Oxidative Desulfurization of Aromatic Sulfur Compounds over Titanosilicates

Abstract

The application of several titanosilicates to the oxidation of aromatic sulfur compounds such as thiophene, benzothiophene, dibenzothiophene, and 4,6‐dimethyldibenzothiophene with H2O2 under mild conditions is reported. Superior to other titanosilicates, Ti‐MWW demonstrates a higher activity for the oxidation of 4,6‐dimethyldibenzothiophene owing to the unique pore structure of the MWW topology. The effects of solvent, temperature, catalyst amount, and H2O2/S ratio on the oxidation of 4,6‐dimethyldibenzothiophene over this catalyst are studied in detail. The catalyst is also applied to the oxidative desulfurization of commercial diesel. The sulfur compounds in the commercial diesel were oxidized to the corresponding sulfones, which could be readily extracted by acetonitrile, resulting in a maximum sulfur removal of 88 % .

On the key role of aluminium and other heteroatoms during interzeolite conversion synthesis

“…The hydrophobicity and the (Lewis-)acidic nature of the heteroatom containing zeotypes make these materials promising candidates in numerous redox catalysis reactions. [161][162][163][164][165][166][167][168][169][170] Alongside direct (in situ) synthesis, these materials can also be formed post-synthetically. [171][172][173][174] Typically this encompasses a two-step method involving chemical leaching and (heteroatom) impregnation.…”

“…199 [Sn]BEA has recently become a catalyst of great interest due to its Lewis acidic behaviour even in the presence of water, which has the potential for a variety of industrial applications. [161][162][163][164][165][166][167][168]200 However, traditional synthesis routes allow only a limited Sn content as the addition of Sn inhibits the nucleation of the [Sn]BEA zeolite and such routes are oen timeconsuming. 164,201 Substantial effort has been undertaken to optimise the synthesis of [Sn]BEA and maximise the Sn content.…”

SBA-15 Anchored Metal Containing Catalysts in the Oxidative Desulfurization Process

“…The reaction was performed in an nheptane/toluene mixture (8:2 wt %) at 80 °C under atmospheric pressure using an excess of cumene hydroperoxide (CHP) (CHP: Sulfur compounds 2:1) as its primary oxidant, to yield the corresponding sulfone derivatives (Figure 3). Mesoporous Ti-silica (pore size > 2 nm) showed higher catalytic activity and longer lifetimes than its microporous counterpart (pore size < 2 nm), such as titanium silicalite TS-1, thanks to larger access to the active site and the presence of coordinatively unsaturated tetrahedral titanium able to interact with the primary oxidant [82,83]. In accordance with these data, large cylindrical mesopores Ti-SBA-15 catalysts (pore size > 7 nm) have been prepared by post-grafting insertion of titanium alkoxide/acetylacetone (acac) chelates favoring the dispersion of tetrahedral Ti 4+ sites on the mesopore surface of the material, followed by the generation of hydrophobic surface sites by treatment with tetramethyldisilazane (TMDS) to avoid poisoning effects of the polar sulfoxide and sulfone products [84,85].…”

Efficient and reusable ordered mesoporous WOx/SnO2 catalyst for oxidative desulfurization of dibenzothiophene

“…4 Therefore, alternative processes have been suggested to overcome these drawbacks. So far, several alternative deep desulfurization technologies, such as adsorption, 5,6 extraction, 7,8 bioprocess, 9,10 oxidation, [11][12][13] and photocatalytic oxidation desulfurization 14,15 have been extensively investigated. Among these processes, oxidative desulfurization (ODS) combined with extraction process is considered to be one of the most promising processes.…”