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ABSTRACT 2‐Thioxo‐4‐thiazolidinone which is trivially known as rhodanine is a five‐membered heterocycle, containing a sulfur and nitrogen atom at 1 and 3 positions, respectively. It is a very attractive class of compounds, because derivatization of rhodanine yields a number of molecules having multifarious application in medicinal chemistry and biology. There are many molecules derived from rhodanine which are already being used commercially as drug molecules. So owing to the importance of rhodanine in the field of medicinal chemistry and biology, a comprehensive review familiarizing different derivatives of the parent molecule rhodanine and their syntheses is highly warranted. In this review, we have broadly categorized the reactions of rhodanine as; (a) Knoevenagel condensation through the C‐5 active methylene group with carbonyl compounds, (b) nucleophilic attack on thioxo group at position 2 of rhodanine by aliphatic amines, (c) thioxo to oxo conversion, and (d) all other reactions. So far, to the best of our knowledge, no such literature which accounts for all the different kinds of reactions of rhodanine is reported. Here, we have not only presented the reactions schemes from various literatures, but we have discussed about the advantages and inadequacies of that particular catalytic processes. Moreover, at the end of this article we have given our own critical analysis on these literature reports, based on our understanding and experience. [ABSTRACT FROM AUTHOR]

Desulfurization is a significant approach to producing clean fuel. The design of novel host–guest catalysts with multiple active sites at atomic‐ and nano‐scales, opens a new door to gain an ultrahigh synergistic performance for targeted applications. Herein, an in situ solvent‐free approach is conducted for synchronously implanting Pd single sites (PdSS) and nanoparticles (PdNP) into a novel Zr‐based metal–organic framework (Zr‐MOF). The optimal catalyst exhibits ultrahigh oxidative desulfurization (ODS) performance that can oxidize 1 000 ppm sulfur with diluted oxidant at 40 °C within 5 min. The turnover frequency of the catalyst at 40 °C reaches 774.7 h−1 which is 47.4 times higher than host Zr‐MOF and surpasses the most reported ODS catalysts. A substantial synergistic effect between PdSS and PdNP is responsible for the upgradation of ODS performance. Experimental and theoretical results indicate that PdSS in Zr‐MOF can readily absorb H2O2, and synergistically decompose H2O2 with the assistance of PdNP for accelerated generation of •OH radicals that dominates the ODS performance. This work provides a new solvent‐free way for in situ implanting synergistic catalytic sites into MOFs to upgrade their catalytic performance in targeted reactions. [ABSTRACT FROM AUTHOR]

A series of catalysts, X%PMoV (X=10, 20, 30, 40, 50), were prepared through loading X% (mass fraction of SBA-15) Keggin-type H4PMo11VO40 (PMoV) on mesoporous SBA-15 by incipient-wetness impregnation method, which were utilized as visible-light catalysts for photothermal oxidation desulfurization at room temperature. The catalysts were characterized by brunauer Emmett Trller (BET), fourier transform infrared spectroscopy (FT-IR), powder X-ray diffration (PXRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis. X%PMoV catalysts showed photothermal conversion ability in acetonitrile solvent, and the photothermal conversion efficiency increased with the increase of PMoV. The oxidation desulfurization experiment of dibenzothiophene (DBT, as an example) was carried out in model oil with oxidant H2O2. The results show that the catalyst has the synergistic oxidative desulfurization ability of photocatalysis and photo-driven thermal catalysis on DBT. Due to the effective load of the active PMoV in the SBA-15 channels, the catalyst has good cyclic stability and substrate oxidation product selectivity when the load is 30%. The photothermal catalytic desulfurization strategy is also applicable for other thiophene derivatives and thioether compounds. This paper provides a new idea for using visible-light absorption active components loaded on zeolite for photocatalytic and thermocatalytic desulfurization applications. [ABSTRACT FROM AUTHOR]

Heterogeneous interfaces designed rationally in catalysts can induce geometrical, compositional, and electronic effects that can be applied to modulate catalytically active sites and consequently accelerate reaction kinetics. Here, a core‐shell heterostructure catalyst consisting of crystalline molybdenum phosphide (MoP) cores and amorphous tungsten oxide (WOx) shells on porous carbon nanosheets (PCN) is developed for oxidative desulfurization (ODS) of fuels. The strongly coupled core‐shell heterogeneous interface triggers a distinctive atomic permeation effect that induces substantial electron transfer from MoP to WOx and subsequent generation of electron‐rich W sites, consequently optimizing the adsorption of intermediates and substrates. The resulting catalyst (WOx@MoP/PCN) demonstrates a turnover frequency as high as 768.1 h−1 for ODS at 60 °C, exceeding that of almost all the state‐of‐the‐art ODS catalysts by 1–2 orders of magnitude. Moreover, a novel surface oxidation pathway based on direct electron transfer is identified in the WOx@MoP/PCN‐H2O2 system, which bypasses the formation of reactive oxygen species, consequently endowing the system with a moderate redox potential. Thus, WOx@MoP/PCN exhibits unprecedented selectivity, achieving 100% removal of thiophenic sulfides from real diesel with minimal consumption of oxidant. [ABSTRACT FROM AUTHOR]

