title: Mechanisms and reaction-path dynamics of hydroxyl radical reactions with aromatic hydrocarbons: the case of chlorobenzene.
abstract: All geometries and energies significant for the first step of tropospheric degradation of chlorobenzene were characterized using the MP2/6-31+G(d,p) and G3 methods. A pre-reaction complex for the addition of OH radical to chlorobenzene was found and the associated transition state was determined for the first time. The reaction path for the association of OH radical and chlorobenzene into the pre-reaction complex was extrapolated from the selected low frequency normal mode of pre-reaction complex. The reaction rate constant for addition of OH radical to chlorobenzene was determined for the temperature range 230-330K, using RRKM theory and G3 energies. The calculated rate constants are in agreement with the experimental results. Regioselectivity was also determined for the title reaction from the ratio of respective reaction rates and our results are in very good agreement with the experimental results, which show the dominance of the ortho and para channels as well as a negligible contribution by the ipso channel.
authors.affiliation: Institute Rudjer Boskovic, POB 180, HR-10002 Zagreb, Croatia.
authors.forename: Goran
authors.initials: G
authors.lastname: Kovacevic
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Sabljic
mesh_terms: D000393:Air Pollutants / Q000737:chemistry; D002722:Chlorobenzenes / Q000737:chemistry*; D006841:Hydrocarbons, Aromatic / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical
chemical_list: D000393:Air Pollutants; D002722:Chlorobenzenes; D006841:Hydrocarbons, Aromatic; D017665:Hydroxyl Radical; C031294:chlorobenzene