Time-resolved detection of a hydrocarbon pyrolysis intermediate with a diode laser

Summary form only given. The pyrolysis mechanism of the strained ring quadricyclane is complex and produces the soot precursors, acetylene cyclopentadiene and toluene. For heterosubstituted quadricyclanes with oxygen at the three position an oxepin intermediate is formed enroute to more stable products. The oxepin molecule has a broad uv absorption, which is accessible with a frequency-doubled visible laser diode at 340 nm. This represents a very uncommon situation wherein the pyrolysis of a hydrocarbon species produces an optically absorbing intermediate. This paper details the application of a diode-laser-based technique for real-time observation of the oxepin intermediate.