624-91-9Relevant academic research and scientific papers
Atmospheric chemistry of hexafluorocyclobutene, octafluorocyclopentene, and hexafluoro-1,3-butadiene
Wallington,Hurley
, p. 19 - 23 (2011)
The relative rate method was used to measure k(Cl + hexafluorocyclobutene) = (8.88 ± 0.69) × 10-13, k(Cl + octafluorocyclopentene) = (1.02 ± 0.11) × 10-12, k(Cl + hexafluoro-1,3- butadiene) = (7.28 ± 0.99) × 10-11, k(OH + hexafluorocyclobutene) = (8.6 ± 1.6) × 10-14, k(OH + octafluorocyclopentene) = (1.01 ± 0.16) × 10-13, and k(OH + hexafluoro-1,3-butadiene) = (9.64 ± 1.76) × 10-12 cm3 molecule-1 s-1 in 700 Torr N2, or air, diluent at 295 K. The atmospheric lifetimes of hexafluorocyclobutene, octafluorocyclopentene, and hexafluoro-1,3-butadiene were estimated to be 135, 104, and 1.1 days, respectively. The 100 year time horizon global warming potentials for hexafluorocyclobutene and octafluorocyclopentene are 42 and 28.
Direct Measurement of the Rate Constants in the Reaction of Nitrous Acid with Methanol
Aldred, S. Elaine,Williams, D. Lyn H.
, p. 73 - 74 (1980)
Rate constants have been determined by stopped-flow spectrophotometry and mechanisms are deduced for the nitrosation of methanol by nitrous acid (and nitrosyl chloride in water) and for the reverse reaction, the hydrolysis (or denitrosation) of methyl nitrite.
Photodissociation of Methyl Nitrate in a Molecular Beam
Yang, Xuefeng,Felder, Peter,Huber, J. Robert
, p. 10903 - 10910 (1993)
The photodissociation of methyl nitrate, CH3ONO2, has been investigated by photofragment translational spectroscopy.At the photolysis wavelength of 193 nm the predominant primary decay (ca. 70percent) involves the fission of the weak CH3O-NO2 bond (D10 ca. 41 kcal/mol) to yield CH3O + NO2 fragment pairs which show a bimodal translational energy distribution.The component consisting of the fast fragment pairs has an average translational energy (ET) = 41 kcal/mol and a recoil anistropy β = 0.9, while the slow component is characterized by (ET) = 19 kcal/mol and β = 0.A significant portion of the NO2 fragments of the slow component is subject to a unimolecular decay to NO + O(3P).An additional primary decay route leads to the formational of methyl nitrite, CH3ONO, and atomic oxygen O(1D) with (ET) = 6 kcal/mol and β = 1.2.This competing reaction requires fission of the strong N-O bond (D110 ca. 118 kcal/mol) and its occurrence indicates an initial localization of the photoexcitation on the NO2 moiety in the parent molecule.At higher laser fluence secondary photodissociation of the primary fragments CH3ONO was observed.Photolysis at 248 nm is shown to produce CH3O + NO2 fragment pairs exclusively, with (ET) = 17 kcal/mol.
