With the support of the Organic Dynamics Program in the Chemistry Division, Professor Barney Ellison at the University of Colorado at Boulder will explore the reactivity of hydrocarbon films at a solid/gas interface and at a liquid/gas interface. These experiments are aimed at the identification of reactive radicals that mediate the oxidation of hydrocarbon films. Alkylperoxyl radicals, ROO, will be produced that must be thoroughly characterized. Ellison plans to use hyperthermal supersonic jets to produce beams of the CH3CH2 radical and to generate matrix-isolated ethylperoxyl radicals, CH3CH2OO. The polarized infrared spectroscopy of matrix-isolated EtOO radicals will be completely studied. An important fate of aerosol-bound peroxyl radicals will be reaction with NO followed by either fragmentation to NO2 and an alkoxy radical, or isomerization to an alkyl nitrate. Consequently, Ellison proposes to produce the CH3OO-NO adduct in a matrix and use an FTIR to explore its properties. In collaboration with Dr. D. Ray at the DOE's EMSL labs, Ellison will use a Ti:Sapphire laser to detect surface-bound peroxyl radicals at a liquid/atmospheric pressure interface via the non-linear optical process of second harmonic generation (SGH). The SHG experiment will search for ROO radicals at an interface between an aqueous solution and air. In collaboration with Prof. B. Koel at USC, Professor Ellison plans to explore the oxidation of alkene films with O3 and to study the mechanisms of olefin oxidation with O3 at an interface. In the study of O3 with olefin films, Ellison & Koel will produce samples of the simplest Criegee intermediate, CH2OO, and study it in matrices using FITR. Experimental studies of the sort proposed here will provide a basis for theorists to predict and model real aerosols and to understand the oxidation mechanisms of hydrocarbon films in the environment.
The Organic and Macromolecular Chemistry Program supports Professor Barney Ellison at the University of Colorado at Boulder who has a long history of joint research efforts with other chemists. Ellison's lab collaborates regularly with atmospheric chemists at NOAA's Aeronomy Labs and the NSF's NCAR labs. The inverted micelle model was a collaboration with V. Vaida (University of Colorado) and A. Tuck (NOAA) and was inspired by NOAA's field data. Ellison continually works with chemists studying biomass burning at the DOE's NREL labs in Golden, CO and with surface chemists at the DOE's EMSL labs in Richmond, WA and at USC in Calif. All of these groups are pursuing hypercomplex chemical problems having to do with the tropospheric fate of volatile organic compounds (VOCs), the chemical analysis and dynamics of organic aerosols in the atmosphere, and the chemical and spectroscopic properties of gas/solid and gas/liquid interfaces. Ellison and his students provide these labs with an "organic chemistry point-of-view."
