Kinetic isotope effects in the gas-phase reaction of hydroxyl radicals with ethylene in the temperature range 343-1173 K and at 1-atm pressure

Journal Article · Thu Jun 30 04:00:00 EDT 1988 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100324a029· OSTI ID:6478915

Liu, A; Mulac, W A; Jonah, C D

The rates of the reaction of ethylene and ethylene-d/sub 4/ with OH and OD were determined. The following reactions were examined: OH + C/sub 2/H/sub 4/ ..-->.. products (HH); OD + C/sub 2/H/sub 4/ ..-->.. products (DH); OH + C/sub 2/D/sub 4/ ..-->.. products (HD); OD + C/sub 2/D/sub 4/ ..-->.. products (DD). These reactions show different reaction pathways at different temperatures. Below 560 K there is a weak negative activation energy which is characteristic of the OH addition to the double bond. k/sub HH/ and K/sub HD/ were the same at 1.65 x 10/sup -12/ exp(480/T) cm/sup 3//(molecule s) while k/sub DD/ and k/sub DH/ were the same at 1.35 x 10/sup 12/ exp(480/T) cm/sup 3//(molecule s). Above 720 K, all rate constants show a positive activation energy of 4-5 kcal/mol and both primary and secondary kinetic isotope effects were observed. The high-temperature pathway was attributed to the H abstraction from ethylene by the OH. A conventional transition-state-theory calculation (TST) successfully reproduced the temperature and isotope dependence of the H abstraction rate constants.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6478915
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 92:13; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
ALKENES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DEUTERIUM COMPOUNDS
ENERGY
ETHYLENE
FLUIDS
GASES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXYL RADICALS
ISOTOPE EFFECTS
KINETICS
ORGANIC COMPOUNDS
RADICALS
REACTION KINETICS
TEMPERATURE DEPENDENCE