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This work unveils a route for a new generation of heterogeneous polyoxometalate (POMs) based catalysts associated to the preparation of hybrid materials as a triad of POMs, mesoporous silica (SBA‐15) and microporous MOF structures (MOF‐808). The prepared catalyst, PMo12@MOF‐808@SBA‐15, with the main active center the phosphomolybdic acid (PMo12), was successfully applied for the desulfurization of a multicomponent fuel. Its oxidative catalytic performance showed to be considerable superior to the isolated POM@MOF and able to be recycled for more catalytic cycles without active loss. The higher catalytic performance seems to be directly related with the preparation of a more amorphous MOF structure within the channels of SBA‐15, in the presence of active POM guests. [ABSTRACT FROM AUTHOR]

In recent years, TiO2-based catalysts have received extensive attention from researchers for their excellent oxidative desulfurization (ODS) performances. In this paper, a series of mesoporous TiO2/SiO2 catalysts with different TiO2 loadings are prepared, using an incipient wetness impregnation method with agricultural waste rice husk as both the silicon source and mesoporous template and tetrabutyl titanate as the titanium source. The effect of different TiO2 loadings on the ODS performance of the samples is investigated, and the appropriate TiO2 loading is 2.5%. Compared with pure TiO2, the 2.5%TiO2/SiO2 sample exhibits high catalytic activity for oxidative desulfurization. This is, on the one hand, due to the high specific surface area and mesopore volume of the 2.5%TiO2/SiO2 sample. On the other hand, it is due to the uniform dispersion of TiO2 grains with an average diameter of 6.1 nm on the surface of the mesoporous SiO2 carrier, which greatly increases the active sites of the 2.5%TiO2/SiO2 sample, thus improving the catalytic activity of the sample. The recycling performances of the 2.5%TiO2/SiO2 sample are further investigated. The results show that, after fifteen cycles, the 2.5%TiO2/SiO2 sample still maintains high conversions of dibenzothiophene (99.8%) and 4,6-dimethyldibenzothiophene (99.7%) without deactivation. In addition, the 2.5%TiO2/SiO2 sample treated with TBHP aqueous solution is characterized by the technique of UV-Vis, and the Ti-peroxo (Ti-OOtBu) species, the active intermediate for the ODS of bulky organic sulfides, is successfully captured. Finally, a possible reaction mechanism for the ODS process over the 2.5%TiO2/SiO2 sample is proposed. [ABSTRACT FROM AUTHOR]

The presence of sulfur compounds in the chemical industry poses significant environmental and economic problems, including endangering human and animal lives and damaging equipment. For this purpose, hierarchical HY zeolite (Hie‐Y) with a SiO2/Al2O3 molar ratio 10 was successfully synthesized through sequential desilication‐dealumination using NH4OH treatment. A weak alkaline media with surfactant cetyltrimethylammonium bromide (CTAB) facilitates mesoporosity formation and preserves the zeolite structure. Metal oxide (CuO, MoO3) ‐ hierarchical HY zeolite nanocomposites have been prepared by one or a combination of 3 methods: 1) ion exchange, 2) precipitation, and 3) calcination. The obtained catalysts were characterized using XRD, FT‐IR, FESEM, UV‐Vis, EDS, and BET techniques. The formation of a hierarchical structure is associated with structure preservation, but partial destruction occurs based on the entering Cu in the zeolite pores. These catalysts have been studied in the oxidative desulfurization (ODS) reaction. Several parameters, including temperature, catalyst amount, DBT concentration, and reaction time, were evaluated in ODS using the Taguchi Design of Experiments. Catalytic activity order was obtained as Y

