3958-66-5Relevant articles and documents
Rate Constants of the Reactions of CF3O2, i-C3H7O2 and t-C4H9O2 with NO
Peeters, J.,Vertommen, J.,Langhans, I.
, p. 431 - 436 (2007/10/02)
The kinetics of the title reactions have been studied at T = 290 K and p = 2 Torr He using the fast-flow technique combined with molecular-beam sampling mass spectrometry. - In our novel approach, the total rate constant k1 of RO2 + NO -> RO + NO2/RONO2 is determined from the shape of the NO2-growth profile.The validity of the method is demonstrated by the nearly identical results for k1(CF3O2 + NO) obtained from CF3O2-decays: k1 = (1.54 +/- 0.35)*10-11 and from NO2-growths: k1 = (1.51 +/- 0.4)*10-11 cm3 s-1, in excellent agreement also with previous determinations. - Rate coefficient data of alkylperoxy + NO reactions, derived from NO2-profiles, are reported for i-C3H7O2 + NO: k1 = (5.0 +/- 1.2)*10-12 and for t-C4H9O2 + NO: k1 = (4.0 +/- 1.1)*10-12 cm3 s-1.Our results, in combination with literature values for smaller peroxy radicals, indicate a marked decrease of the rate coefficient with increasing CH3-substitution.Including data on haloalkyl- and acetylperoxy reactions, the reactivity of RO2 towards NO is shown to correlate with the electron acceptor/donor properties of substituents on the α-carbon.Atmospheric Chemistry / Chemical Kinetics / Elementary Reactions / Mass Spectrometry / Radicals
Photodissociation of Alkyl Nitrites in a Molecular Beam. Primary and Secondary Reactions
Effenhauser, C. S.,Felder, P.,Huber, J. Robert
, p. 296 - 302 (2007/10/02)
The translational energy distributions P(ET) for the 248-nm photodissociation products (NO + RO) of isopropyl nitrite and tert-butyl nitrite have been measured with a molecular beam time-of-flight (TOF) apparatus.Previous experiments with methyl nitrite and ethyl nitrite have been repeated with higher resolution.The average photofragment translation energies of these four alkyl nitrites are in good agreement with those predicted by an impulsive model that treats the NO as a rigid fragment and the alkoxy radical as a soft fragment.Hence, and in contrast to the vibrational predissociation on the S1 potential energy surface, S2 dissociation is direct and involves no significant "vibrational-translational" coupling between the reaction coordinate rO-N and the rN=O coordinate.The width of the experimental P(ET) distributions decreases with increasing size of the alkoxy substituent.This result is discussed in terms of an anticorrelation between the internal energies of a fragment pair.Furthermore, the spontaneous secondary dissociation of isopropoxy and tert-butoxy photofragments was observed which yields CH3 radicals and acetaldehyde or acetone, respectively.The unimolecular decay of these alkoxy radicals confirms their relatively high internal energy as deduced from the primary P(ET) and it is shown that this decay occurs on a submicrosecond time scale.
