An effort to generalize the thermal isomerization of 6,6-dimethylbicyclo[3.1.1]heptanes and 6,6-dimethylbicyclo[3.1.1]heptenes: Comparative pyrolysis of pinane, α-pinene, and β-pinene

This article, based on a presentation at the 18th International Symposium on Analytical and Applied Pyrolysis in Costa Teguise, May 18–23, 2008, will give a brieve approach for systematization of thermal rearrangements occurring within the series of pinane- and pinene-type compounds. To reach this goal, gas-phase pyrolysis experiments with the most abundant pinane- and pinene-type monoterpenes (cis-pinane, trans-pinane, α-pinene, and β-pinene) were performed in a flow-type apparatus using nitrogen as carrier gas. Performance of kinetic experiments under similar reaction conditions allows for the comparison of the activation parameters calculated from Arrhenius and Eyring theory. Thus it was possible to gain a deeper insight into the reaction mechanisms and the reaction intermediates the reactions pass through. Results are compressed in five general rules allowing for description of the pyrolysis processes of compounds in the bicyclo[3.1.1]heptane- and bicyclo[3.1.1]heptene-series.