Producing an eco-friendly fuel with the least amount of sulfur compounds has been an ongoing issue for petroleum refineries. In this study, bentonite (which is a cheap material and is locally available in abundance) is employed to prepare a nano-silica catalyst with a high surface area to be used for the oxidative desulfurization of kerosene. Two composite catalysts of Fe/silica were supported on CAT-1 (0% HY-zeolite and 100% nano-silica) and CAT-2 (20% HY-zeolite and 80% nano-silica). The activity of the catalysts was evaluated in a batch ODS (oxidative desulfurization) process at temperatures of 30, 60, 90, and 120 °C, a pressure of 1 atm, and a reaction time of 30, 60, 90, and 120 min using 120 L/h of air as the oxidant. The results revealed that the highest total sulfur removal efficiency was 50% and 87.88% for 100% nano-silica (CAT-1) and 80% nano-silica (CAT-2), respectively. The experimental data were then used to construct and validate an accurate mathematical model of the process. The operational parameters for eliminating more than 99% of sulfur and producing eco-friendly fuel were then achieved by using the model. The testing methods for these characterizing materials included X-ray diffraction (XRD), thermal gravimetric examination (TGA), X-ray fluorescence (XRF), and surface area (BET). The outcomes indicated that the addition of HY-zeolite increased the activity of the catalyst (CAT-2 > CAT-1). [ABSTRACT FROM AUTHOR]

The emission of sulfur compounds during the combustion of coal is the main cause of atmospheric pollution and poses a threat to human health and the ecosystem. Thus, elimination of sulfur compounds from coal before its use is compulsory, and hence, coal desulfurization has become the key solution. In the present study, ultrasonic-assisted oxidative desulfurization of coal was conducted utilizing H2O2 in the presence of choline chloride/Acetic acid (ChCl/AcA) deep eutectic solvents (DESs). Three coal samples from different areas of Punjab were received for the investigation. The DES ChCl/AcA possesses sulfur removal efficiency of up to 58–64% pyritic sulfur, 54–63% sulfate sulfur, and 48–54% total sulfur from different coal samples. In addition to inorganic sulfur removal, a considerable decrease in organic sulfur 38–41% has been obtained using ultrasound-assisted oxidative desulfurization. FTIR study has shown that the treated coal samples have decreased sulfur contents as compared to untreated coal samples along with no significant change in the calorific values. These outcomes open new paths headed for more energy-effective and cleaner coal, utilizing cost-effective DESs. [ABSTRACT FROM AUTHOR]

Machine learning algorithms have gained popularity recently as a method for predicting the efficiency of industrial processes. The fluctuation of desulfurization process operation conditions, especially sulfur content in diesel fuel, has an impact on the efficiency of the process. This study presents the development of an artificial neural network (ANN) model using Python to predict the efficiency of the oxidative desulfurization (ODS) process in highly sour diesel fuel. Experimental data from a trickle bed reactor were used to train and validate the model. The dataset included variables such as ODS temperature, pressure, liquid hourly space velocity (LHSV), and sulfur content in the feed. The ANN model demonstrated a high prediction accuracy with sulfur conversion results matching the experimental data with approximately 98% accuracy and a regression coefficient (R²) of 0.99. The model effectively captured the influence of the operating conditions, showing that higher temperatures and pressures significantly enhanced the desulfurization efficiency. Additionally, the optimization of LHSV contributed to achieving optimal sulfur removal. This work highlights the potential of machine learning techniques in enhancing the predictive capabilities and efficiency of industrial desulfurization processes. [ABSTRACT FROM AUTHOR]

To obtain clean fuel, synthesis and characterization of a novel nanocomposite based on mono CdII‐substituted silicotungstate (K3SiW11CdO39), cobalt ferrite (CoFe2O4), and polyaniline (PAN) was presented for the first time. K3SiW11CdO39@CoFe2O4@PAN was identified by FT‐IR, XRD, SEM, and EDX techniques. The outcomes of the characterizations have shown that K3SiW11CdO39 and CoFe2O4 are uniformly dispersed on the PAN surface. The K3SiW11CdO39@CoFe2O4@PAN was employed as a heterogeneous catalyst in the extractive coupled oxidative desulfurization (ECOD) of both real gasoline and dibenzothiophene (DBT) as a thiophenic model fuel. Under relatively mild reaction conditions, the catalytic performance of the as‐prepared nanocatalyst in the ECOD procedure was studied by incorporating acetic acid/hydrogen proxied as an oxidant system at a volume ratio of 1:2. Based on the results, the K3SiW11CdO39@CoFe2O4@PAN nanocatalyst demonstrated effectiveness of up to 95% with 0.1 g at 35°C under optimal operating conditions in the ECOD process. Additionally, the synthesized nanocatalyst exhibited the ability to undergo five consecutive runs in the ECOD process without any discernible reduction in its activity. [ABSTRACT FROM AUTHOR]

