Pyrolysis of Propyne/2-Methylbut-1-ene-3-yne mixtures between 350 and 450°C

2-Methylbut-1-ene-3-yne and Propyne mixtures were pyrolyzed at 350–450°C in the absence and presence of O₂ and NO. The major product of the reaction is a polymer, but m-xylene and p-xylene are also produced and were studied as the species of interest. The C₈H₁₀ formation rate is first-order in C₃H₄ and C₅H₆. The rate coefficient is best fitted by though it is not inconsistent with where R is the ideal gas constant in kJ/mol-K. Experiments in the presence of NO show that m-xylene and p-xylene formation occur by two processes: a concerted molecular mechanism (? 41%) and a singlet diradical mechanism (? 59%).