The authors studied soot formation during the pyrolysis of propane/Ar, propane/toluene/Ar, and rich propane/oxygen/Ar mixtures behind reflected shock waves. The time profiles of soot yield and temperature were obtained. The soot-suppressing effect of oxygen and soot-promoting effect of toluene were revealed. The results were simulated within the framework of a detailed kinetic model composed of 2760 direct and reverse elementary steps and involving 284 species. As compared to the authors' previous studies, the model was refined and tested against experimental data on pyrolysis and oxidation of a number of hydrocarbons. The measured and calculated time profiles of soot yield and soot particle temperatures, as well as soot yield temperature dependences, for the tested mixtures were found to be in close agreement.