In order to solve the adverse effects of sulfur oxides (SOx) released during the combustion process on the environment, health and economy, oxidative deep desulfurization of diesel has become a hotspot all over the world. In this paper, HY@TiO2-x composite catalysts with different TiO2 contents were synthesised by liquid-phase deposition using HY zeolite as the parent material. The catalysts were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Ultraviolet–Visible Diffuse Reflectance (UV–vis), Raman Spectroscopy, Scanning Electron Microscopy (SEM), N2-physisorption, X-ray Photoelectron Spectroscopy (XPS). The characterization results of XRD, FT-IR, UV–vis and Raman showed that TiO2 was successfully loaded on HY zeolite. The catalysts were applied to the oxidative desulfurization (ODS) and adsorption desulfurization of benzothiophene (BT) and dibenzothiophene (DBT). Under the selected reaction condition: T = 70℃, n(H2O2)/n(Sulfur) = 6, moil: mcatalyst = 35: 1. The results show that the HY@TiO2-1.5 catalyst has the best oxidation activity, and the conversion rates of BT and DBT were 85.0% and 99.7%, respectively. Meanwhile, the adsorption of BT and DBT were 5.06 and 10.93 mg-S/g-Cat. respectively. HY@TiO2-1.5 catalyst is simple to prepare, with a high activity of bulky organic sulfides adsorption-oxidative desulfurization and has a potential application in oil refining. The reasons for the improvement of organic sulfide adsorption and oxidative desulfurization activity on HY @ TiO2-1.5 catalyst are discussed. [ABSTRACT FROM AUTHOR]

Titanium modified UiO-66(Zr)-type metal–organic framework (MOF) nanophotocatalysts have been prepared via a modified one-step solvothermal methodology and evaluated in photocatalytic oxidative desulfurization. Extensive characterization by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence spectroscopy (PL), nitrogen adsorption–desorption, and thermogravimetric analysis (TGA), have revealed the role of Ti loading, on Ti speciation and the structure of the synthesized materials. The performance of nanophotocatalysts have been evaluated for photocatalytic oxidative desulfurization (PODS). PODS reaction parameters, including temperature, photocatalyst dosage, oxidant to sulfur ratio, and solvent to fuel ratio, were optimized, with dibenzothiophene (DBT) conversion reaching 100% under optimal conditions (T = 50 °C, photocatalyst dosage = 2 g/L, oxidant to sulfur molar ratio (O/S = 8), and solvent/fuel = 1). Recyclability studies performed for the optimal catalyst showed good stability over six recycles, with total conversion dropping by only 18%. Kinetic studies showed that DBT PODS follows pseudo-first-order kinetics, with an activation energy value of 55.1 kJ mol−1. [ABSTRACT FROM AUTHOR]

The primary objective of this investigation was to develop a new nanocatalyst that could produce materials with a lower sulfur content, thereby reducing its environmental harm. To achieve this, the researchers used the sol‐gel method to synthesize a heterogeneous nanocatalyst by attaching sandwich‐type polyoxotungstate [(CuW9O34)2Cu4(H2O)2−10] (denoted as Cu6W18O70) clusters on the surface of copper ferrite nanoparticles (CuFe2O4 NPs). To characterize the nanocatalyst, several analysis techniques were employed, including Fourier transform infrared spectroscopy, ultraviolet‐visible, powder X‐ray diffraction, and scanning electron microscope. The oxidative desulfurization of hazardous sulfur‐containing real and model fuel oils was effectively catalyzed by the Cu6W18O70⊂CuFe2O4 nanocatalyst. According to the experimental findings, the best efficiencies in oxidation reaction were achieved in 1 h contracting time at 35°C, which was as high as 95%. The Cu6W18O70⊂CuFe2O4 nanocatalyst exhibited impressive removal rates (%) on dibenzothiophene (C12H8S), benzothiophene (C8H6S), and thiophene (C4H4S) of model fuels, with figures reaching 97%, 96% and, 96% respectively. Furthermore, multiple recycling of the uniform nanocatalyst can be achieved effortlessly through filtration, without experiencing any notable decline in activity. Therefore, the authors suggest that this study will pave the way for the widely used mentioned nanocatalyst in the practical and workable organization of petroleum fractions. [ABSTRACT FROM AUTHOR]

Catalytic oxidative desulfurization (ODS) using titanium silicate catalysts has emerged as an efficient technique for the complete removal of organosulfur compounds from automotive fuels. However, the precise control of highly accessible and stable-framework Ti active sites remains highly challenging. Here we reveal for the first time by using density functional theory calculations that framework hexa-coordinated Ti (TiO6) species of mesoporous titanium silicates are the most active sites for ODS and lead to a lower-energy pathway of ODS. A novel method to achieve highly accessible and homogeneously distributed framework TiO6 active single sites at the mesoporous surface has been developed. Such surface framework TiO6 species exhibit an exceptional ODS performance. A removal of 920 ppm of benzothiophene is achieved at 60°C in 60 min, which is 1.67 times that of the best catalyst reported so far. For bulky molecules such as 4,6-dimethyldibenzothiophene (DMDBT), it takes only 3 min to remove 500 ppm of DMDBT at 60°C with our catalyst, which is five times faster than that with the current best catalyst. Such a catalyst can be easily upscaled and could be used for concrete industrial application in the ODS of bulky organosulfur compounds with minimized energy consumption and high reaction efficiency. [ABSTRACT FROM AUTHOR]

