KINETICS OF THE THERMAL GAS-PHASE DECOMPOSITION OF METHOXYCYCLOPROPANE

Article abstract of DOI:10.1039/f19837901413

In the temperature range 635-694 K, 70-80 percent of the methoxycyclopropane decomposing initially results in the formation of the isomerization products(E)- and (Z)-1-methoxyprop-1-ene and 3-methoxyprop-1-ene.THe residual decomposition results from approximately equal contributions from methyl-oxygen bond fission and the subsequent radical abstraction reactions.THe isomerization products are formed by homogeneous, non-radical, unimolecular pathways with high-pressure rate constants given by the equations k<(E)-+(Z)-1-methoxyprop-1-ene>/s^-1 = 10^13.29+/-0.75 exp(-226.5+/-9.5kJ mol^-1/RT) and k(3-methoxyprop-1-ene)/s^-1 = 10^14.0+/-1.1exp(-254+/-14 kJ mol^-1/RT).The methoxy group lowers the activation energy for opening the cyclopropane ring adjacent to the point of substitution by ca. 45 kJ mol^-1.