Application of time-resolved infrared spectroscopy to the determination of absolute rate constants for Cl + C{sub 2}H{sub 6} and Cl + C{sub 2}H{sub 5}Cl
- Ford Motor Company, Dearborn, MI (United States)
- Univ. of Akron, OH (United States)
Time-resolved infrared spectroscopy (TRISP) has been used to determine at 700 Torr and 298 K the absolute rate constants of reactions (1) Cl + C{sub 2}H{sub 6} = C{sub 2}H{sub 5} + HCl [k{sub 1} = 7.05({+-}1.4) x 10{sup {minus}11} cm{sup 3}/molecule s] and (2) Cl + C{sub 2}H{sub 5}Cl = C{sub 2}H{sub 4}Cl + HCl [k{sub 2} = 6.8({+-}1.4) x 10{sup {minus}12} cm{sup 3}/molecule s]. Absolute rate constants were measured by observing the rate of HCl production using this pulsed, broad-band IR technique for time delays from 50 ns to 10 {mu}s after the photolysis laser pulse. Because chain propagation occurs via reactions (4) C{sub 2}H{sub 5} + Cl{sub 2} = C{sub 2}H{sub 5}Cl + Cl or (6) C{sub 2}H{sub 4}Cl + Cl{sub 2} = C{sub 2}H{sub 4}Cl{sub 2} + Cl, corrections for these reactions were included in the absolute rate calculations. A determination of the rate constant of reaction 6 relative to reaction 5, C{sub 2}H{sub 4}Cl + O{sub 2} = C{sub 2}H{sub 4}ClO{sub 2}, was required to calculate k{sub 2}. The ratio k{sub 6}/k{sub 5} was measured at 700 Torr by continuous UV photolysis of Cl{sub 2}, O{sub 2}, and C{sub 2}H{sub 5}Cl mixtures in a static reactor using the relative rate technique. Values of k{sub 6}/k{sub 5} = 0.42 ({+-}0.06) and 0.63 ({+-}0.15) were obtained for 1-chloroethyl and 2-chloroethyl radicals, respectively. The measured value of k{sub 1} agrees with previous low-pressure (<10 Torr) determinations verifying that reaction 1 is pressure independent.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 563391
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 1 Vol. 96; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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