A binuclear dioxomolybdenum catalyst [(MoO2Cl2)2(L)] (1) (with L (1S,2S)-N,N′-bis(2-pyridinecarboxamide)-1,2-cyclohexane) was prepared and used as catalyst for the desulfurization of a multicomponent model fuel containing the most refractory sulfur compounds in real fuels. This complex was shown to have a high efficiency to oxidize the aromatic benzothiophene derivative compounds present in fuels, mainly using a biphasic 1:1 model fuel/MeOH system. This process conciliates catalytic oxidative and extractive desulfurization, resulting in the oxidation of the sulfur compounds in the polar organic solvent. The oxidative catalytic performance of (1) was shown to be influenced by the presence of water in the system. Using 50% aq. H2O2, it was possible to reuse the catalyst and the extraction solvent, MeOH, during ten consecutive cycles without loss of desulfurization efficiency. [ABSTRACT FROM AUTHOR]

A highly efficient oxidative desulfurization composite catalyst NH2‐Uio‐66‐Mo has been prepared and applied in the catalytic oxidative desulfurization. It was elucidated that Mo6+ could increase the oxygen vacancies and active sites on the catalyst and increase the pore size of UiO‐66. Meanwhile, the removal rate of dibenzothiophene (DBT) reached 99.2 % after 60 min under optimal conditions and remained above 90 % after 5 cycles, showing the composite catalyst's remarkable catalytic performance and satisfactory reusability NH2‐UiO‐66‐Mo. In addition, kinetic studies revealed that the desulfurization process can present a pseudo‐first‐order kinetic process. The apparent activation energy was 10.6 kJ/mol. Finally, in combination with oxides, possible oxidation pathways were identified. [ABSTRACT FROM AUTHOR]

3D-printed monolithic catalysts have attracted extensive attention in the petrochemical industry due to significant advantages of excellent circulation, mass and heat transfer efficiency and convenience. However, according to the characteristics of each chemical reaction, there are diversity and difficulty in the design of monolithic catalysts, especially the regulation of catalyst ink, the introduction of active centers and the construction of reaction pores. In this work, we report a preparation of ceramic-based catalysts with direct ink writing (DIW) 3D printing technology for ultra-deep oxidative desulfurization (ODS) of diesel. Through a series of rheological analyses of catalyst inks, the effects of ink composition and content on fluidity and viscoelasticity are explored for the forming mechanism of high-quality 3D printed inks. Besides, ionic liquids (ILs) [C 12 Vim] 3 PMo 12 O 40 and mordenite are cleverly introduced into the 3D printed ink for assisted construction of active center and reaction channel in functionalization of the ODS catalyst. The DBT removal of 3D-MoO 3 /BT-MOR can reach 100 % and this monolithic catalyst is easy to be separated from oil. This work is deeply focused on the preparation and molding of catalyst inks to achieve efficient monolithic catalysts that provide an excellent path for many industrial oxidation reactions. [ABSTRACT FROM AUTHOR]

Clean fuel production with strict limit on toxic contaminants is one of the most important aims for petroleum refinery industry regarding the improvement of environmental conditions. In this study, oxidative desulfurization (ODS) process has been used to achieve such goal. For this purpose, a new and efficient synthetic composite mesoporous nano-catalyst has been designed by enhancing morphological and mechanical properties of gamma alumina (γ-Al2O3) on a carbon nano fiber (CNF) as multiple supports. Four different catalysts based on different amount of CNF have been designed. X-Ray diffraction (XRD), X-Ray fluorescence (XRF), crash strength test, thermal gravimetric examination (TGA), and surface area (BET) have been used to characterize the catalysts. The catalyst with 10% loading of CNF (CAT-3) has been found to increase the tensile strength by more than 200% compared to the CNF-free sample (CAT-4). Then, a series of experiments has been conducted in a batch ODS reactor with air as an oxidant and light gas oil (LGO) as a real feedstock to evaluate the effectiveness of the designed catalysts and the performance of the reactor. The new catalyst has been clearly shown to be a significant factor in sulfur removal resulting in a clean fuel. [ABSTRACT FROM AUTHOR]

