Investigation of radical reactions in C2Cl4 and C2Cl4/O2 discharges by EPR, mass, and emission spectroscopy

Breitbarth, F. W.; Rottmayer, S.

doi:10.1007/bf00565551

Cited by 13 publications

(3 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…'s rate coefficients seems a little low compared to values one might expect based on our measurements in N 2 buffer gas, and the ratio k 1 (100 Torr of He)/ k 1 (15 Torr of He) = 1.25 obtained from Davis et al's results is smaller than one would predict based on the 297 K falloff curve we have obtained using N 2 as the buffer gas (Figure ). Breitbarth and Rottmayer have employed a discharge flow system with an EPR detector to study the kinetics of the O( 3 P J ) + C 2 Cl 4 reaction at 298 K and 0.3 Torr total pressure in O 2 buffer gas …”

Section: Resultsmentioning

confidence: 99%

“…Comparison of available kinetic data for the OH + C 2 Cl 4 reaction − with available data for the Cl( 2 P J ) + C 2 Cl 4 reaction − suggests that the Cl( 2 P J ) + C 2 Cl 4 rate coefficient is several hundred times faster than the OH + C 2 Cl 4 rate coefficient at tropospheric temperatures and pressures. Until recently, it has been thought that chlorine atom levels in the troposphere were so low that Cl( 2 P J ) could not be an important tropospheric reactant.…”

Section: Introductionmentioning

confidence: 99%

“…While numerous kinetics studies of reaction 1 have been reported, − the temperature and pressure dependences of the rate coefficient have not been systematically investigated. In this paper we report the results of experiments where laser flash photolysis of Cl 2 /C 2 Cl 4 /N 2 mixtures has been coupled with Cl( 2 P J ) detection by time-resolved atomic resonance fluorescence spectroscopy to investigate the kinetics of reaction 1 over the temperature range 231−298 K and the pressure range 3−700 Torr; over this range of experimental conditions the reaction is found to be in the falloff regime between third and second order, although the high-pressure second-order limit is approached at the low-temperature and high-pressure limits of the range of conditions investigated.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetics and Thermochemistry of the Cl(²P_J) + C₂Cl₄ Association Reaction

et al. 1996

View full text Add to dashboard Cite

A laser flash photolysis-resonance fluorescence technique has been employed to study the kinetics of the Cl( 2 P J ) + C 2 Cl 4 association reaction as a function of temperature (231-390 K) and pressure (3-700 Torr) in nitrogen buffer gas. The reaction is found to be in the falloff regime between third and second order over the range of conditions investigated, although the second-order limit is approached at the highest pressures and lowest temperatures. At temperatures below 300 K, the association reaction is found to be irreversible on the experimental time scale of ∼20 ms. The kinetic data at T < 300 K have been employed to obtain falloff parameters in a convenient format for atmospheric modeling. At temperatures above 330 K, reversible addition is observed, thus allowing equilibrium constants for C 2 Cl 5 formation and dissociation to be determined. Second-and third-law analyses of the equilibrium data lead to the following thermochemical parameters for the association reaction: ∆H°2 98 ) -18.1 ( 1.3 kcal mol -1 , ∆H°0 ) -17.6 ( 1.3 kcal mol -1 , and ∆S°2 98 ) -27.7 ( 3.0 cal mol -1 K -1 . In conjunction with the well-known heats of formation of Cl( 2 P J ) and C 2 Cl 4 , the above ∆H values lead to the following heats of formation for C 2 Cl 5 at 298 and 0 K: ∆H°f ,298 ) 8.0 ( 1.3 kcal mol -1 and ∆H°f ,0 ) 8.1 ( 1.5 kcal mol -1 . The kinetic and thermochemical parameters reported above are compared with other reported values, and the significance of reported association rate coefficients for understanding tropospheric chlorine chemistry is discussed. † Present address: Cl 2 + hν (355 nm) f nCl( 2 P 3/2 ) + (2n)Cl( 2 P 1/2 ) (2) ln{[Cl( 2 P J )] 0 /[Cl( 2 P J )] t } ) (k 1 [C 2 Cl 4 ] + k 3 )t ) k′t (I)

show abstract

Section: Resultsmentioning

confidence: 99%