摘要:

AbstractEarlier work on the reactions of O(3P) atoms with HCl and HBr has been extended by measuring rate constants forA flow‐tube method was used with chemiluminescent monitoring of the removal of atomic oxygen. Rate constants were measured at temperatures between 340 and 489 K for (2a) and 295 and 419 K for (2b); they can be matched by the Arrhenius expressions:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_{2a} = 3.7(\pm 0.9) \times 10^{- 12} \exp \left({\frac{{- (7.0 \pm 0.5kcal/mole)}}{{RT}}} \right) $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ k_{2b} = 5.8(\pm 0.5) \times 10^{- 12} \exp \left({\frac{{- (3.5 \pm 0.2kcal/mole)}}{{RT}}} \right) $$\end{document}where the units are cm3molecule−1sec−1and the errors correspond to a single standard deviation. The results of a quasiclassical trajectory study of collisions of O(3P) with HCl (v= 0,1, and 2) and DCl (v= 0,1, and 2) are also reported. These strengthen the conclusion that, although the rates of reactions (1a) and (2a) are selectively enhanced by vibrationally exciting HCl or DCl, molecules with 0

ISSN:0538-8066    

DOI:10.1002/kin.550100102

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe rate constant for the reaction\documentclass{article}\pagestyle{empty}\begin{document}${\rm Cl} + {\rm CH}_4 \mathop {\longrightarrow}\limits^1 {\rm CH}_3 + {\rm HCl}$\end{document}has been determined over the temperature range of 200°–500°K using a discharge flow system with resonance fluorescence detection of atomic chlorine under conditions of large excess CH4. For 300°>T>200°K the data are best fitted to the expressionk1= (8.2 ± 0.6) × 10−12exp[−(1320 ± 20)/T] cm3/sec. Curvature is observed in the Arrhenius plot such that the effective activation energy increases from 2.6 kcal/mol at 200°

ISSN:0538-8066    

DOI:10.1002/kin.550100103

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe flash photolysis–vacuum ultraviolet kinetic absorption spectroscopy technique has been used to measure the absolute rate constant for the reaction of ground state S(3P) atoms withnitric oxide,\documentclass{article}\pagestyle{empty}\begin{document}${\rm S}\left({^{\rm 3} P} \right) + {\rm NO}\mathop {\longrightarrow}\limits^{\rm M} {\rm SNO}\left({{\rm M} = {\rm CO}_2} \right)$\end{document}as a function of nitric oxide concentration and total pressure. The rateconstant was determined to be 1.9±0.1 × 101112/mol2.sec at 298°K, with a high‐pressure limit of 9.3 ± 2.1×109l/mol·sec−1. The observed kinetics are consistent with a termolecular energy transfe

ISSN:0538-8066    

DOI:10.1002/kin.550100104

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractTertiary‐amyl amine has been decomposed in single‐pulse shock‐tube experiments. Rate expressions for several of the important primary steps are\documentclass{article}\pagestyle{empty}\begin{document}$$ k(t{\rm C}_5 {\rm H}_{11 - {\rm NH}_2} \to t{\rm C}_5 {\rm H}_{11}\!\!\cdot + {\rm NH}_2\cdot) = 10^{15.9} \exp (-39,700/T)\sec ^{- 1} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm C}_2 {\rm H}_5- {\rm C}({\rm CH}_3)_2{\rm NH}_2 \to {\rm C}_2 {\rm H}_5 \cdot + \cdot{\rm C}({\rm CH}_3)_2{\rm NH}_2) = 10^{16.5} \exp (- 38,500/T)\sec ^{- 1} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ k(t{\rm C}_5 {\rm H}_{11} {\rm NH}_2 \to {\rm C}_5 {\rm H}_{10} + {\rm NH}_3) <10^{14.5} \exp (- 37,200/T)\sec ^{- 1} $$\end{document}This leads toD(CH3H) –D(NH2H) = −10.5 kJ andD[(CH3)3CH] –D[(CH3)2NH2CH] = + 6 kJ.The present and earlier comparative rate single‐pulse shock‐tube data when combined with high‐pressure hydrazine decomposition results‐(after correcting for fall off effects through RRKM calculations) gives\documentclass{article}\pagestyle{empty}\begin{document}$$ [k_r^2 (t{\rm C}_5 {\rm H}_{11} \cdot,{\rm NH}_2 \cdot)/k_r (t{\rm C}_5 {\rm H}_{11} \cdot,t{\rm C}_5 {\rm H}_{11} \cdot)k_r ({\rm NH}_2 \cdot,{\rm NH}_2 \cdot)]^{1/2} \sim 2\,{\rm at}\,1100^o {\rm K} $$\end{document}wherekr(…) is the recombination rate involving the appropriate radicals. This suggests that in this context amino radical behavior is analogous to that of alkyl radicals. If this agreement is exact, then\documentclass{article}\pagestyle{empty}\begin{document}$$ k_\infty ({\rm N}_2 {\rm H}_4 \to 2{\rm NH}_2 \cdot) = 10^{16.25} \exp (- 32,300/T)\sec ^{- 1} $$\end{document}Rate expressions for the primary step in the decomposition of a variety of primary amines have been computed. In the case of benzyl amine where data exist the agreement is satisfactory. The following differences in bond energies have been estimated:\documentclass{article}\pagestyle{empty}\begin{document}$$ D(i{\rm C}_3 {\rm H}_7 {-\!-} {\rm H}) {-\!-} D[{\rm CH}_3 ({\rm NH}_2){\rm CH} {-\!-} {\rm H}] = 14.3\,{\rm kJ} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ D({\rm C}_2 {\rm H}_5 {-\!-} {\rm H}) - D({\rm NH}_2 {\rm CH}_2 {-\!-} {\rm H}) = 1