Kinetic and mechanistic study of the pressure and temperature dependence of the reaction CH3O + NO
Caralp, Francoise,Rayez, Marie-Therese,Forst, Wendell,Gomez, Nathalie,Delcroix, Bruno,Fittschen, Christa,Devolder, Pascal
, p. 3321 - 3330 (1998)
New kinetic measurements for the CH3O + NO reaction have been performed using two different techniques. The discharge flow (DF) technique has been used to investigate the 0.5-5 Torr and 248-473 K pressure and temperature ranges and pulsed laser photolysis (PLP) has been used for the 30-500 Torr and 284-364 K ranges. These new results represent an extension of the pressure and temperature ranges investigated previously. This reaction is known to present two reaction pathways, the association pathway yielding CH3ONO and the disproportionation pathway yielding CH2O + HNO. Based on literature and present experimental data, using the results of ab initio calculations, a multichannel RRKM analysis was developed to interpret the experimental results. This analysis has shown that the disproportionation reaction occurs simultaneously by both a direct hydrogen abstraction reaction, and via the formation of energized CH3ONO* complex in competition with the association reaction. The RRKM analysis, fitted to present and previous data, has yielded a second-order limiting low-pressure value of 2.5 × 10-12 cm3 molecule-1 s-1 at 298 K, with a complex temperature dependence. The limiting high-pressure rate constant derived in the same way is k∞ = (3.4 ± 0.4) × 10-11(T/298)-0.75. The model allows the prediction of CH3O loss rate constants and of the branching ratios in the 1-760 Torr and 220-600 K ranges. For a convenient presentation of the overall rate constant, an analytical expression using the conventional Troe expression with a temperature-dependent addition constant, has been fitted to the results of the RRKM analysis.
Kinetics of the reactions of OH radicals with selected acetates and other esters under simulated atmospheric conditions
Williams,O'RJI,Stone
, p. 539 - 548 (1993)
The relative hydroxyl reaction rate constants from the simulated atmospheric oxidation of selected acetates and other acetates and other esters have been measured. Reactions were carried out at 297 ± 2K in 100-liter FEP teflon-film bags. the OH radicals were generated from the photolysis of methyl nitrite in pure air. Using a rate constant of 2.63 × 10-11 cm3 molecule-1 s-1 for the reaction of OH radicals with propene, principal reference organic compound, the rate constants (×1012 cm3 molecule-1 s-1) obtained for the acetates and esters used in this study. A linear correlation was observed for a plot of the measured relative rate constants vs. the number of CH2 groups per molecule of the following acetates: methyl acetate, ethyl acetate, n-propyl acetate, butyl acetate and pentyl acetate.
Low-energy Fragmentations of Five Isomeric +* Ions
Sirois, M.,Holmes, J. L.,Hop, C. E. C. A.
, p. 167 - 173 (1990)
The low-energy fragmentation characteristics of the +* isomers +* (a), +* (b), +* (c), +* (d) and +* (e) were studied in detail by metastable ion mass spectrometry.In agreement with most earlier observations, appearance energy measurements established the potential energy surface of the isomers a, b and c, showing the intricate interrelations between them.It was concluded that a isomerizes into b prior to fragmentation by loss of *OH and H2O and into c before loss of *H and H3CO* moreover, the reversereactions do not take place on the metastable time-frame.The dominant metastable process for isomers d and e (obtained via HCN loss from glyoxime) was generation of +*.For isomer e this process was proposed to involved a rate-determining isomerization into d.It was concluded that isomers d and e do not intercommunicate with ions a, b and c prior to fragmentation.Neutralization-reionization mass spectrometry indicated that the enol form of formohydroxamic acid as well as the keto conterpart are stable in the gas phase.
Collisional Quenching of CH3O(A2A1)
Wantuck, Paul J.,Oldenborg, Richard C.,Baughcum, Steven L.,Winn, Kenneth R.
, p. 3253 - 3259 (1987)
Room temperature rate constants for collisional quenching of CH3O(A2A1) have been measured for 20 collision partners.Methoxy radicals are produced by 248-nm photolysis of CH3ONO and the CH3O(A2A1) is produced by exciting the A-X transition using a pulsed dye laser.Rate constants are determined by monitoring the time-resolved fluorescence signal as a function of quenching gas pressure.The experimental quenching cross sections are best correlated in terms of the CH3O-collision partner interaction well depth.Reasonable correlation is observed for 15 quenching gases, but several exceptions are apparent.A similar trend in collision partner quenching efficiency for OH(A2Σ+) and CH3O(A2A1) is noted and discussed.
