Soot formation in pyridine and toluene pyridine mixtures diluted in ar
gon was studied behind reflected shock waves using a laser beam attenu
ation technique, over the temperature range 1520-2495 K and pressure r
ange 175-359 kPa. Pyridine on pyrolysis gave soot in a similar fashion
to aliphatic rather than aromatic hydrocarbons, whereas it gave soot
as much as did toluene alone when it was added to toluene. A shift in
the bell-shaped soot yield-temperature plot to lower temperatures was
also observed when pyridine was added to toluene. The difference in so
ot yield between toluene and pyridine pyrolysis emphasizes the importa
nce of the first ring as well as that of the products after thermal de
composition of the parent fuel.