Explicit photochemical mechanism for atmospheric oxidation of n-butane

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:5509768

Wen, L

Alkanes, being an important component of atmosphere, serve as precursors to ozone formation in urban and rural air masses. An explicit photochemical oxidation mechanism for n-butane, which is the major hydrocarbon component of automobile exhaust, is created in this work. The yields of organic nitrates from n-butane, n-pentane, and methyl ethyl ketone photooxidations were studied in Teflon bag and smog chamber experiments. Comparing with the expression currently using the most atmospheric model studies, the total butyl nitrates yield obtained in this work is about 36% lower, and the ratio of primary to secondary butyl nitrates is slightly higher. It is shown in this work that the yields of hydroxyl and carbonyl butyl nitrates are very low, and can be ignored in the explicit photochemical mechanisms. The explicit photochemical oxidation mechanism for methyl ethyl ketone (MEK) was created first because it is the major product from photooxidation of n-butane. The explicit photochemical oxidation mechanism for n-butane, created later, draws on the MEK mechanism. The mechanisms were tested by comparing model predictions with experimental observations from smog chamber experiments. The comparisons were conducted for species which had experimental observation data, such as O[sub 3], NO, and NO[sub 2], n-butane, MEK, organic nitrates, and aldehydes species. The sixteen smog chamber experiments, used in model simulations, were conducted during 1978 to 1992. The mechanisms are mainly based on the available kinetic data in literature and the experimental result in this work. The rate constants for some reactions in the mechanisms were adjusted to make a better fit with the experimental observations. These reactions were: reaction of OH and n-butane to form secondary butyl peroxy radical, decomposition of secondary butoxy radical, and reaction of OH and MEK.

• Research Organization: North Carolina Univ., Chapel Hill, NC (United States)
• OSTI ID: 5509768
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BUTANE
OXIDATION
PHOTOCHEMICAL REACTIONS
EXHAUST GASES
PHOTOCHEMICAL OXIDANTS
ALDEHYDES
ALKANES
ATMOSPHERIC CHEMISTRY
AUTOMOBILES
NITRATES
OZONE
PENTANE
SMOG
CHEMICAL REACTIONS
CHEMISTRY
FLUIDS
GASEOUS WASTES
GASES
HYDROCARBONS
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
VEHICLES
WASTES
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)
400500 - Photochemistry