Exploration of Ozonolysis in Multiple Media

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With this award, the Organic and Macromolecular Chemistry Program supports the work of Professor Neil M. Donahue of Carnegie-Mellon University. This research will probe the basic reaction dynamics controlling ozonolysis reactions between unsaturated hydrocarbons and ozone in the gas phase and on cold surfaces. The factors which control which bonds break when the primary ozonide, formed when ozone reacts with alkene double bonds, breaks up and what controls the exact structure of the resulting reaction products will be determined. By combining computational studies with experimental kinetics in multiple phases, the research will isolate factors potentially responsible for governing the chemical behavior of ozone-alkene reactions. By studying both cycloalkenes, where the reaction products are tethered and the reaction energy thus resides entirely in a single fragment, and non-cyclic alkenes, which yield two fragments that each possess a distribution of energies, the research will reveal details of collisional energy transfer and the energy distribution among the reaction fragments.Among the broader impacts of this research is its impact in learning about air pollution. Ozonolysis is responsible for significant radical production in urban and regional atmospheric chemistry; it thus plays a central role in photochemical smog formation. It is also a major source of ultrafine organic aerosols, which are a significant health hazard. Consequently, understanding the mechanistic details of ozonolysis is vital to developing control strategies for urban air quality. Aerosol generation initiated when ozone invades buildings and reacts with various household and industrial solvents is also a significant public health concern. These issues will serve as a cornerstone for curricular development revolving around an ozonolysis demonstration suitable for both public and undergraduate education. Also important is the training of young scientists in an area where basic fundamental chemical studies will have a significant impact on a problem of considerable concern to the public.