Kinetic measurements by H-1 NMR spectroscopy and chemically induced dynamic
nuclear polarization (CIDNP) effects were used to study thermolysis of sol
utions of acetyl propionyl peroxide in methanol-d(4). It is found that the
thermolysis may occur both by radical and by nonradical mechanisms. A schem
e of the thermolysis is proposed. Parameters of the Arrhenius equation for
the rate constants of the decomposition of the peroxide and the decarboxyla
tion of acyloxyl radicals are obtained.