Penicillium expansum lipase-coated magnetic Fe3O4–polymer hybrid hollow nanoparticles: a highly recoverable and magnetically separable catalyst for the synthesis of 1,3-dibutylurea

Herein, amino-epoxy supports were innovatively imported onto magnetic nanoparticles (Fe3O4–polymer hybrid nanospheres) for immobilizing enzymes. This new support has a coating layer with dual functional groups (epoxy and amino-epoxy). Consequently, this support has great anionic exchange power and a high number of epoxy groups. The acquired immobilized Penicillium expansum lipase in combination with this heterofunctional support represents a novel class of heterogeneous catalyst towards the synthesis of 1,3-dibutylurea from ethylene carbonate and butylamine, which has not been very commonly catalyzed by enzymes. After optimization of the reaction conditions, the yield of 1,3-dibutylurea was 77% under solvent free conditions at 60 °C. Moreover, after completion of reaction, the catalyst was simply recovered by an external conventional magnet and recycled without significant loss in the catalytic activity (up to ten cycles).