Desulfurization and Denitrogenation Processes to Treat Diesel Using Mo(VI)‐Bipyridine Catalysts

Abstract

High efficiency was found for desulfurization and denitrogenation processes to treat diesel using either the hybrid material {[MoO3(2,2′‐bipy)][MoO3(H2O)]}n or the octanuclear complex [Mo8O22(OH)4(di‐tBu‐bipy)4] (2,2′‐bipy = 2,2′‐bipyridine, di‐tBu‐bipy = 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine) as catalysts. These processes were employed in a single procedure to simultaneously remove sulfur (dibenzothiophene, 4‐methyldibenzothiophene, and 4,6‐dimethyldibenzothiophene) and nitrogen (indole and quinoline) compounds from diesel. A reaction time of two hours was sufficient to achieve at least 99.9 % S removal and 97 % N removal. Furthermore, the catalytic systems presented a high capacity to be reused/recycled for consecutive desulfurization/denitrogenation cycles.

Removing Simultaneously Sulfur and Nitrogen from Fuel under a Sustainable Oxidative Catalytic System

“…The difference in removal rates between IND and QUI relates to the higher basicity of the proton-donor present in IND [41,42]. During the oxidation catalytic step (after the 10 min), the difference of reactivity between the SCs can be explained by the decrease in electron density on the sulfur atom, which hinders oxidation [18]. The nature of the obtained oxidized products was identified by the analysis of the extraction phase, since, in the model diesel phase, no oxidized products were found.…”

“…Therefore, it is essential to remove NCs before the desulfurization treatment of fuel, or preferably, to remove NCs and SCs simultaneously by an alternative process, capable of depth desulfurization and denitrogenation, reducing the impact of fuels on the environment by decreasing NOx and SOx emissions. Oxidative desulfurization (ODS) and oxidative denitrogenation (ODN) processes have been the focus of promising research in recent years due to their efficiency for removal of the most refractory S and N-content present in fuels [10,17,18]. This technology conciliates oxidative catalysis and liquid-liquid extraction steps [15,16].…”

“…Hydrogen peroxide is generally the preferred oxidant to use in these processes due to its high active oxygen content and the fact that water is the sole by-product [23,24]. Our research group has been dedicated to the design of efficient catalysts for ODS based on polyoxometalates (POMs) [18,[25][26][27][28][29] POMs are polyanions incorporating various transition metals and are well-known by their structural diversity and potential in several areas of application [30]. In general, POMs are powerful catalysts for a great variety of oxidative reactions.…”

The Role of the Heterogeneous Catalyst to Produce Solketal from Biodiesel Waste: The Key to Achieve Efficiency

“…Fossil fuels are constituted by various sulfur and nitrogen constituents, that when burned, originate oxides (SOx and NOx), releasing harmful emissions (Figure 1). Furthermore, fossil fuels are also one of the main direct contributors of greenhouse gases (GHG), responsible for most carbon dioxide emissions [3,8]. As such, the European Union has planned to reduce 55% of GHG emissions by 2030, and completely eliminate them until 2050 [9].…”

Polyoxometalate-doped electrospun nanofiber mats as active catalysts for the production of clean fuels under solvent-free systems

“…4–6 Nevertheless, few reports deal with the combination of ODS and oxidative denitrogenation (ODN) in a single process capable of simultaneously removing both SCCs and NCCs. 13–19 Besides our research group, 18,19 other publications reporting the high efficiency of ODS and ODN use only single-component sulfur and nitrogen model oils; 16,17 processes require several hours of reaction; 13,14 or use t -BuOOH as an oxidant. 15 The majority of the reported processes use hydrogen peroxide as an oxidant, mainly due to the highly active oxygen content with water as the sole by-product.…”