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Title: | KINETICS OF GASEOUS REACTIONS OF THE HYDROXYL RADICAL WITH SELECTED CYCLOALKENES AND AROMATIC COMPOUNDS |
Authors: | Kimura, Takako |
Advisor: | Yarwood, A.J. |
Department: | Chemistry |
Keywords: | Chemistry;Chemistry |
Publication Date: | Oct-1986 |
Abstract: | <p>The kinetics of the OH radical reactions with selected cycloalkenes and aromatic compounds were studied in the gas phase with the flash photolysis-resonance fluorescence technique. Five OH-cycloalkene reactions were studied at temperatures between 295 and 428 K. The significance of the allylic hydrogen abstraction process relative to the addition process in these reactions is discussed. On the basis of the room-temperature rate constants, the significance of the OH radical reactions with cycloalkenes in the troposphere is considered. Arrhenius parameters were calculated for each reaction. The reactions all have negative apparent activation energies of $\sim4 - 5$ kJ mol$\sp{-1}$; values similar to those of OH-alkene reactions. The factors which might determine the relative reactivity of various OH-alkene and OH-cyclo-alkene reactions are examined. The kinetics of the OH-benzene reaction were studied at temperatures between 295 and 425 K. The validity of the previously proposed mechanism and the reasons for the discrepancies among the studies reported in the literature are examined by comparing the observed kinetics with the predictions of computer simulation of the mechanism. The temperature dependence of the OH-chlorobenzene reaction was studied in the same temperature range, and the kinetics were compared with those of the OH-benzene reaction. The OH radical reactions were also studied at room temperature with six selected halogenated benzenes and biphenyl. The factors which might determine the relative reactivity of these reactions and other previously reported OH-aromatic reactions are discussed. The rate constants of various OH-chlorinated benzene reactions at room temperature were used as a model to estimate the relative reactivity of the OH-polychlorinated biphenyl reactions, and to discuss the significance of the reactions in determining the atmospheric lifetimes of polychlorinated biphenyls.</p> |
URI: | http://hdl.handle.net/11375/8228 |
Identifier: | opendissertations/3449 4466 1631172 |
Appears in Collections: | Open Access Dissertations and Theses |
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fulltext.pdf | 4.78 MB | Adobe PDF | View/Open |
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