Towards the Development of Fiber-Based Oxidovanadium(IV) Catalysts for the Oxidation of Thioanisole

Abstract  

The catalytic activity of a series of bis-coordinated oxidovanadium(IV) complexes with 2-(4,5-diphenyl-1H-imidazol-2-yl)-4R-phenol ligands (R = NO₂, Br, H, MeO) was investigated for the oxidation of thioanisole by hydrogen peroxide in acetonitrile at 25°C. The substituent groups had a significant effect on the catalytic activity and followed the order NO₂ > Br > H > MeO, with the nitro (NO₂) derivative achieving >99% conversion after 10 min while the methoxy (MeO) derivative yielded the same result in 60 min. The nitro- and methoxy-substituted homogeneous catalysts were incorporated into polystyrene and electrospun to form nonwoven mats with fiber diameters in the range 0.33–1.98 μm. These vanadium incorporated fibers were subjected to a continuous flow system at a flow rate of 1 mL/h for the oxidation of thioanisole and the nitro-substituted catalyst showed excellent catalytic activity with conversions dropping from 99 to 93% in the 10th fraction while the drop was down to 88% for the methoxy-substituted catalyst.