Aromatization of a C4 alkane/alkene/hydrogen mixture obtained by catalytic dehydrogenation of isobutane

The aim was to establish whether there is competition between the dehydrogenation of an alkane to an alkene and its aromatization in the presence of hydrogen. The aromatization of the model compound isobutane was studied in two steps, firstly its catalytic dehydrogenation and secondly the direct thermal cracking of the dehydrogenation mixture at atmospheric pressure and at temperatures at which substantial aromatization of alkenes occurs. The role of hydrogen was studied by cracking mixtures of known composition. In all instances, the yields in aromatic hydrocarbons, although lower than expected, were higher than those obtained with the alkane. The inhibitory effect of hydrogen on aromatization was demonstrated.