Shock tube studies of the high temperature pyrolysis of acetylene and ethylene

Abstract

Shock heating of acetylene and ethylene, under the conditions 1500–2500 K, 1–2 bar and molar fraction 0.07–2 % hydrocarbon in argon, has produced spectrographic evidence concerning the products of pyrolysis. Kinetic spectrophotometry was used in the wavelength range 250 nm-1.5 µm. The variation of the absorption spectra with temperature, hydrocarbon pressure and time were investigated, and suggest that polyacetylenes were formed. Simple kinetic analysis has given rate constants for the formation of polyacetylenes and the polyacetylene concentration was found to reach an equilibrium value within the observation time in some cases.