Polyethylene‐supported N‐bromosuccinimide polymeric reagent for use in some oxidation reactions

Abstract

AbstractWe report a three‐step preparation of a polymer‐supported oxidizing reagent, polyethylene‐g‐N‐bromosuccinimide (PE‐g‐NBS), through the graft copolymerization of maleic anhydride (MAn) onto polyethylene (PE) by a photochemical method with 1% benzophenone as a photosensitizer. The postgrafting treatment of polyethylene‐g‐maleic anhydride (PE‐g‐MAn) with urea on fusion gives polyethylene‐g‐succinimide (PE‐g‐succinimide), which, on further treatment with an aqueous solution of sodium hydroxide and bromine, gives the required reagent, PE‐g‐NBS. The maximum percentage grafting (25%) was obtained with 3.57 mol of MAn and 0.5 mL of 1% benzophenone in 120 min. Fourier transform infrared spectroscopy and thermogravimetric analysis methods were used to characterize the graft copolymer PE‐g‐MAn, PE‐g‐succinimide, and the polymeric support, that is, PE‐g‐NBS. The grafted PE and the polymeric support were found to be thermally stable. The polymer‐supported N‐bromosuccinimide was used successfully for the efficient oxidation of a series of alcohols, including 2‐propanol, n‐butanol, ethylene glycol, cyclohexanol, poly(vinyl alcohol), benzoin, benzyl alcohol, and chloromycetin, to their corresponding aldehydes and ketones. The selectivity of PE‐g‐NBS toward the oxidation of secondary alcoholic groups without the disturbance of the primary alcoholic groups was reflected during the oxidation of chloromycetin. The oxidized products were characterized by Fourier transform infrared and 1H‐NMR spectral methods. The reagent was reused for the oxidation of fresh alcohols, and it was found to oxidize them successfully, although with a little lower product yield. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011