Nitroxide polymer brushes as efficient and recoverable catalysts for the selective oxidation of primary alcohols to aldehydes

Abstract

ABSTRACT2,2,6,6‐Tetramethylpiperidinyloxyl (TEMPO)‐containing polymer brushes were grafted onto crosslinked polystyrene microspheres via surface‐initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) of 2,2,6,6‐tetramethyl‐4‐piperidyl methacrylate, followed by an oxidation process with 3‐chloroperoxybenzoic acid as oxidant. The synthesized nitroxide polymer brushes included homopolymer brushes, block copolymer brushes, and random copolymer brushes with various TEMPO contents and molecular weights. They were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, nuclear magnetic resonance spectroscopy, and gel permeation chromatography. These nitroxide brushes bearing high TEMPO contents were used as recoverable catalysts for the hypochlorite and aerobic oxidation of primary alcohols to aldehydes. The effects of polymer brush structure on the catalytic properties were studied and discussed. The results showed that these nitroxide polymer brushes had excellent catalytic properties and good recycling performances. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44365.