A Deep Analytical Study in the Oxidation Polymerization Desulfurization Process Using a Keggin-Type Polyoxometalate Catalyst: Characterization of Solid and Liquid Products

Abstract

In this study, oxidation of a model fuel, benzothiophene (BT) in n-decane, using polyoxometalate catalyst with Keggin structure has been investigated. The solid product evaluation was performed using gel permeation chromatography (GPC), thermal gravimetric analysis (TGA)/(DSC) differential scanning calorimeter, FTIR, proton and carbon nuclear magnetic resonance (¹H + ¹³C NMR) spectrums, elementary (C, H, N and S) analyses. The results showed that the solid product was a polymer with a weighted average molecular weight (Mw) of 183030. In addition, the polymer was found to be sticky, branched and cross-linked. Moreover, for the first time, the role of the different solvents in the formation of the polymer was studied. It was revealed that the solvent intermolecular force plays an important role in polymerization so that the solvent with stronger molecular force did not participant in the polymerization. Ultimately gas chromatography-flame ionization detector (GC-FID) analysis showed the amount of desulfurization was about 81%.