ISSN:0538-8066    

DOI:10.1002/kin.550100105

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractMixtures of N2O, H2, O2, and trace amounts of NO and NO2were photolyzed at 213.9 nm, at 245°–328°K, and at about 1 atm total pressure (mostly H2). HO2radicals are produced from the photolysis and they react as follows:Reaction (1b) is unimportant under all of our reaction conditions. Reaction (1a) was studied in competition with reaction (3) from which it was found thatk1a/k31/2= 6.4 × 10−6exp { z−(1400 ± 500)/RT} cm3/2/sec1/2. Ifk3is taken to be 3.3 × 10−12cm3/sec independent of temperature,k1a= 1.2 × 10−11exp {−(1400 ± 500)/RT} cm3/sec. Reaction (2a) is negligible compared to reaction (2b) under all of our reaction conditions. The ratiok2b/k1= 0.61 ± 0.15 at 245°K. Using the Arrhenius expression fork1agiven above leads tok2b= 4.2 × 10−13cm3/sec, which is assumed to be independent of temperature. The intermediate HO2NO2is unstable and induces the dark oxidation of NO through reaction (−2b), which was found to have a rate coefficientk−2b= 6 × 1017exp {−26,000/RT} sec−1based on the value ofk1agiven above. The intermediate can also decompose viaReaction (10b) is

ISSN:0538-8066    

DOI:10.1002/kin.550100106

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractQuantitative analysis of the products formed in 1,1′‐azoisobutane pyrolyses in the temperature range of 553°–602°K has shown that the major reactions of the iso‐butyl radical areAnalysis of initial rate data gave log10k4/(kc)1/2(cm−3/2.mol1/2.sec−1/2) = 7.54±0.44 − (136.5 + 4.8) kJ/mol/2.303RT, the Arrhenius parameters obtained being in good agreement with thermodynamic data for reaction (4). Measured values ofka/(kc)1/2wherekais the rate constant of the reactioniC4H9+ AIB →iC4H10+. AIB were consistent with published parameters determined by photolysis of 1,1′‐azoisobutane. Combination of photolysis and pyrolysis data gave log10ka/(kc)1/2(cm3/2.mol−1/22.sec−1/2) = 3.68 ± 0.15 − (27.2 ± 1.2) kJ/mol/2.303RT. The crosscombination ratio for methyl and iso‐butyl radicals has been found to be 0.25, indicating that the geometric mean rule does not hold f

ISSN:0538-8066    

DOI:10.1002/kin.550100107

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe title reaction has been investigated in the temperature range 667–715K. The only reaction products were trifluorosilyl iodide and hydrogen iodide. The rate law\documentclass{article}\pagestyle{empty}\begin{document}$$ - \frac{{d\left[{{\rm I}_2} \right]}}{{dt}} = \frac{{k\left[{{\rm I}_2} \right]^{1/2} \left[{{\rm F}_3 {\rm SiH}} \right]}}{{1 + k\prime \left[{{\rm HI}} \right]/\left[{{\rm I}_2} \right]}} $$\end{document}was obeyed over a wide range of iodine and trifluorosilane pressures. This expression is consistent with an iodine atom abstraction mechanism and for the step\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm I}^ \cdot + {\rm F}_3 {\rm SiH}\mathop {\longrightarrow}\limits^1 {\rm F}_3 {\rm Si}^\cdot + {\rm HI} $$\end{document}logk1(dm3/mol·sec) = (11.54 ± 0.17) − (130.5 ± 2.2 kJ/mol)/RTIn 10 has been deduced. From this the bond dissociation energyD(F3SiH) = (419 ± 5) kJ/mol (100.1 kcal/mol) is obtained. The kinetic andthermochemical implications of this value are

ISSN:0538-8066    

DOI:10.1002/kin.550100108

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe thermal decomposition of F5SOOSF5, P, in the presence of CO has been investigated between 130.1° and 161.9°C at total pressures between 50 and 600 torr. The reaction is homogeneous, and the only final products formed are CO2and S2F10. The rate of reaction is proportional to the pressure of P. The partial pressures of CO and O2and the total pressure have no influence on the course of reaction:\documentclass{article}\pagestyle{empty}\begin{document}$$ - \frac{{d\left[P \right]}}{{dt}} = k\left[P \right] $$\end{document}The results are explained by the following mechanis

ISSN:0538-8066    

DOI:10.1002/kin.550100109

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe unimolecularity of the thermal dehydrogenation of cyclopentene has been confirmed using the technique of very low‐pressure pyrolysis (VLPP). Application of RRKM theory shows that the experimental unimolecular rate constants obtained over the temperature range of 942°–1152°K are consistent with the high‐pressure Arrhenius parameters given by\documentclass{article}\pagestyle{empty}\begin{document}$$ \log (k/\sec ^{-1}) = 13.35 - 61/\theta $$\end{document}where θ = 2.303RTkcal/mol. These parameters are in good agreement with static and shock tube studies. No firm evidence could be found for any side reactions or reversibility under the experimental conditi

ISSN:0538-8066    

DOI:10.1002/kin.550100110

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550100101

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY