Kinetics of the pyrolysis of n-butane

Abstract

The thermal decomposition of n-butane was investigated at temperatures ranging from 330 to 420 °C. This extension of the temperature range for such studies was made possible by the use of a highly sensitive analytical system, consisting of a gas–liquid chromatograph equipped with a hydrogen-flame-ionization detector which permitted the determination of the major products of the reaction at reactant conversions as low as 0.0002%. At temperatures below 400 °C the reaction order was both temperature and pressure dependent, a lower order, approaching 0.5, being favored at lower temperatures and higher pressures. The contribution to the reaction mechanism of a chain-termination step consisting of the combination of 2 secondary butyl radicals explains the observed phenomena.