Effect of ionic liquid on the thermal decomposition of cyclic organic peroxides

The thermolysis of cyclic diethylketone triperoxide (3,3,6,6,9,9-hexaethyl-1,2,4,5,7,8-hex aoxacyclononane, DEKTP) and cyclic pinacolone diperoxide (3,6-diterbutyl-3,6-dimethyl-1,2,4,5-tetraoxacyclohexane, PDP) was studied in neat N,N-dimethylformamide (DMF) and in binary mixtures DMF/Ionic Liquid (1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM+][BF4-]). The activation parameters for the decomposition of both peroxides in DMF, correspond to a process of homolytic cleavage of one O-O bond, generating a biradical in the initial step of radical mechanism. The rate constant values (k(d)) are higher for reactions performed in mixtures. A gradual increase of [BMIM+][BF4-] in the reaction media generates higher kd for both peroxides (i.e. k(d), DEKTP in DMF/[BMIM+][BF4-] 4.0 mol L-1 is 3.3 times greater than the kd obtained for the mixture with a concentration 1.0 mol L-1, under the same experimental conditions). The increase in decomposition rate can be associated with a more solvated and stabilized transition state when the ionic liquid is part of the reaction medium. (C) 2016 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.