Selective epoxidation of hydroxyl terminated polybutadiene using in situ generated dimethyl dioxirane in the presence of MoO3

Abstract

Hydroxyl terminated polybutadiene (HTPB) was epoxidized using in situ generated dimethyl dioxirane (DMD) as an oxidant and MoO 3 as a catalyst at 25 °C. Different reaction factors such as reaction time and catalyst concentration were examined. The ability of different C=C geometries toward epoxidation was evaluated in detail at various reaction times and the products were characterized by H NMR, 13 C NMR and FT-IR techniques and no side reaction were detected. It was found that hydroxyl group of the polymer chain was preserved in the oxidation reaction without using any conditional control and relative reactivity depended on chain microstructure in the following way: 1,4-cis > 1,4-trans > 1,2-vinyl. This method is easy, environmentally friendly, convenient and the reaction conditions are straightforward.