摘要:

AbstractHCO radical at a concentration of about 1014cm−3is produced by monochromatic laser photolysis of H2CO with a 0.6 mJ frequency‐doubled, flashlamp‐pumped dye laser pulse. Intracavity dye laser spectroscopy quantitatively monitors HCO absorbance near 614 nm as a function of delay time between photolysis and probing pulses. Rate constants for HCO + O2and HCO + NO are found to be 4.0 ± 0.8 × 10−12and 1.45 ± 0.2 × 10−11cm3mo

ISSN:0538-8066    

DOI:10.1002/kin.550100502

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe autoinhibiting reaction of ozone with dimethyl sulfide (DMS), has been studied at 296°K and 1.1 kPa (8 torr) as a function of the concentrations of both reactants. The major products of the reaction are H2CO, H2O, CO, and SO2. The specific rate of primary attack of O3on DMS is immeasurably slow. It is suggested that the rapid overall rate observed for this reaction is due to a chain reaction initiated by the very slow primary reaction. It is concluded that reaction (1) cannot be important under atmospheric conditions and that the major loss process for DMS in the atmosphere is probably reaction with photochemically generated free radicals

ISSN:0538-8066    

DOI:10.1002/kin.550100503

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe kinetics of the thermal decomposition oftrans‐1,2‐dicyanocyclobutane, which yields only vinyl cyanide, have been studied in the temperature range of 570°‐660°K using a stirred‐flow reactor. The reaction was found to be first order and homogeneous with rate constants represented by the Arrhenius equation\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log}k{\rm (sec}^{- 1} {\rm) =}{{{\rm (16}{\rm .0} \pm {\rm 0}{\rm .3)} - {\rm (52}{\rm .9} \pm {\rm 0}{\rm .8)}} \mathord{\left/ {\vphantom {{{\rm (16}{\rm .0} \pm {\rm 0}{\rm .3)} - {\rm (52}{\rm .9} \pm {\rm 0}{\rm .8)}} \theta}} \right. \kern-\nulldelimiterspace} \theta} $$\end{document}where θ = 2.303RTkcal/mol. The Arrhenius parameters are considerably higher than previously reported. On the assumption of a biradical mechanism the results are consistent with a cyano stabilization energy of ∼5 kcal/mol, in good agreement with the results of recent studies of rel

ISSN:0538-8066    

DOI:10.1002/kin.550100504

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractA program system is described for the integration of the rate equations resulting from large systems of elementary reactions. The Gear integration method is used for this problem, which frequently may exhibit stiffness instability when other integration methds are employed. No usage of the quasi‐steady‐state approximation is necessary. Ease in varying the reaction mechanism and simplicity of input structure are coupled with efficient execution and minimal demands for program storage as key features. The input–output structure, method of operation, and implementation are summarized, along with core storage requirements and execution times for trials using an IBM 360/44 com

ISSN:0538-8066    

DOI:10.1002/kin.550100505

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractA temperature dependence study of the ultrasonic amplitudes, velocities, and relaxation times for a presumed conformational transition of noncomplexed aqueous 18‐crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane) is discussed. At all temperatures a single relaxation was observed within a 15–255‐MHz frequency range. The equilibrium constant for the presumed conformational transition\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CR}_1 \mathop \rightleftarrows\limits^{K_{12} } {\rm CR}_2 $\end{document}was determined to beK21= (2 ± 2) × 10−2. The activation parameters are ΔH21≠= 10.2 ± 1.0 kcal/mol, ΔS21≠= 7.7 ± 0.2 cal/(mol·deg), ΔH12≠= 7.4 ± 1.0 kcal/mol, and ΔS12≠= 7.7 ± 0.2 cal/(mol·deg), while the thermodynamic enthalpy and entropy were found to be −2.6 ± 1.0 kcal/mol and 0 ± 0.2 cal/(mol·deg), respectively. The rate constants at 25.0°C for the presumed conformational transition arek21= (1.0 ± 0.3) ×

ISSN:0538-8066    

DOI:10.1002/kin.550100506

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractRate constants as a function of both temperature and pressure were calculated for the title reactions using RRKM theory in conjunction with a modified Gorin transition state. The modification introduces a hindrance parameter which accounts for repulsive interactions between the rotating fragments. At the highest stratospheric pressures (∼50 torr) and at stratospheric temperature (∼220°K), the extent of “falloff” from first‐order [N2] dependence is ∼70% for reaction (1) and ∼35% fo

ISSN:0538-8066    

DOI:10.1002/kin.550100507

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe recombination of carbon monoxide and oxygen atoms was studied in reflected shock waves in H2:O2:CO:Ar = 0.1:1:24:75 with 1300

ISSN:0538-8066    

DOI:10.1002/kin.550100508

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe rate constantk4has been measured at 268°, 298°, and 334° K for the reaction CH2O + 2OH → CO + 2H2O relative to that for OH + OH (k2) by competition experiments in a discharge flow tube using mass‐spectrometric analysis. Based onk2= 2.24 × 10−12cm3/molec·sec at 298°K andE2= 4 kJ/mol,k4= (6.5 ± 1.5) × 10−12cm3/molec·sec at 298°K and

ISSN:0538-8066    

DOI:10.1002/kin.550100509

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550100501

出版商:John Wiley&Sons, Inc.    

年代:1978

数据来源: WILEY