The Oxidation of Allene in a Low-Pressure H₂/ O₂/ Ar-C₃H₄Flame

We have studied the oxidation of allene in a rich ( φ = 1.5), low-pressure H2/O2/Ar flame to which one percent altene 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 + C2H3 (+ M) ↔ C3H4P H + C3H4P ↔CH3 + C2H2 H+CH3( + M) ↔ CH4( + M), where C3H4P is propyne. However, the main oxidation path appears to be C2H3 + H↔ C2H2 + H2 C3H2 + O2 ↔ products The underlying flame chemistry is discussed in depth, including the thermochemistry and molecular structure of various C3,H2 isomers.