Decomposition of Di-t-butyl Peroxide and Kinetics of the Gas Phase Reaction of t-butoxy Radicals in the Presence of Ethylenimine

Abstract

The reaction of di-t-butyl peroxide with ethylenimine has been studied between 129° and 154°C. The t-butoxy radicals formed by the rupture of the O–O bond of the peroxide, (CH3)3COOC(CH3)3→ lim k12(CH3)3CO,are postulated to enter into the following reactions: (CH3)3CO→ lim k2CH3COCH3+CH32CH3→ lim k3C2H6CH3+(CH2)2NH→ lim k4(CH2)2N+CH4(CH3)3CO+(CH2)2NH→ lim k5(CH2)2N+(CH3)3COH.The rate constant for the unimolecular decomposition of the peroxide into t-butoxy radicals is found to be in the range k1=6×1014e−36,000/RT to k1=6×1016e−40,000/RT sec−1. The activation energies E4—E3/2=4.8 kcal/mole and E2—E5=12 kcal/mole are calculated from the kinetic data. The complete rate expression for the capture of imine H atom by CH3 radical, k4=4.5×1010e−4800/RT (moles/cc)−1 sec−1,is obtained by using Gomer and Kistiakowsky's values for k3=4.5×1013 (moles/cc)−1 sec−1 and E3=0. The activation energy for the thermal decomposition of t-butoxy radical is about 17 kcal/mole if E4 and E5 of similar type H capture mechanisms are assumed equal.