Gas phase radiation chemistry of pentafluoroethyl iodine

Hsieh, Tacheng; Hanrahan, Robert J.

doi:10.1016/0146-5724(78)90073-0

Cited by 2 publications

(5 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5 Torr. The lack of CF4 confirms that it is not a primary dissociation product (as predicted), and that reaction [8] is effectively eliminated when Hz is added. Some of the trifluoromethyl radicals formed in IRMPD may be scavenged by the hydrogen donor as follows:…”

Section: Hydrogen Donorsmentioning

confidence: 49%

“…At higher fluence (13.4 J ~m -~, 200 pulses) the increase in the relative yield at 2 Torr is 2.5 times that at 1 Torr. Reaction [8] therefore becomes more dominant as the pressure of C2F6 is increased, especially at low fluence where less secondary photolysis of 'CF3 has occurred. Reactions similar to [8] have been proposed in the radiolysis of pentafluoroethyl iodide (8) and trifluoromethyl iodide (9).…”

Section: P'mentioning

confidence: 99%

“…Reaction [8] therefore becomes more dominant as the pressure of C2F6 is increased, especially at low fluence where less secondary photolysis of 'CF3 has occurred. Reactions similar to [8] have been proposed in the radiolysis of pentafluoroethyl iodide (8) and trifluoromethyl iodide (9). 'C2F5 may then react with 'CF3 to form C3Fs, reaction [9], or recombine to form decafluorobutane, reaction [lo].…”

Section: P'mentioning

confidence: 99%

“…reaction [8] does not occur in the presence of a hydrogen donor). Thus we propose that a second dissociation pathway [3] must also be occurring:…”

Section: Hydrogen Donorsmentioning

confidence: 99%

“…excited 'CF, from the parent C2F6 as follows: [8] 'cF~' + C2F6 + CF4 + 'C2F5 This reaction should be about 17 kJ/mol exothermic. It should be noted that in experiments done using the 9R(30) C 0 2 laser pump line, the relative yield of CF4/C2F4 increases as the pressure of C2F6 is increased from 1 to 2 Torr.…”

Section: P'mentioning

confidence: 99%

See 4 more Smart Citations

The infrared multiphoton dissociation of hexafluoroethane

Brown¹,

Smith²

1988

Can. J. Chem.

View full text Add to dashboard Cite

. ' The infrared multiphoton dissociation of hexafluoroethane. Can. J. Chem. 66, 609 (1988). The infrared multiphoton dissociation (IRMPD) of "neat" hexafluoroethane has been investigated for the first time. The stable products of photolysis are CF4, C2F4, C3F8, and C4FI0. Product analysis involved tunable diode laser (TDL) and fourier transform infrared spectroscopy, as well as gas chromatography where applicable. The high sensitivity and resolution of the TDL allows for measurement of the stable products CF4 and C2F4 after irradiation by a single infrared laser pulse. The yield of .CF3 radicals produced by the IRMPD of C2F6 as a function of fluence was measured via the TDL high frequency modulation technique. The role of added H2, leading to elimination of CF4 and increase of C2F4 as products, is clarified. CARL E. BROWN et DONALD R. SMITH. The infrared multiphoton dissociation of hexafluoroethane. Can. J. Chem. 66, 609 (1988). On a CtudiC pour la premikre fois la dissociation multiphotonique infrarouge (DMPIR) de I'hexafluoroCthane 1'Ctat pur. Les produits stables de la photolyse sont le CF4, le C2F4, le C3F8 et le C4FI0. Dans les cas ou ces techniques pouvaient &tre appliqukes pour l'analyse des produits, on a utilisC un laser a diode ajustable (LDA), la spectroscopie infrarouge par transformation de fourier ainsi que la chromatographie en phase gazeuse. La sensibilitC ClevCe et la grande rCsolution du LDA permettent de mesurer les produits stables, comme le CF4 et le C2F4, aprks une irradiation par une seule pulsation du laser infrarouge. On a utilisC la technique de modulation de la haute frCquence du LDA pour mesurer le rendement en radicaux 'CF3 produits par DMPIR du C2F6, en fonction de la fluiditC. On a Cclairci le r81e du Hz ajoutC sur I'Climination de CF4 et l'augmentation du C2F4. comme produits de la rtaction.[Traduit par la revue] Introduction In earlier work Fisk (I) reported C2F4 and CHF3 as the products of the infrared multiphoton dissociation (IRMPD) of hexafluoroethane in the presence of Hz or C6H14. Several years later Arai et al. (2) studied the IRMPD of hexafluoroethane in the presence of Br2, the results of their experiments indicated that the major reaction products were CF3Br and CF2Br2. Our exploratory work on the IRMPD of "neat" hexafluoroethane showed that CF4 was the major photolysis product, with lesser amounts of C2F4, C3F8, and C4F10 Thermodynamically, the most favourable dissociation pathway of C2F6 leads to the production of CF4 and :CF2. However, shock tube studies (3) suggest that this pathway possesses a large energy barrier. The next most favourable pathway is the result of C 4 bond scission forming two 'CF3 radicals, reaction [2]. Presumably the pre-exponential factor favours reaction [2] as well, since it only involves C 4 bond breakage.

show abstract

Section: Hydrogen Donorsmentioning

confidence: 49%

Section: P'mentioning

confidence: 99%

Section: P'mentioning

confidence: 99%

“…reaction [8] does not occur in the presence of a hydrogen donor). Thus we propose that a second dissociation pathway [3] must also be occurring:…”

Section: Hydrogen Donorsmentioning

confidence: 99%

Section: P'mentioning

confidence: 99%

See 3 more Smart Citations

The infrared multiphoton dissociation of hexafluoroethane

Brown¹,

Smith²

1988

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

Measurement of kinetic parameters relevant to the operation of an electron-beam initiated atomic iodine laser

Ramírez

Bera

Hanrahan

1985

Journal of Applied Physics

View full text Add to dashboard Cite

Parameters relevant to the operation of an electron-beam initiated atomic iodine laser, which would lase on the transition 5 2P1/2 (I*)→5 2P3/2 (I), have been measured by pulse radiolysis. Kinetic data for the parent compound quenching of I* were obtained by variation of the parent compound pressure at constant buffer gas pressure and observing I* decay rates versus time. Deactivation rates for perfluoroalkyl iodides were found to be much lower than for the corresponding alkyl iodides. Values obtained (in cm3 molec−1 s−1) are as follows: CH3I, (2.0±0.1)×10−13; C2H5I, (5.0±0.3)×10−13; CF3I, (8.8±0.3)×10−16; C2F5I, (9.7±1.0)×10−15; n-C3F7I, (2.5±0.2)×10−15; i-C3F7I, (1.7±0.1)×10−15; n-C4F9I, (1.8±0.1)×10−14. The extent of population inversion was investigated by measuring initial excited state and ground state atomic iodine concentrations, which gives the branching ratio [I*]/[I]. Values obtained are as follows: CH3I, 2.7; CF3I, 3.8; C2F5I, 2.7; i-C3F7I, 3.2; n-C4F9I, 1.8. Comparing both branching ratios and lifetimes, it is seen that CF3I is the most promising candidate for an electron beam initiated atomic iodine laser.

show abstract

Gas phase radiation chemistry of pentafluoroethyl iodine

Cited by 2 publications

References 35 publications

The infrared multiphoton dissociation of hexafluoroethane

The infrared multiphoton dissociation of hexafluoroethane

Measurement of kinetic parameters relevant to the operation of an electron-beam initiated atomic iodine laser

Contact Info

Product

Resources

About