Kinetic study of the thermal rearrangement of cis- and trans-2-pinanol

Pyrolysis of cis- and trans-2-pinanol is performed in a temperature range from 753 K to 843 K and conversions ranging from 10 to 96%. Kinetic models for the pyrolysis of both diastereomers are presented. Good agreement between simulated and experimental data was achieved in all cases. The reactivity and selectivity differences between the two reactant diastereomers can be attributed to a difference in activation energies of the carbon-carbon scission reaction that opens the cyclobutane ring of the reactant molecules and forms the 1,4-disubstituted cyclohexanol biradical: 206 kJ mol−1 in the case of cis-2-pinanol and 211 kJ mol−1 for trans-2-pinanol. The high selectivity for the linalool reaction channel compared to the parallel pathway to isolinalool was attributed to the large differences in activation energies, 19 kJ mol−1 for cis-2-pinanol and 14 kJ mol−1 for trans-2-pinanol, for the cyclobutane rupture reactions that form two types of biradicals, a 1,2-disubstituted and a 1,4-disubstituted cyclohexanol. All other kinetic parameters of the reactions in the kinetic models of cis- and trans-2-pinanol were not found to be significantly different for both diastereomers.