Quantum yield of photolysis of perfluoroacetyl fluoride vapour: possible source of CF3 radicals

Weibel, Daniel Eduardo; Vöhringer, Cecilia M. de; Staricco, E. H.; Staricco, Esther R. de

doi:10.1016/1010-6030(92)85146-l

Cited by 12 publications

(4 citation statements)

References 20 publications

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“…Judging from the experimental results previously reported, 39 which show that the amounts of CF 4 observed through the photolysis of CF 3 CFO followed by product analysis are three orders of magnitude less than the quantities of the other products (CO, C 2 F 6 and CF 2 O), a potential barrier difficult to overcome at room temperature exists in the reaction CF 3 + FCO -CF 4 + CO. In contrast, we could not find any transition states connected with the formation of a pair of CF 3 and FCO.…”

Section: Formation Mechanisms Of Cmentioning

confidence: 71%

Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF₄/O₂plasmas

Furuya

Ide

Okumura

et al. 2009

Phys. Chem. Chem. Phys.

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Mass analysis has been conducted on the positive ions and neutral species in the downstream region of Ar/CF(4)/O(2) plasmas. The neutral species have been ionized by Li(+) attachment before mass analysis. The CF(2)O(+), C(2)F(5)O(+) and C(n)F(2n-1)O(+) (1 or= 4) have been observed as the species composed only of C and F. These findings suggest that C(n)F(2n)O (n>or= 3) are produced mainly through the following reactions: CF(3)(CF(2))(m)CF = CF(2) + O((3)P) --> CF(2)((3)B(1)) + CF(3)(CF(2))(m)CFO (m>or= 1) and CF(3)(CF(2))(m)CF = CF(CF(2))(n)CF(3) + O((3)P) --> CF(3)(CF(2))(m)CF + CF(3)(CF(2))(n)CFO (m, n>or= 1), where the CF(3)(CF(2))(n)- group might have side chains, as in (CF(3))(2)CF(CF(2))(n-2)-. With the help of quantum chemistry calculations of reaction enthalpies and transition states, the formation mechanisms of the observed species have been discussed in detail.

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Section: Formation Mechanisms Of Cmentioning

confidence: 71%

Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF₄/O₂plasmas

Furuya

Ide

Okumura

et al. 2009

Phys. Chem. Chem. Phys.

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“…The region of the atmosphere where CF 3 C(O)F is formed will influence its degradation and end‐product yields, i.e., the potential formation of CF 4 . In the stratosphere, CF 3 C(O)F is expected to be removed primarily by short‐wavelength UV photolysis [ Weibel et al , ; Bierbrauer et al , ; Sander et al , ]:

{normalC normalF}_{3} normalC ((), O) normalF + normalh v \to \overset{C}{true} F_{3} + normalF \overset{C}{true} normalO ~ 300 normalnm

\to {normalC normalF}_{3} \overset{C}{true} normalO + normalF ~ 231 normalnm

\to \overset{C}{true} F_{3} + normalC normalO + normalF ~ 219 normalnm

\to {normalC normalF}_{4} + normalC normalO All λ

where the photodissociation thresholds at 298 K were calculated using the heats of formation from Sander et al []. In the troposphere, CF 3 C(O)F will hydrolyze within weeks and produce trifluoroacetic acid, CF 3 C(O)OH, a persistent pollutant [ Henne et al , ; WMO , ; Burkholder et al , ].…”

Section: Introductionmentioning

confidence: 99%

An atmospheric photochemical source of the persistent greenhouse gas CF₄

Jubb

McGillen

Portmann

et al. 2015

Geophysical Research Letters

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A previously uncharacterized atmospheric source of the persistent greenhouse gas tetrafluoromethane, CF4, has been identified in the UV photolysis of trifluoroacetyl fluoride, CF3C(O)F, which is a degradation product of several halocarbons currently present in the atmosphere. CF4 quantum yields in the photolysis of CF3C(O)F were measured at 193, 214, 228, and 248 nm, wavelengths relevant to stratospheric photolysis, to be (75.3 ± 1) × 10−4, (23.7 ± 0.4) × 10−4, (6.6 ± 0.2) × 10−4, and ≤0.4 × 10−4, respectively. A 2‐D atmospheric model was used to estimate the contribution of the photochemical source to the global CF4 budget. The atmospheric photochemical production of CF4 from CF3CH2F (HFC‐134a), CF3CHFCl (HCFC‐124), and CF3CCl2F (CFC‐114a) per molecule emitted was calculated to be (1–2.5) × 10−5, 1.0 × 10−4, and 2.8 × 10−3, respectively. Although CF4 photochemical production was found to be relatively minor at the present time, the identified mechanism demonstrates that long‐lived products with potential climate impacts can be formed from the atmospheric breakdown of shorter‐lived source gases.

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“…To our knowledge, no photochemistry study of acetyl fluoride has been reported, the closest analogy is provided by CF 3 C(O)F. 40,41 In the more recent work by Bierbrauer et al, 41 the C−C bond cleavage of CF 3 C(O)F has been concluded to occur with unity quantum yield at 254 nm. Note that the overall QY of photolysis of acetone is unity at 248 nm (see, e.g., ref 42 and references therein).…”

Section: Resultsmentioning

confidence: 95%

Gyűrűs éterek és észterek környezeti kémiája: reakciókinetikai és fotokémiai kutatások

Illés¹

2019

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Second generation (2G) biofuels are produced from non-edible lignocellulosic biomass providing sustainable alternatives for fossil fuels. The OH reaction rate constant has been determined for the 2G biofuel ethyl levulinatefor the first time. The direct reaction kinetic technique of pulsed laser photolysis (PLP) coupled with resonance fluorescence (RF) detection of OH radicals has been used to determine the rate constant value of k 1 = (3.43 ± 0.36) 9 10 -12 cm 3 molecule -1 s -1 (298 K), where the error given designates 2r accuracy. Implications for atmospheric chemistry have been discussed.

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Quantum yield of photolysis of perfluoroacetyl fluoride vapour: possible source of CF3 radicals

Cited by 12 publications

References 20 publications

Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF₄/O₂plasmas

Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF₄/O₂plasmas

An atmospheric photochemical source of the persistent greenhouse gas CF₄

Gyűrűs éterek és észterek környezeti kémiája: reakciókinetikai és fotokémiai kutatások

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Quantum yield of photolysis of perfluoroacetyl fluoride vapour: possible source of CF3 radicals

Cited by 12 publications

References 20 publications

Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF4/O2plasmas

Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF4/O2plasmas

An atmospheric photochemical source of the persistent greenhouse gas CF4

Gyűrűs éterek és észterek környezeti kémiája: reakciókinetikai és fotokémiai kutatások

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Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF₄/O₂plasmas

Mass spectrometric investigation and formation mechanisms of high-mass species in the downstream region of Ar/CF₄/O₂plasmas

An atmospheric photochemical source of the persistent greenhouse gas CF₄