Heterogeneous catalysis for ring opening anionic oligomerisation

New heterogeneous catalysts for ring opening oligomerization are obtained by grafting alkyl aluminium moieties on silica. Adding alcohol in excess causes the formation of aluminium alkoxides and allows the catalytic mode, because of a rapid exchange reaction between the grafted active centers and the free alcohols present in the medium. All the polymer chains are end-capped by these alcohol molecules, which give functionalized oligomers.