Gas phase UV and IR absorption spectra of CxF2x+1CHO (x = 1–4)

Hashikawa, Yoshifumi; Kawasaki, Masahiro; Waterland, Robert L.; Hurley, M. D.; Ball, James C.; Wallington, Timothy J.; Andersen, Mads Peter; Nielsen, Ole John

doi:10.1016/j.jfluchem.2004.07.006

Cited by 19 publications

(23 citation statements)

References 45 publications

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“…Uncertainties of 5% in the measured concentrations of the aldehydes were added to the reported errors in the cross sections. The maximum values determined in this work for the absorption cross sections of C 3 F 7 CHO and C 4 F 9 CHO are (8.1 AE 0.6) Â 10 À20 and (9.4 AE 0.7) Â 10 À20 cm 2 molecule À1 , respectively, are in good agreement with those previously reported by Hashikawa et al 15 and by Chiappero et al, 6 which are also shown in Fig. 3.…”

Section: Uv-absorption Cross Sectionssupporting

confidence: 92%

The gas phase tropospheric removal of fluoroaldehydes (CxF2x+1CHO, x = 3, 4, 6)

Solignac

Mellouki

Bras

et al. 2007

Phys. Chem. Chem. Phys.

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The rate coefficient of the OH reaction with the perfluoroaldehydes C 3 F 7 CHO and C 4 F 9 CHO have been determined in the temperature range 252-373 K using the pulsed laser photolysis-laser induced fluorescence (PLP-LIF) method: k C 3 F 7 CHO+OH = (2.0 AE 0. , respectively, at 298 K. The UV absorption cross sections of these two aldehydes and CF 3 (CF 2 ) 5 CH 2 CHO have been measured over the range 230-390 nm at 298 K and also at 328 K for CF 3 (CF 2 ) 5 CH 2 CHO. The obtained results for C 3 F 7 CHO and C 4 F 9 CHO are in good agreement with two recent determinations but the maximum value of the absorption cross section for CF 3 (CF 2 ) 5 CH 2 CHO is over a factor of two lower than the single one recently published. The photolysis rates of C 3 F 7 CHO, C 4 F 9 CHO and CF 3 (CF 2 ) 5 CHO have been measured under sunlight conditions in the EUPHORE simulation chamber in Valencia (Spain) at the beginning of June. The photolysis rates were, respectively, J obs = (1.3 AE 0.6) Â 10 À5 , (1.9 AE 0.8) Â 10 À5 and (0.6 AE 0.3) Â 10 À5 s À1. From the J obs measurements and calculated photolysis rate J calc , assuming a quantum yield of unity across the atmospheric range of absorption of the aldehydes, quantum yields J obs /J calc = (0.023 AE 0.012), (0.029 AE 0.015) and (0.046 AE 0.028) were derived for the photodissociation of C 3 F 7 CHO, C 4 F 9 CHO and CF 3 (CF 2 ) 5 CHO, respectively. The atmospheric implication of the data obtained in this work is discussed. The main conclusion is that the major atmospheric removal pathway for fluoroaldehydes will be photolysis, which under low NO x conditions, may be a source of fluorinated carboxylic acids in the troposphere.

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Section: Uv-absorption Cross Sectionssupporting

confidence: 92%

The gas phase tropospheric removal of fluoroaldehydes (CxF2x+1CHO, x = 3, 4, 6)

Solignac

Mellouki

Bras

et al. 2007

Phys. Chem. Chem. Phys.

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“…Scott and Radom [20] reported that the B3LYP/6-31G* method yields a rootmean-square error of 34 cm À1 for a set of 122 molecules and 1066 experimental vibrational frequencies. Hashikawa et al, [21] for example, used the same computational method for predicting the IR spectra of fluorinated aldehydes, C x F 2x + 1 CHO (x = 1-4), which reproduces with good accuracy the observed fundamental vibrational frequencies.…”

Section: Methodsmentioning

confidence: 99%

Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

et al. 2010

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A comprehensive study of several atmospheric degradation routes for two hydrofluoroalcohols, CF(3)(CH(2))(x=1,2)CH(2)OH, is presented. The gas-phase kinetics of their reactions with hydroxyl radicals (OH) and chlorine (Cl) atoms are investigated by absolute and relative techniques, respectively. The room-temperature rate coefficients (±σ, in cm(3) molecule(-1) s(-1)) k(OH) and k(Cl), are respectively (9.7±1.1)×10(-13) and (1.60±0.45)×10(-11) for CF(3)CH(2)CH(2)OH, and (2.62±0.32)×10(-12) and (8.71±0.24)×10(-11) for CF(3)(CH(2))(2)CH(2)OH. Average lifetimes of CF(3)CH(2)CH(2)OH and CF(3)(CH(2))(2)CH(2)OH due to the OH and Cl reactions are estimated to be 12 and 4 days, and greater than 20 and 4 years, respectively. Also, the IR and UV absorption cross sections of CF(3)(CH(2))(x=1,2)CH(2)OH are determined in the spectral ranges of 500-4000 cm(-1) and 200-310 nm. Photolysis of CF(3)(CH(2))(x=1,2)CH(2)OH in the actinic region (λ≥290 nm) is negligible compared to their homogeneous removal. Additionally, computational IR spectra are consistent with the experimental ones, thus giving high confidence in the obtained results. The lifetimes of CF(3)(CH(2))(x=1,2)CH(2)OH and IR spectra reported herein allow the calculation of the direct global warming potential of these hydrofluoroalcohols. The contribution of CF(3)(CH(2))(x)CH(2)OH to radiative forcing of climate change will be negligible.

