Novel high TEMPO loading magneto-polymeric nanohybrids: An efficient and recyclable Pickering interfacial catalyst

We report herein the design and preparation of novel magneto-polymeric nanohybrids that can be used as efficient and recyclable Pickering interfacial catalyst (PIC) in selective oxidation of alcohols. The nanohybrids Fe 3 O 4 @SiO 2 @PTMA, bearing catalytic TEMPO functionalities, were synthesized through distillation-precipitation polymerization (DPP) of the precursor monomer 2,2,6,6-tetramethyl-4-piperidyl methacrylate (TMPM) and subsequent oxidation reaction. TEM, FT-IR, DLS, EA confirmed and quantified the TEMPO loading of nanohydrids (1.0–2.4   mmol   ·   g −1 ). It was found that the TEMPO loading, particle size, as well as surface hydrophilicity could be finely tuned via simply adjusting the TMPM monomer fraction during polymerization. The performance of the resultant nanohybrids as PIC was then evaluated in a typical Anelli system, which showed superior catalytic activity for selective oxidation of alcohols. Moreover, the PIC can be easily recycled by applying magnetic field, and reused for the following cycles of oxidation without any loss on either conversion or selectivity.