Polystyrene beads supported phosphazene superbase as recyclable organocatalyst for ring-opening polymerization of δ-valerolactone.

The eco-environmentally PVLs without catalyst-residue have been facilely synthesized using heterogeneous PS- t -BuP 2 catalyst by simple filtration and without tedious purification process. • The heterogeneous catalyst PS- t -BuP 2 was employed for ROP of δ -VL. • PS- t -BuP 2 is easily recovered and reusable for five cycles without deactivation. • PVLs without catalyst-residue are synthesized using PS- t -BuP 2 by simple filtration. We demonstrated that the dimeric 1- tert -butyl-2,2,4,4,4-pentakis(dimethylamino)-2Λ5, 4Λ5-catenadi(phosphazene) supported on polystyrene (PS- t -BuP 2 ) was an efficient and recyclable catalyst for the ring-opening polymerization (ROP) of δ -valerolactone (δ -VL). The heterogeneous catalyst PS- t -BuP 2 could be recycled and reused for five consecutive cycles without significant decrease of catalytic activity. The monomer conversions maintained between 79% and 85% for five cycles. Using BnOH as initiator, the produced polyvalerolactones (PVLs) had controlled molecular weights (MWs) and narrow MW distributions (Đ), and the products were free of catalyst by simple filtration. The 1H NMR and MALDI-TOF characterizations of the obtained PVLs clearly indicated the presence of the initiator residue at the chain end. [ABSTRACT FROM AUTHOR]