The Hydroxymethyl (•CH2OH) radical is an important intermediate species in both atmosphere and combustion reaction systems. The rate coefficients for •CH2OH + 3O2 and (CH2OH + 3O2 (+H2O) reactions were...

The rate coefficient for the gas-phase reaction of Cl atoms with ethyl formate was measured over the temperature range of 268-343 K using relative rate methods, with ethyl chloride as a reference compound. The temperature dependent relative rate coefficients for the ethyl formate + Cl reaction were measured, and the modified Arrhenius expression kethyl formate(268-343) = (2.54 ± 0.57) × 10(-23) T(4.1) exp {-(981 ± 102)/T} cm(3) molecule(-1) s(-1) was obtained with 2σ error limits. The room temperature rate coefficient for the title reaction is (9.84 ± 0.79) × 10(-12) cm(3) molecule(-1) s(-1), which is in good agreement with reported values. To complement the experimental measurement, computational methods were used to calculate the rate coefficient for the ethyl formate + Cl reaction atoms using canonical variational transition state theory (CVT) with small curvature tunneling (SCT) and the CCSD (T)/cc-pVDZ//M062X/6-31+g(d,p) level of theory. The temperature dependent Arrhenius expression was obtained to be 2.97 × 10(-18) T(2.4) exp[-(390/T)] cm(3) molecule(-1) s(-1) over the temperature range of 200-400 K. The thermodynamic parameters and branching ratio were calculated. Also, the atmospheric lifetime and global warming potentials (GWPs) were calculated for ethyl formate.

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We recorded time-resolved infrared absorption spectra of transient species produced on irradiation at 308 nm of a flowing mixture of CHI/O/N/SO at 298 K. Bands of CHOO were observed initially upon irradiation; their decrease in intensity was accompanied by the appearance of an intense band at 1391.5 cm that is associated with the degenerate SO-stretching mode of SO, two major bands of HCHO at 1502 and 1745 cm, and five new bands near >1340, 1225, 1100, 940, and 880 cm. The band near 1340 cm was interfered by absorption of SO and SO, so its band maximum might be greater than 1340 cm. SO in its internally excited states was produced initially and became thermalized at a later period. The rotational contour of the band of thermalized SO agrees satisfactorily with the reported spectrum of SO. These five new bands are tentatively assigned to an intermediate 1,3,2-dioxathietane-2,2-dioxide [cyc-(CH)O(SO)O] according to comparison with anharmonic vibrational wavenumbers and relative IR intensities predicted for this intermediate. Observation of a small amount of cyc-(CH)O(SO)O is consistent with the expected reaction according to the potential energy scheme predicted previously. SO+HCHO are the major products of the title reaction. The other predicted product channel HCOOH+SO was unobserved and its branching ratio was estimated to be <5%.