Gas Phase Oxidation of Resonance-Stabilized Radicals

West Virginia University Research Corporation, Morgantown WV

Investigators

Abstract

In this project, funded by the Chemical Structure, Dynamics and Mechanisms B Program of the Chemistry Division and by NSF EPSCoR, Professor Fabien Goulay from the Department of Chemistry at West Virginia University investigates combustion reaction mechanisms. The central focus is on the oxidation of large, stable free radicals which can accumulate in combustion environments. These intermediates are known to play a major role during the formation of pollutants such as polycyclic aromatic hydrocarbons (PAHs) and particulate matter. Gas phase and high temperature reactions are investigated both experimentally and computationally. Experimental studies employ spectroscopic methods to characterize intermediates and their chemical behavior. This research provides critical information on reaction mechanisms that will be used to develop more efficient combustion processes for transportation and power generation. This project also provides training opportunities for undergraduate and graduate students, including first generation college students and students from the Appalachian region, who have been traditionally underrepresented in the sciences. The project investigates the oxidation of resonance-stabilized radicals in the gas phase. These radicals can build up in appreciable concentrations and have recently been hypothesized as precursors to polycyclic aromatic hydrocarbons and soot. The concentration of these radicals in the gas phase is depleted mostly by oxidation reactions with very reactive species, such as the hydroxyl radical. Although theoretical studies have been performed to predict their reactivity toward the hydroxyl radicals, no experimental data are available to validate these predictions. The experimental study of radical - radical reactions is difficult because both radicals need to be formed simultaneously at sufficient concentrations. Professor Goulay and his Group produce both radicals in a flow reactor using laser photolysis, and detect their concentrations using laser spectroscopy and mass spectrometry. Theoretical calculations are used to analyze the reaction mechanisms. This work also contributes to the career development of future scientists by providing training at state-of-the-art experimental resources, including synchrotron facilities. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.