Influence of the Nature of Crosslinking Agent on the Oxidation Behavior of Crosslinked Polystyrene‐Supported Polyoxyethylene Bound Permanganate

Abstract

Polystyrene‐supported polyoxyethylene (PSPOE) bound permanganate with varying crosslinking agents have been prepared and used as a new class of recyclable oxidizing agents for low molecular weight alcohols and aldehydes. The effect of the nature of crosslinking agents on the oxidation reactions was studied in detail. The crosslinking agents used were ethyleneglycol dimethacrylate (EGDMA), 1,4‐butanediol dimethacrylate (BDDMA), and 1,6‐hexanediol diacrylate (HDODA). Polymer supports were synthesized by free radical suspension polymerization. Chloromethylation was done using the Friedel‐Crafts reaction. A cyclic polyether type compound was developed by the reaction of functionlized resin with polyethylene glycol (PEG600) and sodium. Polystyrene‐supported polyoxyethylene was equilibrated with potassium permanganate in benzene to give the oxidizing agent. The results reveal that the reactivity of HDODA‐crosslinked system shows higher reactivity than the BDDMA, and EGDMA‐crosslinked systems. This is due to higher flexibility of the HDODA‐crosslinked system compared to the BDDMA, and EGDMA‐crosslinked systems. The effect of solvent, temperature, and molar concentration of the reagent on oxidation were carried out using benzoin to benzil as the model reaction. For a less flexibile EGDMA‐crosslinked resin, tetrahydrofuran (THF) is the best solvent, for BDDMA‐crosslinked system dioxane and for the highly flexible HDODA‐crosslinked system CHCl3 is found to be best. In all cases, the reactivity of the reagent increased with an increase in temperature and molar excess of the reagent.