Quantifying Stereochemical Differences in Alkyl-Substituted Cyclic Ethers

Developing advanced combustion technologies for transportation relies on understanding details of chemical reactions that take place during combustion. Engineers use computer models to simulate combustion processes to design and manage them efficiently. However, understanding the details of the chemistry and rates of reactions is required for accurate models. The reactions involve many short-lived, but important, chemical intermediates. When information about the intermediates is unavailable, the accuracy of computer models can suffer. This project will conduct experiments involving a group of intermediates that form during combustion of certain fuels. It will use spectroscopic methods to analyze how the molecular structures of the intermediates influence combustion, including ignition. The outcomes of the project will be data that can improve computer modeling for applications such as internal combustion engines and aviation fuel development. This project will conduct the first set of experiments on a group of six constitutional isomers and stereoisomers for 3-membered and 4-membered cyclic ethers, which are important intermediates in hydrocarbon combustion, yet are commercially unobtainable. Separate, high-pressure jet-stirred reactor experiments will be conducted on the group of cyclic ethers. Vacuum ultraviolet absorption spectroscopy and mass spectrometry detection schemes will produce quantitative, isomer-resolved measurements of species concentration. Effects of temperature, pressure, and oxygen concentration will be explored to probe regions of interest for next-generation combustion systems. The species measurements will serve as modeling targets for new combustion mechanisms produced in the project using a tandem approach combining Reaction Mechanism Generator and AutoMech codes. The results will identify connections between molecular structure and product formation from constitutional isomers and stereoisomers of cyclic ethers and their effects on the fidelity of combustion models. Such models show appreciable sensitivity to the narrow subset of reactions currently assigned to cyclic ethers. The influence of alkyl chain length in cyclic ethers on product formation and the influence of stereochemistry on product formation will be explored. 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. NSF Award ID: 2553997 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Brandon Rotavera | Institution: University of Georgia Research Foundation Inc, ATHENS, GA | Award Amount: $356,676 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2553997 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2553997.html