Modulated molecular beam mass spectrometric studies of the high temperature pyrolysis of hydrocarbons

The pyrolysis products of benzene and toluene were studied as functions of temperature (up to 2000/sup 0/C) and pressure. Above 1400/sup 0/C, most of the larger species are unstable; above 1700/sup 0/C, no species heavier than C/sub 6/H/sub 6/ are observed at any pressure. Above 1500/sup 0/C and at higher pressures, the products are dominated by species containing even numbers of carbon atoms (C/sub 2/ to C/sub 12/). While polyacetylenes up to C/sub 8/H/sub 2/ were observed, they are present in low abundances, with the max concentrations occurring at 1350/sup 0/C. Polycyclic aromatic hydrocarbons are formed readily. 6 figures. (DLC