Kinetics of Cl atom reactions with C sub 2 H sub 6 , C sub 2 H sub 5 , and C sub 2 H sub 4. Rates of disproportionation and recombination of ethyl radicals
- Univ. of Southern California, Los Angeles (USA)
The kinetics of Cl atom reaction with ethane at 298 K were studied with the very low pressure reactor (VLPR). In the very early stages of reaction, with (Cl) > (C{sub 2}H{sub 6}), there is a very fast and irreversible reaction (1), producing HCl + C{sub 2}H{sub 5} followed by a slightly slower reaction (2) of Cl with C{sub 2}H{sub 5} to produce HCl + C{sub 2}H{sub 4}. An extremely slow reaction (4) of Cl with C{sub 2}H{sub 4} to form HCl + C{sub 2}H{sub 3} can also be seen followed by a much faster reaction (5) of Cl with C{sub 2}H{sub 3} to form HCl + C{sub 2}H{sub 2}. After 50% Cl conversion when (Cl) < (C{sub 2}H{sub 6}), only reactions 1 and 3 (the disproportionation of C{sub 2}H{sub 5}) are important. By studying the reaction over large ranges of concentration of both Cl and C{sub 2}H{sub 6}, it is possible to obtain all rate constants except for (5) with good accuracy (cm{sup 3}/molecule {times} s {times} 10{sup 11}): k{sub 1} = 6.10 {plus minus} 0.11, k{sub 2} = 1.21 {plus minus}0.04, k {sub 3} = 0.227 {plus minus}0.006, k{sub 4} = 0.050 {plus minus}0.002. Reaction 2 occurs via an initial recombination that is rate determining and can be described by the recently modified Gorin model for recombination. Ethyl radical disproportionation (3) is well described by a contact-transition-state model. From k{sub 3} and the known ratio for disproportionation to recombination of 0.14 {plus minus}0.01, the rate of recombination of ethyl radical at 298 K is calculated as k{sub r} = (1.62 {plus minus}0.14) {times} 10{sup {minus}11} cm{sup 3}/molecule {times} s = (9.7 {plus minus}.8) {times} 10{sup 9} L/mol {times} s.
- OSTI ID:
- 6835118
- Journal Information:
- Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:3; ISSN 0002-7863; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ALKANES
ALKYL RADICALS
ATMOSPHERIC CHEMISTRY
CHEMISTRY
CHLORINE
DATA
DATA ANALYSIS
ELEMENTS
ETHANE
ETHYL RADICALS
EXPERIMENTAL DATA
HALOGENS
HYDROCARBONS
INFORMATION
KINETICS
LOW PRESSURE
MEASURING INSTRUMENTS
MEASURING METHODS
MEDIUM TEMPERATURE
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OZONE
RADICALS
REACTION KINETICS
RECOMBINATION