Recent Advances in Catalytic Oxidation of Organic Sulfides: Applications of Metal–Ionic Liquid Catalytic Systems

Abstract

Catalytic oxidation of organic sulfides is of considerable significance in industrial chemistry and fuel industry. Therefore, numerous methods have been developed for the oxidation. Metal-containing ionic liquid-based catalysts can catalyze the selective oxidation reactions and are highly used in chemical processes, which have also been used as effective solvents, reaction media, extractants, and catalysts for the oxidation of organic sulfides including oxidative desulfurization of fuel oil. Recently, much attention is being drawn to the preparation of heterogenous catalysts based on the immobilization of metal- or nonmetal-containing ILs on diverse solid supports, which can be easily separated after the completion reaction and recycled. Therefore, there is still an increasing interest in developing new and efficient catalytic procedures for the oxidation of organic sulfides. In this review, we have outlined the recent advances in catalytic oxidation of organic sulfides including oxidative desulfurization of fuel oil. The versatilities and adaptabilities of metal–ionic liquid catalytic systems in the selective oxidation of sulfides are considered a powerful research field in these transformations.

Ionic Liquids in Metal, Photo-, Electro-, and (Bio) Catalysis

“…Second, in the majority of the reports, the IL "catalytic" phase is used in over-stoichiometric amounts relative to the amount of S-compounds in the model oil. Third, the use of air/oxygen, a greener and more sustainable oxidant, for these oxidations has been rarely reported 1512,1513,1521 The highly dispersed Nb oxoclusters can absorb a large amount of polar organic solvents and thus were swollen greatly, which exhibited "pseudo" liquid phase behavior and enabled the substrate molecules to be highly accessible to the catalytic center of the Nb oxocluster units. 1523 In this case the IL-catalyst behaves as a micelle-like system by increasing the concentration of both reagents in the catalytic active phase.…”

“…1511 The use of ILs in these processes has been the object of a comprehensive review in 2017 1512 and a specialized one on organic sulfides in 2021. 1513 In this section we will focus on discussion of the effects of the ILs in epoxidations and dihydroxylations and present mainly the results published in the last 6 years.…”

“…An alternative approach that is highly employed for ODS is the SILP-type catalysts. 1513 Indeed, SILP catalysts are emerging as a potential alternative for ultradeep desulfurization in view of their inherent advantages as compared to the classical solvent IL approach (Table 23).…”

“…ILs containing metal anions have been used for various processes such as oxidation of S -containing compounds, alcohols, halides, alkanes, and arenes and epoxidations (Scheme ). The use of ILs in these processes has been the object of a comprehensive review in 2017 and a specialized one on organic sulfides in 2021 . In this section we will focus on discussion of the effects of the ILs in epoxidations and dihydroxylations and present mainly the results published in the last 6 years.…”

Increasing Complexity in Adamantyl Thioethers Characterized by Rotational Spectroscopy

“…[4] In drug design, the thioether group (RÀ SÀ R') is of special importance; thioethers can be found both in linear and cyclic moieties of bioactive molecules. [5,6] Additionally, thioethers are common starting points in the formation of higher oxidation state sulfur derivatives, both synthetically [7] and in nature. [8] Other molecular scaffolds that impart unique properties based on their distinctive structure are diamondoids.…”