2597-44-6Relevant articles and documents
Evaluation of the rate constant for the reaction OH+H2CO: Application of modeling and sensitivity analysis techniques for determination of the product branching ratio
Yetter, Richard A.,Rabitz, Herschel,Dryer, Frederick L.,Maki, Robert G.,Klemm, R. Bruce
, p. 4088 - 4097 (1989)
Novel modeling and sensitivity analysis techniques are used with experimental data obtained from discharge flow-resonance fluorescence experiments to evaluate the product branching ratio of OH + H2CO.Two channels are considered: the H-atom abstraction reaction (R2) to form HCO and H2O; and the addition reaction ( R 17 ) followed by rearrangement and decomposition to form HCOOH and H.The rate constant values obtained at 298 K are kR2 = (7.75+/-1.24) X 10-12 cm3/molecule s and kR17= (0.2-0.2+0.8) X 10-12 cm3/molecule s.The results demonstrate that the reaction proceeds almost exclusively via the H-atom abstraction pathway.
Reaction dynamics of electronically state-specific CH2 with NO
Su, Hongmei,Kong, Fanao,Chen, Bozhen,Huang, Ming-Bao,Liu, Yajun
, p. 1885 - 1890 (2000)
Density functional theory (DFT) B3LYP calculations were carried out to explore the mechanisms related to the previously observed 3CH2+NO and 1CH2+NO reaction channels. The potential energy surfaces of the observed reaction channels were described. As a result, the main reaction mechanisms of both 3CH2+NO and 1CH2+NO were clarified.
KINETICS OF POLYATOMIC FREE RADICALS PRODUCED BY LASER PHOTOLYSIS. 3. REACTION OF VINYL RADICALS WITH MOLECULAR OXYGEN.
Slagle,Park,Heaven,Gutman
, p. 4356 - 4361 (1984)
The kinetics and mechanism of the gaseous reaction of vinyl radicals with molecular oxygen have been studied between 297 and 602 K. The radicals were produced in a heated tubular reactor by the pulsed laser photolysis of C//2H//3Br at 193 nm. Reactant and product concentrations were monitored in real-time experiments using photoionization mass spectrometry. The products formed in this temperature range are HCO and H//2CO. The overall rate constant is pressure independent and is nearly constant with temperature: k equals 6. 6 ( plus or minus 1. 3) multiplied by 10** minus **1**2 exp(250 plus or minus 100 cal/RT) cm**3 molecule** minus **1 s** minus **1. The magnitude of the rate constant, its temperature and pressure dependence, and the identity of the products of this reaction indicate that it proceeds by an addition mechanism in which the adduct rapidly rearranges to form an energy-rich dioxetanyl intermediate which decomposes into the observed products. Two other reactions (C//2H//3 plus i-C//4H//1//0 and C//3H//5 (allyl radical) plus O//2) were investigated at elevated temperatures, but no reaction was detected.
Branching Ratios in O(3P) Reactions of Terminal Olefins Studied by Kinetic Microwave Absorption Spectroscopy
Koda, Seiichiro,Endo, Yasuki,Tsuchiya, Soji,Hirota, Eizi
, p. 1241 - 1244 (1991)
O(3P) atom reactions with ethylene, propylene, and 1-butene were studied by use of kinetic microwave absorption spectroscopy where the atomic oxygen was supplied via ArF excimer laser photolysis of SO2.Time evolutions of vinoxy, HCO, and H2CO were pursued.The fraction of vinoxy production in the propylene and 1-butene reactions at 30 mTorr was found to be 0.29 +/- 0.15 and 0.37 +/- 0.15, respectively.The fractions seemed to increase with decrease in pressure, by comparing the present results with those of several previous researchers.Therefore, at least some part of the vinoxy production fraction is pressure dependent.The reaction scheme explaining the pressure-dependent part is suggested as follows.Initially, a triplet biradical is produced through O(3P) attack to the terminal carbon atom of the C=C double bond, which is then converted to a singlet biradical.Subsequently, a hydrogen atom migrates and then the C-C bond adjacent to the original C=C double bond dissociates to yield the vinoxy and corresponding alkyl radicals.Thus, some part of the vinoxy radical is produced via a quite different mechanism from the case of ethylene reaction, where it is produced via a direct substitution channel on a triplet surface.
ESR study of low-temperature radiolysis and photolysis of substituted N′-furfurylidenebenzhydrazides
Gordon,Chuev,Aldoshin,Mikhailov
, p. 2055 - 2059 (1999)
Low-temperature (77 K) γ- and UV irradiation of substituted N′-furfurylidenebenzhydrazides produces paramagnetic particles in radiation-chemical yields of (0.05-0.5)/100 eV and quantum yields of 4 · 10-5-10-3, respectively. ESR study showed that hydrazyl radicals and HC- O and N -O2 are the main products of radiolysis and photolysis, and the latter decay upon heating of the sample to 190 K, whereas the hydrazyl radicals survive up to 423 K. Further heating results in thermodestruction of the hydrazides, and the ESR spectrum exhibits only a singlet with splitting at 1 mT, which is characteristic of polyconjugated compounds.
