摘要:

AbstractThe gas‐phase reaction of isoprene with the OH radical, in the resence of NOx, was investigated at 298 ± 2 K and atmospheric pressure of air by long path length FT‐IR spectroscopy. The primary products identified and their formation yields were: methacrolein, 0.21 ± 0.05; methyl vinyl ketone, 0.29 ± 0.07; and HCHO, with the observed yield being consistent with the sum of the methacrolein and methyl vinyl ketone yields. Combined with the previously reported yield of 0.044 ± 0.006 for 3‐methylfuran, these products accounted for 55 ± 9% of the isoprene which reacted. Under conditions where the dark reaction of isoprene with NO2is not significant, the balance of the isoprene consumed could possibly be accounted for by the “organic nitrates” and “other carbonyl compounds” formed in estimated overall yields of ca. 12% and ca.

ISSN:0538-8066    

DOI:10.1002/kin.550221202

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe kinetics of base hydrolysis ofthecis‐(chloro)‐(benzimidazole)bis(ethylenediamine) cobalt(III) ion was investigated in Methanol‐water and Ethyleneglycol‐water media of varying compositions and at isodielectric conditions(Ds≃ 61 at 25°C) in isopropanol‐ and Acetonitrile‐water media at 35°C in the pH range, 7.2–8.9. It is of interesttonote that the aquation rate constant of the conjugate base,cis‐[Co(en)2(bzm)Cl]+(Bzm = N H deprotonated benzimidazole, en = ethylenediamine) is virtually insensitive to the compositions of the mixed solvents studied, unlike the aquation rate constant of the conjugate acid form of the title complex. This is indicative of a true dissociative mode of activation (Dcb)

ISSN:0538-8066    

DOI:10.1002/kin.550221203

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractElimination kinetics of 2‐bromohexane and 2‐bromo‐4‐methylpentane in the gas phase were examined over the temperature range of 310–360°C and pressure range of 46–213 torr. The reactionsin seasoned, static reaction vessels, and in the presence of the free radical inhibitor cyclohexene, are homogeneous, unimolecular, and follow first order rate laws. The overall rate coefficients are described by the following Arrhenius equations: For 2‐bromohexane, log

ISSN:0538-8066    

DOI:10.1002/kin.550221204

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe mechanisms for the Cl‐initiated and OH‐initiated atmospheric oxidation oft‐butyl alcohol (TBA), methylt‐butyl ether (MTBE), and dimethyl ether (DME) have been determined. For TBA the only products observed are equimolar amounts of H2CO and acetone, and its atmospheric oxidation can be represented by (7),The mechanism for the atmospheric oxidation of DME is also straight forward, with the only observable product being methyl formate,The mechanism for the atmospheric oxidation of MTBE is more complex, with observable products beingt‐butyl formate (TBF) and H2CO. Evidence is presented also for the formation of 2‐methoxy‐2‐methyl propanal (MMP), which is highly reactive and presumably oxidized to products. The atmospheric oxidation of MTBE can be represented by (9) and (10),In terms of atmospheric reactivity, DME, TBA, and MTBE all compare favorably with methanol. In terms of rate of reaction in the atmosphere, DME, MTBE, and TBA are 1.4, 0.40, and 0.28 times as reactive as CH3OH towards OH on a per carbon basis. With regard tochemistry, atmospheric oxidation of CH3OH yields highly reactive H2CO as the sole carbon‐containing product. In contrast, only 25% of the carbon in TBA is converted to H2CO, with the balance yielding unreactive acetone. For DME, all the carbon is converted to methyl formate which is unreactive. Finally, for MTBE, 60% is converted to unreactive TBF while the remaining 40% produces highly reactive MMP.Final assessment of the impact of these materials on the atmospheric reactivity of vehicle emissions requires the determination of their emissions rates under realistic ope

ISSN:0538-8066    

DOI:10.1002/kin.550221205

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThis article reports the kinetics of the decomposition of N‐bromoserine formed rapidly by bromation of serine by BrO−. The main decomposition products are glycolaldehyde, ammonia, carbon dioxide, and bromide ions at pH11 and with decreasing pH at pH<8, and over the range pH 8–11 has the constant value 1.67 × 10

ISSN:0538-8066    

DOI:10.1002/kin.550221206

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe kinetics of the deactivation of O2(1Σg+) is studied in real time. O2(1Σg+) is generated in this system by the O(1D) + O2reaction following O3laser flash photolysis in the presence of excess O2, and it is monitored by its characteristic emission band at 762 nm. Quenching rate constants were obtained for O2, O3, N2, CO2, H2O, CF4and the rare gases. Since O(1D) is the precursor for the formation of O2(1Σg+), the addition of an O(1D) quencher effectively lowers the initial concentration of O2(1Σg+). By measuring the initial intensity of the 762 nm fluorescence signal, the relative quenching efficiencies were determined for O(1D) quenching by N2, CO2, Xe, and Kr with respect to O2; the results are in good agreement with literature val

ISSN:0538-8066    

DOI:10.1002/kin.550221207

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550221208

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550221201

出版商:John Wiley&Sons, Inc.    

年代:1990

数据来源: WILEY