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Catalytic oxidative desulfurization (ODS) is emerging as a potential alternative to deep hydroprocessing as a result of its milder operating conditions and no hydrogen requirements. In this study, ODS catalysts based on a mesoporous TUD-1 support were developed to overcome the diffusion limitation of zeolite-based catalysts in oxidizing large-size organosulfur compounds present in real petroleum feedstocks. Different mesoporous oxidation catalysts were formed by substituting Ti in the TUD-1 framework and impregnating Keggin molybdenum heteropolyacid (HPA) on the TUD-1 support. The mesoporosity of TUD-1 and the presence of Ti(IV) and Mo Keggin units in the prepared catalysts were confirmed from the characterization results of X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption near edge structure, and Brunauer−Emmett−Teller N 2 surface area analyses. The ODS performance of catalysts was studied using a mild hydrotreated bitumen-derived heavy gas oil feedstock. The HPA-dispersed Ti−TUD-1 catalyst was found to be most active for desulfurizing the heavy gas oil feedstock as a result of a strong synergy effect of Ti and Mo Keggin ions on catalyzing oxygen transfer from an oxidant to a substrate. Oxidants, such as hydrogen peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, and molecular oxygen, were screened in this study. The first two oxidants were better than others and equally efficient. The HPA/Ti−TUD-1 catalyst was found to be suitable for ODS and oxidative denitrogenation (ODN) in both the batch stirred-tank reactor and continuous fixed-bed reactor systems.

A continuous gas flow magic angle spinning (MAS) NMR probehead has been developed, which enables simultaneously the observation of catalytic events occurring on catalyst surfaces and the on-line identification of the gas products in the output using mass spectrometry. The temperature inside the MAS rotor in the probe has been controlled and measured by 207 Pb MAS NMR spectroscopy of Pb(NO 3 ) 2 . The hydrogenation of toluene to methylcyclohexane on Pt/ZrO 2 -SO 4 (sulfated zirconia) has been used to demonstrate the ability of this probe to study heterogeneous reaction in situ in flow conditions (operando). The MAS NMR and mass spectrometry were in good qualitative agreement for the analysis of the reaction products. The reaction performed in parallel under similar conditions on a conventional fixed bed catalytic reactor shows that the reactant diffusion and their interaction with the active sites in the MAS NMR reactor are comparable in both conventional and NMR experiments. To cite this article: V.