Chemoselective epoxidation of hydroxyl-terminated polybutadiene (HTPB) using in-situ generated dimethyl dioxirane (DMD)

摘要

In this report hydroxyl-terminated polybutadiene (HTPB) was functionalized to epoxi-dized HTPBs containing various epoxide group moieties by using in situ-generated dimethyl dioxirane (DMD) as oxidant and tetra-n-butyl ammonium bromide as a phase-transfer catalyst (PTC) in convenient,simple and mild conditions.The system shows to be sensetive to electronic,steric and chain microstracture factors and reveals the high reactivity of cis in comparison with trans and vinyl double bonds.1H-NMR,13C-NMR and FT-IR spectra analysis of the products reveal that no significant side reactions take place in this system even at high epoxidation levels.Influences of various factors,i.e.,reaction time and the PTC concentration were investigated in detail.Also,it was found that double bonds oxidized chemoselectively in comparision with terminal hydroxyl groups.