47285-G6
Characterization of Combustion Product Pathways Using Chirped-pulse Broadband Microwave Spectroscopy
Characterization of Combustion Reaction Pathways Using Chirped-Pulse Broadband Microwave Spectroscopy There is currently one graduate student working on this project. Over the course of the past year we have designed and built a high-voltage electric discharge, pulsed nozzle. The electrodes and several of the electrical components were designed by students and the Amy Facility at Purdue University. The design, construction, and purchasing of major components was completed in approximately three months after the award of the grant. The preliminary work was looking at the unimolecular dissociation of 2,3-dihydrofuran (DHF). The molecule was dissociated in a potential field of 1000 V through Penning Ionization in Argon then expanded into a vacuum creating a super-sonic expansion. The expansion serves to quench the chemical reaction and cool product species to a few degrees Kelvin. The product species were then probed with an ultra-broadband microwave radiation and their rotational spectra were recorded. We have characterized up to 14 distinct species in the product spectrum. These include formaldehyde, propyne and propene as lighter fragment species. More interestingly, we have identified several isomeric and conformational species of the starting product DHF. These include cis- and trans-cyclopropane carboxaldehyde (CPCA) and trans-crotonaldehyde (CA). No evidence of the cis form of CA was observed in the spectrum. We are currently writing up these results for publication as a communication. Future work on this project will focus on two areas: Unimolecular dissociation, and bimolecular reactions. We are currently studying 2,5-DHF as a comparison to the 2,3-DHF results. The preliminary results are quite different from 2,3-DHF in the dominant species detected in the discharge spectrum is propyne. Our plans for bimolecular reaction will begin with studying small hydrocarbons such as butadiene and benzene with O2. Our interest is in more accurately simulating a combustion environment i.e. an oxygenated atmosphere. We plan on beginning this work later this fall.
