Oxidative Desulfurization of Gas Oil Catalyzed by (TBA)(4)PW11Fe@PbO as an Efficient and Recoverable Heterogeneous Phase-Transfer Nanocatalyst

摘要

In this paper, a tetra(n-butyl)ammonium salt of iron(III)-substituted phosphotungstate@lead oxide composite, (TBA)(4)P-W11Fe@PbO, was successfully synthesized by the thermal decomposition method as a nanocatalyst for oxidative desulfurization (ODS) of gas oil. The incorporation of the materials was confirmed by Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and P-31 nuclear magnetic resonance (NMR) characterization methods. To evaluate the catalytic activity of (TBA)(4)PW11Fe@PbO, the ODS process was carried out using a CH3COOH/H2O2 oxidizing agent at 60 degrees C. From the attained results, the total sulfur and mercaptan content of real gas oil were reduced with 97% efficiency after 2 h. Furthermore, the various comparative experiments were performed to investigate the capability of (TBA)(4)PW11Fe@PbO in ODS of prepared model fuel. Results were indicated that the kinetics of sulfur oxidation fitted the pseudo-first-order kinetic model. The probable mechanism was proposed via the electrophilic mechanism through the formation of a peroxometalate intermediate complex with phase transfer properties. After 5 oxidation runs, the heterogeneous nanocatalyst was separated and recovered easily.