title: Kinetics and thermodynamics of atmospherically relevant aqueous phase reactions of α-pinene oxide.
abstract: Recent work has demonstrated that isoprene-derived epoxide intermediates are responsible for a wide variety of chemical species found in ambient secondary organic aerosol (SOA). Since the second most abundant biogenic hydrocarbon, α-pinene, is also known to form an epoxide intermediate, nuclear magnetic resonance techniques were used to study products, kinetics, and equilibria of the aqueous phase reactions of that epoxide, α-pinene oxide. The present results indicate that α-pinene oxide will react very quickly with aqueous atmospheric particles, even under low acidity conditions. Depending on the acid concentration of the aqueous solutions, a number of new products are observed from the reaction of α-pinene oxide, some of which are expected to partition back to the gas phase. In contrast to some previous results, no long-lived organosulfate or organonitrate species are observed, and no species which retain the α-pinene bicyclic carbon backbone are observed. Rather, the overall product distribution can be explained by various rearrangements of the initial carbocation intermediate formed in the ring opening of α-pinene oxide, all of which can be rationalized by the thermodynamically driven relief of the bicyclic ring strain in the α-pinene carbon backbone.
authors.affiliation: Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, USA.
authors.forename: Dylan B
authors.initials: DB
authors.lastname: Bleier
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Elrod
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D000081008:Bicyclic Monoterpenes; D007700:Kinetics; D015394:Molecular Structure; D011789:Quantum Theory; D013729:Terpenes / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D000081008:Bicyclic Monoterpenes; D013729:Terpenes; D014867:Water; C053997:2-pinene oxide