Mesoporous Zeolite as a New Catalyst for Polymerization of Lactones

Polymerization of lactones such as δ-valerolactone (VL) and ε-caprolactone (CL) with protic compounds proceeded in the presence of an aluminosilicate mesoporous zeolite Al-MCM-41 (pore diameter of 27 Å, surface area = 1,010 m2 g−1), to give polyesters with narrow molecular weight distribution. The polymerization is likely to proceed via the activated monomer mechanism by the cooperative function of Lewis acidic aluminum and Brønsted acidic silanol functionalities on the interior wall. With titanate-mounted MCM-41 (Ti-MCM-41), the polymerization of VL gave a polymer containing an extremely high molecular weight fraction.