diradical mechanis

ISSN:0538-8066    

DOI:10.1002/kin.550180608

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550180609

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550180601

出版商:John Wiley&Sons, Inc.    

年代:1986

数据来源: WILEY