Laboratory Investigations on the Formation of Aromatic Compounds in Titans Atmosphere Through Resonance Stabilized Radicals

Resonance stabilized radicals (RSRs) play a critical role in hydrocarbon reactions in combustion chemistry, planetary atmospheres, and the interstellar medium. RSRs possess conjugated -systems, leading them to be less reactive than other radicals. Propargyl radical (C3H3) recombination has been used to explain the formation of benzene, a crucial first step in Titans haze formation. However, these reactions have not yet been observed at the low temperatures relevant to Titans atmosphere. The possibility of nitrogen-containing heterocycles forming in Titans atmosphere would have significant implications for particle growth and prebiotic chemistry. Reactions of RSR species with reactive molecules such as isocyanides may be a viable pathway to the formation of heterocyclic compounds. Nevertheless, there is minimal investigation of these reactions. To bridge these knowledge gaps, propargyl radicals were produced through photolysis of propargyl bromide within a flow cell. This allows for the investigation of propargyl recombination and the reaction with reactive nitrogen-bearing molecules such as isopropyl isocyanide at and below room temperature. Product channels of the self-reaction of propargyl-radical, and cyano-radical reactions with propargyl radicals were analyzed through GC-FID. Product analysis of the radical reactions may provide evidence of the formation of C6H6 isomers and heterocyclic compounds in conditions relevant to Titans Atmosphere.