Kinetics and mechanism of the gas-phase thermal decomposition of cis-2-methylcyclopropane methanol

The kinetics of the gas-phase thermal decomposition of cis-2-methylcyclopropane methanol was studied in the temperature range of 483–597 K and pressures between 5–24 Torr in aged Pyrex reactions vessels. Cis-2-methylcyclopropane methanol underwent first order, reversible geometric isomerization in competition with structural isomerization. The structural isomerization products were identified as 2-peten-1-ol and a mixture of cis and trans-2-methyl-buten-1-ol. Arrhenius parameters were determined for homogeneous, unimolecular formation of the isomeric products and for the overall loss of reaction. The formation of isomeric products and the observed Arrhenius parameters are consistent with a biradical mechanism. For the overall reaction, Ea = 173.8 ± 15.5 (kJ/mol) and log10 (A, s−1) = 13.3 ± 1.5. These values are in good agreement with previously reported values for similar studies of 1,2, disubstituted cyclopropanes.