Desulfurization technology plays an essential role in the removal of sulfur existing in raw fuel for an immediate aversion of the formation of acid rain and sulfate particulate matters that endanger the environment and public health. In this study, CeO2–WOx–TiO2 catalyst was synthesized by sol–gel method and applied in the oxidative desulfurization of fuel oil using H2O2 as oxidizing agent. The WOx loading (0.10–0.40 mol fraction) was varied, and the CeO2–WOx–TiO2 catalyst was characterized by energy-dispersive X-ray and scanning electron microscopy. The effect of different parameters such as catalyst dosage (0.1–0.5 g), oxidation time (10–40 min) and quantity of phase transfer agent dosage (0.1–0.5 g) on the dibenzothiophene conversion was investigated. Results show that increasing the oxidation temperature, dosage of both catalyst and phase transfer agent, and oxidation time would result in higher dibenzothiophene conversion from refractory fuel oil. The oxidative desulfurization of fuel oil using CeO2–WOx–TiO2 catalyst exhibited a 100% dibenzothiophene conversion at temperature of 60 ºC, reaction time of 30 min, dosage of catalyst at 0.2 g and phase transfer agent at 0.1 g. Results showed the mole fraction of 0.3 W in CeO2–WOx–TiO2 catalyst provided the highest efficiency in dibenzothiophene conversion, which is essential in industrial applications specifically for oxidative desulfurization of fuel oil. The results in this research support the novel application of the CeO2–WOx–TiO2 catalyst in producing clean fuels in conjunction with the oxidative desulfurization process. Therefore, the catalyst synthesis in this study provides a prospective usability for future industrial applications in the aspect of desulfurization. The present work demonstrates the feasibility of using CeO2–WOx–TiO2 catalyst in oxidative desulfurization to generate desulfurized fuel oil, which is a more economical approach since the process operates at lower temperature and pressure. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of hierarchically porous amino-functionalized Zr-MOFs (HP-UiO-66-NH 2 -X) anchored phosphomolybdic acid catalysts have been synthesized by a template-free method. • PMA/HP-UiO-66-NH 2 -9 with an average mesopore size of 4.0 nm exhibits the highest catalytic ODS activity. • DFT results indicate that the electron transfer (from amino group to PMA) makes PMA react more easily with H 2 O 2 , thereby generating more •OH radical to promote the ODS reaction. • Monolithic PMA/HP-UiO-66-NH 2 @CMC is prepared as shaping ODS catalyst to meet industrial application needs. The applications of hierarchically porous metal–organic frameworks (HP-MOFs) against traditional microporous counterparts for oxidative desulfurization (ODS) have triggered wide research interests due to their highly exposed accessible active sites and fast mass transfer of substrate molecules, particularly for the large-sized refractory sulfur compounds. Herein, a series of hierarchically porous amino-functionalized Zr-MOFs (HP-UiO-66-NH 2 -X) network with controllable mesopore sizes (3.5–9.2 nm) were firstly prepared through a template-free method, which were further utilized as anchoring support to bind the active phosphomolybdic acid (PMA) via the strong host–guest interaction to catalyze the ODS reaction. Benefitting from the hierarchically porous structure, accessible active sites and the strong host–guest interaction, the resultant PMA/HP-UiO-66-NH 2 -X exhibited excellent ODS performance, of which, the PMA/HP-UiO-66-NH 2 -9 with an appropriate mesopore size (4.0 nm) showed the highest catalytic activity, achieving a 99.9% removal of dibenzothiophene (DBT) within 60 min at 50 °C, far exceeding the microporous sample and PMA/HP-UiO-66. Furthermore, the scavenger experiments confirmed that •OH radical was the main reactive species and the density functional theory (DFT) calculations revealed that electron transfer (from amino group to PMA) made PMA react more easily with oxidant, thereby generating more •OH radical to promote the ODS reaction. Finally, from the industrial point of view, the powdered MOF nanoparticles (NPs) were in situ grown on the carboxymethyl cellulose (CMC) substrates and shaped into monolithic MOF-based catalysts, which still exhibited satisfying ODS performance in the case of model real fuel with good reusability, indicating its potential industrial application prospect. [ABSTRACT FROM AUTHOR]

