Organic Chemistry in Harsh Reaction Environments

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

In this project funded by the Chemical Structure, Dynamics & Mechanism B Program of the Chemistry Division, Professor Robert J. McMahon of the Department of Chemistry at the University of Wisconsin-Madison will investigate the behavior of organic compounds under harsh conditions of temperature, pressure, or radiation. These conditions, which are similar to the conditions found in flames (combustion) or in space, cause the degradation of organic compounds and generate a complex mixture of highly reactive products. The proposed research will explore the chemical properties and chemical reactions of these reactive molecules. This research provides a foundation for understanding two very different problems: one involving combustion and another involving the chemistry of space. Combustion of organic fuels is central to our nation's energy supply and national economy. A fundamental understanding of combustion offers the possibility of enhancing the energy efficiency of fuel combustion and minimizing pollutants (soot) that arise from incomplete combustion. In interstellar space, it is now known that hundreds of different organic compounds exist throughout the galaxy in environments that are harsh because they are so hot (near stars) or because they are so cold (far from stars). Studying these environments is a crucial step in understanding the distribution of organic material in the universe and identifying molecules that could be precursors to life. Professor McMahon and his coworkers will also continue their engagement in a variety of science education and outreach activities. The fundamental chemical studies proposed herein would not have been possible only a few years ago. Tremendous advances in both experimental and computational techniques now permit the analysis and interpretation of the experimental spectra obtained from complex mixtures of reactive species. Direct studies of these species are challenging because these molecules typically exhibit high reactivity. Nevertheless, it is the reaction chemistry of these ephemeral intermediates that governs the chemical behavior of the system. In combustion chemistry, the determination of accurate equilibrium structures of reactive intermediates will provide important benchmarks for prototypical molecules, and theory can be further used to establish thermodynamic parameters that are important for modeling. In astrochemistry, the Atacama Large Millimeter / sub-millimeter Array (ALMA), an astronomical interferometer of radio telescopes in the Atacama Desert of northern Chile completed in 2013, is generating a deluge of new radio-astronomical data. These data can be interpreted only by comparison with laboratory spectra of the type that will be obtained through the proposed studies.