Heterogeneous radical-generating catalysts based on cationic surfactants

Abstract

Proceeding from the earlier finding that cationic surfactants are capable of forming mixed micelles with amphiphilic hydroperoxides (LOOH) and catalyzing their decomposition to free radicals, heterogeneous catalysts for the radical degradation of LOOH have been prepared by depositing the cationic surfactant cetyltrimethylammonium bromide (CTAB) onto the solid supports montmorillonite (M1), microcrystalline cellulose (Cel1), and chitosan (Chi1). The performance of the obtained colloid catalysts in generating radicals in a hydroperoxide-containing medium decreases in the order Cel1 > Chi1 > M1 for the radical chain styrene polymerization process in the presence of cumyl hydroperoxide or row Cel1 > M1 > Chi1 in the case of limonene oxidation. The low activity of M1 in the initiation of polymerization is probably due to partial heterolytic decomposition of cumyl hydroperoxide on montmorillonite to give phenol.