Comparing the Catalytic Activity of Silica-Supported Vanadium Oxides and the Polymer Nanofiber-Supported Oxidovanadium(IV) Complex toward Oxidation of Refractory Organosulfur Compounds in Hydrotreated Diesel

Abstract

Silica-supported vanadium oxides (VxOy-silica 600 °C) and polymer nanofiber [2-(2′-hydroxy-5′-ethenylphenyl)imidazole (PIMv) and styrene (ST) copolymer]-supported oxidovanadium(IV) ([VIVO-p(PIMv-co-ST)]) were synthesized and used as catalysts for the oxidation of refractory organosulfur compounds in fuels in a continuous flow system. Conversion of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTO2) increased as the flow rate decreased, reaching 100% at flow rates of 0.1 and 0.2 mL/h for (VxOy-silica 600 °C) and [VIVO-p(PIMv-co-ST)], respectively. This was attributed to improved contact time between the catalyst and substrate, which allowed further oxidation to take place. However, the catalytic activity of VxOy-silica 600 °C dropped by 33% after the first oxidation cycle at a flow rate of 0.1 mL/h at 60 °C, unlike [VIVO-p(PIMv-co-ST)], which maintained its activity at 100% after three cycles. Optimized conditions were employed in the oxidation of a hydrotreated fuel sample (Sasol diesel 500) follow...