Electrooxidation of Alcohols in a Disperse System with N-Oxyl-immobilized Polyethylene Particles as Disperse Phase and Aqueous NaHCO₃/NaBr as Disperse Media: A Totally Closed Electrolysis System

Abstract

Electrooxidation of alcohols was performed successfully in a disperse system with N-oxyl immobilized polyethylene particles as disperse phase and an aqueous saturated NaHCO₃ solution involving 20 wt% NaBr as disperse media. The N-oxyl immobilized polyethylene particles were prepared by heating a suspension of polyethylene particles (3 × 3 × 0.02 mm³) in fuming nitric acid at 80 °C for 1 h followed by treatment with 4-amino-2,2,6,6-tetramethylpyperidine-1-oxyl in chlorobenzene in the presence of DCC. Recycle use of the N-oxyl-immobilized polyethylene particles and the aqueous media was performed successfully without significant change of the yields of the products and current efficiency, thereby offering a totally closed electrolysis system.

electrooxidation - alcohol - N-oxyl - polyethylene particles - aqueous disperse media - disperse system

References

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IR spectra of the polymer particles showed a characteristic absorption band at 1712 cm^-1 due to carboxylic acid, which disappeared during the subsequent treatment with 4-amino-2,2,6,6-tetramethylpiperidine-N-oxyl.

7

Carried out on a Yanaco GC 6800 with a Quadrex Corporation fused silica glass capillary column (methyl phenyl 5: 25 m × 0.25 mm i.d.). Column 100 ºC, injector 270 ºC, detector 300 ºC, carrier gas, He; flow rate, 26 mL/min.

8

Electrogenerated iodine species, e. g., I₂ and IO^-, would not act as the oxidant for generation of N-oxoammonium ion from N-oxyl.