Guided-ion Beam Tandem Mass Spectrometry Research Articles

Pyrolysis and Isomerization of Quadricyclane, Norbornadiene, and Toluene

Pyrolysis and isomerization of the C7H8 isomers quadricyclane, norbornadiene, cycloheptatriene, and toluene have been studied in a micro-flow tube reactor with detection/isomer identification by guided-ion beam tandem mass spectrometry. The methodology permits pyrolysis studies with product isomer identification with samples of only a few milligrams. The samples are premixed with buffer gas and then passed through a temperature-controlled flow tube reactor with millisecond residence time. The sample/pyrolysis products exiting the flow tube are ionized by methane chemical ionization (CI), and both CI mass spectra and low-energy collision-induced dissociation were used to determine the composition. For the experimental residence time, toluene and cycloheptatriene are stable over the 298−998 K temperature range. Decomposition of norbornadiene sets in at ∼600 K. The dominant decomposition processes are acetylene elimination via a retro-Diels−Alder reaction and isomerization to toluene. Quadricyclane begins to...