(104c) Magnetic Nanoparticle Supported Metal Alkoxides for Ring-Opening Polymerization of Lactones

Polymerization catalysts are routinely single use catalysts, as neither the homogeneous (no easy recovery mechanism), nor the heterogeneous catalysts (polymer clogs catalyst pores and entraps the active sites) are easily recoverable and recyclable. Biodegradable poly(esters) that have wide applications in the biomedical and related industries can be produced by ring-opening polymerization (ROP) of cyclic lactone monomers. Although many highly active homogeneous metal complex catalysts have been reported as catalysts for the ROP of lactones, their application can be hampered by the difficulty and cost associated with recovering the metal residue. Heterogeneous catalysts (based on porous materials) for lactone polymerization can be easily recovered, however they usually cannot be reused due to pore clogging with polymer. We have identified magnetic nanoparticles (MNPs) as an ideal alternative support for recoverable polymerization catalysts due to their nonporosity, high external surface area, potential for facile surface modification, and easy recoverability under a magnetic field.

Here, MNP-supported metal alkoxides based on aluminium and yttrium are reported as a recoverable and recyclable catalysts for the ROP of ε-caprolactone. The preparation, characterization and catalytic performce of these new catalysts are reported. Recoverability and recyclability are also demonstrated.