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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 8 (1989), S. 87-94 
    ISSN: 1573-0662
    Keywords: Atmospheric photo-oxidation ; hydroxyl-radicals ; diethylether ; di-n-propylether ; di-n-butylether ; di-isobutylether ; ethyl n-butylether ; ethyl t-butylether ; smog chamber ; kinetic studies ; relative rate coefficients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Rate coefficients have been measured for the reactions of hydroxyl radicals with a range of aliphatic ethers by a competitive technique. Mixtures of synthetic air containing a few ppm of nitrous acid, isobutene and an ether were photolyzed in a Teflon-bag smog chamber. From the rates of depletion of the ether and of the isobutene, and based on the value of the rate coefficient k(OH+i-C4H8)=5.26×10-11 cm3 molecule-1 s-1, the following rate coefficients were obtained for the hydroxyl radical reactions at 750 Torr and at 294±2K in units of 10-12 cm3 molecule-1 s-1: diethylether = 12.0±1.1, di-n-propylether = 15.3±1.6, di-n-butylether=17.1±0.9, ethyl n-butylether = 13.5±0.4, ethyl t-butyl-ether = 5.6±0.5, and di-isobutylether = 26.1±1.6. The quoted error limits correspond to 2 standard deviations but do not include any contribution from k(OH+i-C4H8) for which the error limits are estimated to be about ±10%. The results are discussed in relation to the available literature data and considered in terms of the structure-activity relation for hydroxyl radical reactions with organic molecules.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-0662
    Keywords: Atmospheric photo-oxidation ; acetone ; ethanol ; isopropyl acetate ; n-propyl acetate ; methyl nitrate ; ethyl nitrate ; n-propyl nitrate ; hydroxyl radical ; smog chamber ; kinetic studies ; relative rate constants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Rate constants have been measured for the reactions of hydroxyl radicals with alkyl nitrates and with some oxygen-containing organic compounds by a competitive technique. Mixtures of synthetic air containing a few ppm of nitrous acid, ethylene and the organic substrate were photolysed in a Teflon bag smog chamber. Based on the value k HO+C2H4}=8.1×10-12 cm3 molecule-1 s-1 the following rate constants were obtained for the hydroxyl radical reactions at 750 Torr and at 303 K in units of 10-12 cm3 molecule-1: CH3ONO2, 0.37±0.09; C2H5ONO2, 0.48±0.20; n-C3H7ONO2, 0.70±0.22; C2H5OH, 3.6±0.4; CH3COCH3, 0.26±0.08; CH3CO2 i-C3H7, 3.0±0.8; CH3CO2 n-C3H7, 2.4±0.2. The results are discussed in relation to the available literature data and the implications of the results are considered in terms of the ‘smog reactivity’ of these molecules.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-0662
    Keywords: Atmospheric photo-oxidation ; alkoxy radicals ; isopropyl acetate ; n-propyl acetate ; nitrous acid ; hydroxyl radical ; smog chamber ; reaction mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The formation of products following the hydroxyl radical initiated photo-oxidations of n-and isopropyl acetates has been studied. Mixtures of synthetic air containing a few ppm of nitrous acid, nitric oxide, nitrogen dioxide and one of the propyl acetates were irradiated with sunlamps in a Teflon bag smog chamber. The decay of reactants and the formation of products was monitored by chemiluminescent analysis or by gas chromatography. The major primary products from the photo-oxidation of n-propyl acetate are acetaldehyde and propionaldehyde while from isopropyl acetate they are acetone and methyl nitrate. It was not possible to analyse for formaldehyde, an expected primary product in these systems. The nature and distribution of products indicate that a significant fraction of primary products arise from decomposition reactions of the alkoxy-type radicals generated following the initial attack of hydroxyl radicals on the esters. The derived reaction stoichiometries (molecules of NO oxidised per molecule of ester reacted) are also consistent with the proposed mechanisms.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-0662
    Keywords: Atmospheric photo-oxidation ; hydroxyl radicals ; diethyl ether ; methyln-butyl ether ; ethyln-butyl ether ; di-n-butyl ether ; di-n-pentyl ether ; relative rate coefficients ; smog chamber kinetic studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The following temperature-dependent rate coefficients (k/cm3 molecule−1 s−1) of the reactions of hydroxyl radicals with aliphatic ethers have been determined over the temperature range 247–373 K by a competitive flow technique: diethyl ether,k OH=5.2×10−12 exp[(262±150)/T]; methyln-butyl ether,k OH=5.4×10−12 exp[(309±150)/T]; ethyln-butyl ether,k OH=7.3×10−12 exp[(335±150)/T]; di-n-butyl ether,k OH=5.5×10−12 exp[(502±150)/T] and di-n-pentyl ether,k OH=8.5×10−12 exp[(417±150)/T]. The data have been measured relative to the rate coefficientk(OH + 2,3-dimethylbutane)=6.2×10−12 cm3 molecule−1 s−1 independent of temperature. Previous discrepancies in the room-temperature rate coefficients for the OH reactions with ethyln-butyl ether and di-n-butyl ether, obtained in the flow and static experiments of Bennett and Kerr (J. Atmos. Chem. 8, 87–94, 1989;10, 29–38, 1990) compared with those of Wallingtonet al. (Int. J. Chem. Kinet. 20, 541–547, 1988;21, 993–1001, 1989) and of Nelsonet al. (Int. J. Chem. Kinet. 22, 1111–1126, 1990) have been resolved. The results are considered in relation to the available literature data and evaluated rate expressions are deduced where possible. The data are also discussed in terms of structure-activity relationships.
    Type of Medium: Electronic Resource
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