Electron bombardment matrix isolation of Rg/Rg′/methanol mixtures (Rg= Ar, Kr, Xe): Fourier-transform infrared characterization of the proton-bound dimers Kr2H+, Xe2H+, (ArHKr)+ and (ArHXe)+ in Ar matrices and (KrHXe)+ and Xe2H+ in Kr matrices
Fridgen, Travis D.,Parnis, J. Mark
, p. 2155 - 2161 (1998)
Matrices formed by subjecting methanol vapor diluted in argon/krypton mixtures to electron bombardment and subsequent matrix isolation (EBMI) reveal a new feature at 885.3 cm-1 which is assigned to the v3 fundamental of the triatomic cation (ArHKr)+. In samples containing about 5% krypton, the v3 fundamental of Kr2H+ is also observed in a predominantly solid argon environment. These assignments are supported by annealing experiments and by density functional theory calculations reported in a separate paper. Similar experiments with xenon diluted in argon yield infrared spectra showing the v3 and v3+v1 bands of (ArHXe)+, and v3 of Xe2H+ in predominantly argon environments. EBMI of methanol diluted in krypton in the presence of xenon gives rise to infrared bands assigned to the v3 and v3+v1 fundamentals and combination bands of both (KrHXe)+ and Xe2H+ isolated in predominantly krypton environments. The energetics and plausible mechanisms to the formation of these homogenous and mixed proton-bound rare-gas dimers are considered.
Kinetic Study of the NO3-CH2O Reaction and Its Possible Role in Nighttime Tropospheric Chemistry
Cantrell, Christopher A.,Stockwell William R.,Anderson, Larry G.,Busarow, Kerry L.,Perner, Dieter,et al.
, p. 139 - 146 (1985)
The kinetics of the reaction NO3 + CH2O -> HONO2 + HCO (14) have been studied by using in situ, long-path (170 m), infrared and visible spectroscopy to follow the reactants and products in dilute mixtures of O3, NO2, and CH2O in N2/O2 at 700 torr (25 +/- 2 deg C).The concentrations of O3, NO2, CH2O, N2O5, CO, HONO2, and HCO2H were detrmined as a function of time through their characteristic infrared absorption bands by using a Fourier transform infrared spectrometer system.The concentrations of NO3 and NO2 were followed by using the characteristic visible absorption bands monitored by a differential optical absorption spectrometer.The kinetic data were analyzed by using both rates of product formation (CO) and reactant removal (N2O5, NO3, CH2O) and computer simulations of the complex reactions which follow reaction 14 in these systems.The reults show that the use alone of N2O5 decay rates in the presence and absence of CH2O to derive k14 estimates can lead to significant error as a result of the generation of secondary radicals (HO2, HO) following the primary reaction 14 and the subsequent reactions of HO with CH2O and HO2 with NO3.The present data provide the estimate k14 = (6.3 +/- 1.1)*10-16 cm3 molecule-1 s-1 (25 +/- 2 deg C).
Crossed molecular beam study of the reaction O(3P) + allene
Schmoltner, A. M.,Huang, S. Y.,Brudzynski, R. J.,Chu, P. M.,Lee, Y. T.
, p. 1644 - 1653 (1993)
The reaction between ground state (3P) oxygen atoms and allene was studied under single collision conditions using the crossed molecular beams method.Product angular distributions and the translational energy distribution were determined for ea
Kinetics of the reactions of vinyl radicals with molecular oxygen and chlorine at temperatures 200-362 K
Eskola,Timonen
, p. 2557 - 2561 (2003)
The kinetics of the C2H3 + O2 and C2H3 + Cl2 reactions have been studied in direct measurements at temperatures between 200-362 K using a tubular flow reactor coupled to a photoionization mass spectrometer (PIMS). The vinyl radicals were homogeneously generated by the pulsed laser photolysis of methyl vinyl ketone at 193 nm. The subsequent decays of the radical concentrations were monitored in time-resolved measurements to obtain the reaction rate coefficients under pseudo-first-order conditions. Reaction products identified were HCO and H2CO for the oxygen reaction and C2H3Cl for the chlorine reaction, respectively. The rate coefficients of both reactions were independent of the bath gases (He or N2) and pressures within the experimental range, 0.13-0.53 kPa, and can be expressed by the Arrhenius equations k(C2H3 + O2) = (4.62 ± 0.40) × 10-12 exp(1.41 ± 0.18 kJ mol-1/RT) cm3 molecule-1 s-1 and k(C2H3 + Cl2) = (4.64 ± 0.59) × 10-12 exp(3.12 ± 0.27 kJ mol-1/RT) cm3 molecule-1 s-1, where uncertainties are one standard deviation. These experimental results obtained by using our new apparatus are in good agreement with previous direct measurements.
Ultraviolet photodissociation of furan probed by tunable synchrotron radiation
Sorkhabi, Osman,Qi, Fei,Rizvi, Abbas H.,Suits, Arthur G.
, p. 100 - 107 (1999)
The ultraviolet photodissociation dynamics of furan were studied using photofragment translational spectroscopy. Three product channels were observed: the radical channel, the CO+C3H4 channel, and the C2H2+ketene channel. All channels exhibited a dissociation barrier, with the C2H2+ketene channel having the largest value. The CO+C3H4 and C2H2+ketene channels occurred on the ground-state potential energy surface.