Modification of photocatalysts to improve their adsorption and photocatalytic activity in the oxidative desulfurization of liquid fuels has been reported by many investigators. In this study, Pt-decorated carbon-doped TiO2 nanoparticles were synthesized by hydrothermal and photo-deposition techniques and were subsequently used in photocatalytic oxidative desulfurization of dibenzothiophene (DBT) in n-heptane as a simulated liquid fuel with methanol as the extracting solvent. Carbon-doped TiO2 was first synthesized by a simple self-doping method. Pt was then loaded by a photo-deposition technique. The synthesized photocatalysts (labeled as YPt-CT where Y is percent Pt loading) were characterized by of X-ray diffraction (XRD), photoluminescence (PL), field emission scanning electron microscopy (FESEM), N2-physisorption, UV-Vis diffusive reflectance spectra (UV-Vis DRS), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), and nitrogen sorption measurements. The removal efficiency of DBT was 98% in the presence of 2 g/l of 0.5Pt-CT catalyst under visible-light irradiation (λ > 400 nm), ambient pressure, and reaction temperature of 40°C. [ABSTRACT FROM AUTHOR]

The desulfurization of oil must be resolved as soon as possible due to a variety of issues, including environmental contamination and protection regulations. It was believed that oxidative desulfurization (ODS) was the most promising method. In this research, metal oxide-based layered double hydroxides (TiO2@Ni-Al and ZnO@Ni-Al) were effectively synthesized for the ODS of 4-methyldibenzothiophene (4-MDBT). TiO2@Ni-Al and ZnO@Ni-Al exhibited superior catalytic performance and high recycling capacity, achieving a 99% removal rate after five reactions in 30 min. The heterogeneous catalyst TiO2@Ni-Al/ZnO@Ni-Al is easy to separate and recover from a reaction system. Increased temperature facilitates the transformation of 4-MDBT into 4-MDBTO2. The influence of H2O2's rapid decomposition rate, which can inhibit oxidation reactions, reduces the catalytic activity as the temperature increases. 4-MDBT Sulphur removal on TiO2@Ni-Al and ZnO@Ni-Al is 99.48 and 99.51%, respectively. TiO2@Ni-Al and ZnO@Ni-Al have great potential for use in the industry based on these results. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

A new high yield and inexpensive composite was fabricated by supporting tungsten oxide on metakaolin via the incipient wetness impregnation method to use in oxidative desulfurization reaction and produce ultra‐clean fuel. The prepared catalyst was characterized by various techniques like XRD, FTIR, FESEM, EDX and N2 adsorption–desorption isotherms, which indicated the catalyst was properly constructed. Initially, desulfurization was examined by loading different amounts of tungsten on the metakaolin surface. Based on the results, 15 % W/metakaolin showed high catalytic activity for the model and real fuels. Moreover, the influence of the main operating variables was studied through the Box–Behnken experimental design. The maximum sulfur removal reached to 99.3 % at a reaction temperature of 60 °C, oxidant to sulfur molar ratio12, catalyst dosage 0.04 g and oxidation time 40 min. Desulfurization from gasoline and gas oil with initial sulfur contents of 300 ppm and 7550 ppm was done under optimum conditions, which represented an efficiency of 60 % and 74 %, respectively. Performing the recycling tests proved the great durability of the catalyst after five runs. This research sheds light that the employed catalyst has excellent activity for industrial applications in the desulfurization process. [ABSTRACT FROM AUTHOR]

In this research, a simultaneous catalytic extraction–oxidation system for model and real fuel desulfurization has been investigated. To do this, the vanadium–chromium catalysts were supported on a mesoporous silica substrate (KIT-6) by a two-step impregnation method. Different analyses such as FT-IR, XRD, SEM, TEM, ICP, BET, elemental mapping, EDX, and TPR were used to characterize catalysts. According to the obtained results, the catalyst with maximum vanadium oxide content (CVK-C) showed the highest catalytic activity for the removal of dibenzothiophene from the model fuel and sulfur-containing compounds from the real fuel (gasoline) in the oxidative desulfurization process. In this catalytic system, the reaction was carried out under different conditions such as the amount of catalyst, type of catalyst, temperature, time, oxidizing value, type of extracting solvent, and the ratio of extracting solvent to model fuel. Under optimal conditions, the removal of dibenzothiophene was 97% from model fuel (n-octane) and the removal of sulfur-containing compounds from the real fuel was above 90%. The catalyst can be recovered up to 4 times without significant reduction in catalytic activity. [ABSTRACT FROM AUTHOR]

Synergic catalytic effect between active sites and supports greatly determines the catalytic activity for the aerobic oxidative desulfurization of fuel oils. In this work, Ni-doped Co-based bimetallic metalorganic framework (CoNi-MOF) is fabricated to disperse N-hydroxyphthalimide (NHPI), in which the whole catalyst provides plentiful synergic catalytic effect to improve the performance of oxidative desulfurization (ODS). As a bimetallic MOF, the second metal Ni doping results in the flower-like morphology and the modification of electronic properties, which ensure the exposure of NHPI and strengthen the synergistic effect of the overall catalyst. Compared with the monometallic Co-MOF and naked NHPI, the NHPI@CoNi-MOF triggers the efficient activation of molecular oxygen and improves the ODS performance without an initiator. The sulfur removal of dibenzothiophene-based model oil reaches 96.4% over the NHPI@CoNi-MOF catalyst in 8 h of reaction. Furthermore, the catalytic product of this aerobic ODS reaction is sulfone, which is adsorbed on the catalyst surface due to the difference in polarity. This work provides new insight and strategy for the design of a strong synergic catalytic effect between NHPI and bimetallic supports toward high-activity aerobic ODS materials. [ABSTRACT FROM AUTHOR]