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“…A slight bathochromic effect (l max around 300 nm) is observed in the CF 3 CHO np* transition band. 9,10,14 In this work, a 9% decrease in s l max (CF 3 CH 2 CHO) was observed between 269 and 298 K. Chiappero et al 10 also reported a negligible effect of temperature on s l (CF 3 CH 2 CHO) (within the experimental uncertainty) between 269 and 298 K. A comparison between the UV absorption spectra of CF 3 CH 2 CHO obtained in this work at 298 K with those reported by Selleva˚g et al 9 and Chiappero et al 10 is presented in Fig. 1b.…”

Section: Uv Absorption Cross Sections (R K ) As a Function Of Tempera...mentioning

confidence: 99%

UV absorption cross sections between 230 and 350 nm and pressure dependence of the photolysis quantum yield at 308 nm of CF3CH2CHO

Antiñolo

Jiménez

Albaladejo

2011

Phys. Chem. Chem. Phys.

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Ultraviolet (UV) absorption cross sections of CF(3)CH(2)CHO were determined between 230 and 350 nm by gas-phase UV spectroscopy. The forbidden n → π* transition was characterized as a function of temperature (269-323 K). In addition, the photochemical degradation of CF(3)CH(2)CHO was investigated at 308 nm. The possible photolysis channels are: CF(3)CH(2) + HCO , CF(3)CH(3) + CO , and CF(3)CH(2)CO + H . Photolysis quantum yields of CF(3)CH(2)CHO at 308 nm, Φ(λ=308nm), were measured as a function of pressure (25-760 Torr of synthetic air). The pressure dependence of Φ(λ=308nm) can be expressed as the following Stern-Volmer equation: 1/Φ(λ=308nm) = (4.65 ± 0.56) + (1.51 ± 0.04) × 10(-18) [M] ([M] in molecule cm(-3)). Using the absorption cross sections and the photolysis quantum yields reported here, the photolysis rate coefficient of this fluorinated aldehyde throughout the troposphere was estimated. This calculation shows that tropospheric photolysis of CF(3)CH(2)CHO is competitive with the removal initiated by OH radicals at low altitudes, but it can be the major degradation route at higher altitudes. Photodegradation products (CO, HC(O)OH, CF(3)CHO, CF(3)CH(2)OH, and F(2)CO) were identified and also quantified by Fourier transform infrared spectroscopy. CF(3)CH(2)C(O)OH was identified as an end-product as a result of the chemistry involving CF(3)CH(2)CO radicals formed in the OH + CF(3)CH(2)CHO reaction. In the presence of an OH-scavenger (cyclohexane), CF(3)CH(2)C(O)OH was not detected, indicating that channel (R1c) is negligible. Based on a proposed mechanism, our results provide strong evidences of the significant participation of the radical-forming channel (R1a).

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Gas phase UV and IR absorption spectra of CxF2x+1CHO (x = 1–4)

Cited by 19 publications

References 45 publications

The gas phase tropospheric removal of fluoroaldehydes (CxF2x+1CHO, x = 3, 4, 6)

The gas phase tropospheric removal of fluoroaldehydes (CxF2x+1CHO, x = 3, 4, 6)

Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH

UV absorption cross sections between 230 and 350 nm and pressure dependence of the photolysis quantum yield at 308 nm of CF3CH2CHO

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Gas phase UV and IR absorption spectra of CxF2x+1CHO (x = 1–4)

Cited by 19 publications

References 45 publications

The gas phase tropospheric removal of fluoroaldehydes (CxF2x+1CHO, x = 3, 4, 6)

The gas phase tropospheric removal of fluoroaldehydes (CxF2x+1CHO, x = 3, 4, 6)

Atmospheric Lifetimes and Global Warming Potentials of CF3CH2CH2OH and CF3(CH2)2CH2OH

UV absorption cross sections between 230 and 350 nm and pressure dependence of the photolysis quantum yield at 308 nm of CF3CH2CHO

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Atmospheric Lifetimes and Global Warming Potentials of CF₃CH₂CH₂OH and CF₃(CH₂)₂CH₂OH