The oxidation of allene in a low-pressure H-2/O-2/Ar-C3H4 flame

We have studied the oxidation of allene in a rich (phi = 1.5), low-pressure H-2/O-2/Ar flame to which one percent allene was added. Temperatures were measured by thermocouple and by OH laser-induced fluorescence. Stable species profiles were determined from mass spectrometer measurements using a quartz microprobe, and OH concentrations were determined using LIF. The experiments were analyzed with the aid of a chemical kinetic model. Significant quantities of methane and acetylene are formed early in the flame as a consequence of recombination of propargyl with hydrogen atoms, H + C3H3(+ M) <----> C3H4P H + C3H4P <----> CH3 + C2H2 H + CH3(+ M) <----> CH4(+ M), where C3H4P is propyne. However, the main oxidation path appears to be C3H3 + H <----> C3H2 + H-2 C3H2 + O-2 <----> products The underlying flame chemistry is discussed in depth, including the thermochemistry and molecular structure of various C3H2 isomers.