Recoverable and Recyclable Catalysts for Multi-Step Reaction Networks

摘要

Amine functionalized superparamagnetic cobalt spinel ferrite nanoparticles have been synthesized and evaluated in one-pot, acid/base catalyzed cascade reactions. When combined with traditional, nonmagnetic catalysts, use of these nanoparticles facilitated the straightforward recovery of multiple, different catalysts from one-pot, multi-step reactions. Sulfonic acid functionalized Amberlyst polymer resins catalyzed the deacetalization of benzaldehyde dimethylacetal to benzaldehyde. The amine functionalized nanoparticles then catalyzed the Knoevenagel reaction of benzaldehyde with malononitrile. Post-reaction, the acidic resin and basic nanoparticle catalysts were separated magnetically and recovered in pure form. Kinetics of initial and recycle reactions indicate no catalyst deactivation. This research illustrates the first example of recovering pure catalysts from one-pot, multi-step reactions, made possible by utilizing the superparamagnetic character of the CoFe_2O_4 nanoparticles.