The thermal isomerization and dehydrogenation of cis-3a,7a-dihydroindene

Abstract

In the gas phase, in the temperature range 358–399 °C, cis-3a,7a-dihydroindene undergoes two simultaneous reactions which are both homogeneous and kinetically of the first order. The major pathway is an isomerization to allylbenzene. The Arrhenius equation for this reaction is k₁= 10^{14·19 ± 0·09} exp (–219,900 ± 1100 J mole^–1/RT) sec.^–1. The minor pathway which leads to the formation of indene and hydrogen yields rate constants which fit the Arrhenius equation k₂= 10^{12·77 ± 0·16} exp (–208,900 ± 2000 J mole^–1/RT) sec.^–1. These results are discussed and tentative conclusions drawn about the transition states involved in the reactions.