Atmospheric chemistry of cis-CF3CH=CHCl (HCFO-1233zd(Z)): Kinetics of the gas-phase reactions with Cl atoms, OH radicals, and O3
Andersen, Lene L?ffler,?sterstr?m, Freja From,Sulbaek Andersen, Mads P.,Nielsen, Ole John,Wallington, Timothy J.
, p. 289 - 293 (2015)
FTIR smog chamber techniques were used to measure the rate coefficients k(Cl + cis-CF3CH=CHCl) = (6.26 ± 0.84) × 10-11, k(OH + cis-CF3CH=CHCl) = (8.45 ± 1.52) × 10-13, and k(O3 + cis-CF3CH=CHCl) = (1.53 ± 0.12) × 10-21 cm3 molecule-1 s-1. The atmospheric lifetime of cis-CF3CH=CHCl is determined by reaction with OH radicals and is estimated to be 14 days. The infrared spectrum of cis-CF3CH=CHCl was recorded and the integrated absorption over the range 600-2000 cm-1 was measured to be (1.48 ± 0.07) × 10-16 cm molecule-1. Accounting for non-uniform horizontal and vertical mixing leads to a GWP100 value of essentially zero. Correction to account for unwanted Cl atom chemistry in our previous relative rate study of the kinetics of the reaction of OH with trans-CF3CH=CHCl gives k(OH + trans-CF3CH=CHCl) = (3.61 ± 0.37) × 10-13 cm3 molecule-1 s-1.
Atmospheric chemistry of C2F5CH2OCH 3 (HFE-365mcf)
Thomsen,Andersen,Nielsen,Wallington
, p. 2758 - 2764 (2011)
FTIR smog chamber techniques were used to measure k(Cl + C 2F5CH2OCH3) = (2.52 ± 0.37) × 10-11 and k(OH + C2F5CH 2OCH3) = (5.78 ± 1.02) × 10-13 cm3 molecule-1 s-1 in 700 Torr of air diluent at 296 ± 1 K. The atmospheric lifetime of C2F 5CH2OCH3 is estimated to be 20 days. Reaction of chlorine atoms with C2F5CH2OCH3 proceeds 18 ± 2% at the -CH2- group and 82 ± 2% at the -CH3 group. Reaction of OH radicals with C2F 5CH2OCH3 proceeds 44 ± 5% at the -CH2- group and 56 ± 5% at the -CH3 group. The atmospheric fate of C2F5CH2OCH2O radicals is reaction with O2 to give C2F 5CH2OCHO. The atmospheric fate of C2F 5CH(O)OCH3 radicals is C-C bond-cleavage to give C 2F5 radicals and CH3OCHO (methyl formate). The infrared spectrum was recorded and used to estimate a global warming potential of 6 (100 year time horizon) for C2F5CH 2OCH3.
Conformational kinetics of methyl nitrite. I. NMR spectral evidence for statistical intramolecular vibrational redistribution
Chauvel, J. Paul,Conboy, Claire B.,Chew, Wilbert M.,Matson, Gerald B.,Spring, Cheryl A.,et al.
, p. 1469 - 1476 (1984)
Pressure dependent rate constants for syn anti conformational exchange in gaseous methyl nitrite and in gaseous methyl nitrite-CO2 mixtures have been obtained from line shape analyses of 1H NMR spectra.The pressure dependence of the exchange rates is consistent with a specific reaction rate constant of ca. 1*109/s which agrees with RRKM calculations demonstrating that intramolecular vibrational redistribution is occurring at the statistical limit in methyl nitrite molecules with ca. 12 kcal/mol of internal vibrational energy.At 12 kcal/mol methyl nitrite has a state density of ca. 160/cm-1.These results indicate strong anharmonic and /or Coriolis coupling between vibrational levels.Bimolecular rate data for methyl nitrite and methyl nitrite-CO2 mixtures are consistent with a collisional efficiency βp for CO2 of 0.95(8) for activation of syn-anti conformational exchange at 258.8 K.