Recently, supported WO3-based catalysts have been widely used in oxidative desulfurization (ODS) due to their advantages of easy separation, high activity, and being environment-friendly. In this work, supported mesoporous WO3/SiO2 catalysts have been prepared using an incipient-wetness impregnation method with agricultural waste rice husks as both a silicon source and mesoporous template, and phosphotungstic acid as a tungsten source. The effects of different calcination temperatures and WO3 loadings on the ODS performance of samples are studied, and the appropriate calcination temperature and WO3 loading are 923 K and 15.0 wt.%, respectively. The relevant characterization results show that, compared with pure WO3, the specific surface area and mesopore volume of WO3/SiO2 samples are greatly increased. Due to (a) high WO3 loading, (b) high specific surface area, and (c) nanoscale WO3 grains uniformly dispersed on the surface of the mesoporous SiO2 carrier, active sites of WO3/SiO2 catalysts are greatly increased, and their catalytic activities are improved. After the sixth and eighth runs in the ODS of dibenzothiophene and 4,6-dimethyldibenzothiophene, respectively, the WO3/SiO2 catalyst still maintains high catalytic activity (>99.0%) despite the presence of a partial loss of WO3. In addition, with the aid of the UV-Vis technique, the tungsten-peroxo species, the active intermediates in the ODS reaction catalyzed by the WO3/SiO2 catalyst, are captured. Finally, a possible mechanism for the ODS of bulky organic sulfides using the WO3/SiO2 catalyst is proposed. [ABSTRACT FROM AUTHOR]

The aim of this study is to predict the efficiency of oxidative desulfurization method (in a gas–liquid oxidation system) for gas condensate using artificial intelligence (AI) systems such as Fuzzy Inference System, Adaptive Neuro-Fuzzy Inference System (ANFIS), Genetic Algorithm (GA)-Fuzzy, and GA-ANFIS. The method utilizes mixtures of H2SO4, HNO3, and NO2 as oxidant agents in various amounts. The optimal parameters of the proposed models were determined using GA, and statistical parameters such as mean absolute error, average relative deviation, and correlation coefficient were used to compare the models. The correlation coefficients for Fuzzy, ANFIS, GA-Fuzzy, and GA-ANFIS models were found to be 0.5899, 0.7831, 0.9693, and 0.9687, respectively. The results indicated that ANFIS-GA and Fuzzy-GA models can effectively predict the desulfurization efficiency of the novel technique. Furthermore, the use of GA improved the performance of the Fuzzy and ANFIS models and enhanced their prediction accuracy. Overall, this study demonstrates the potential of AI systems in predicting the efficiency of novel chemical methods for industrial applications. [ABSTRACT FROM AUTHOR]

This research endeavors to address the pressing challenge of reducing sulfur content in fuels, an environmental imperative. It does so by employing bimetallic catalysts to enhance the efficiency of oxidative desulfurization (ODS) processes. This involves utilizing successive impregnation and co-impregnation methods to prepare a MoO3-V2O5/Al2O3. The catalysts underwent characterization using various techniques including X-ray diffraction (XRD), N2 adsorption–desorption, UV–vis (DRS), temperature-programmed desorption (NH3-TPD), Raman, Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and energy dispersive spectrum (EDS). The catalyst was utilized for the evaluation of the ODS process of dibenzothiophene (DBT). The effects of oxidants, namely H2O2 and t-butyl hydroperoxide (TBHP), were studied in the ODS. The catalyst prepared using the co-impregnation method (5M-15V-co) demonstrated significant acidic sites and exhibited remarkable efficiency in oxidative desulfurization. Remarkably, this catalyst achieved 100% oxidation of sulfur components within 30 min (min). To assess the catalyst's performance further, competitive compounds including nitrogen-containing compounds (NCCs) and saturated and unsaturated hydrocarbon compounds (HCs) were employed in the ODS. Initially, the introduction of NCCs led to a decrease in the sulfur removal rate; however, the catalyst successfully oxidized DBT completely within 60 min. When cyclohexene was present as an olefinic hydrocarbon compound, the catalyst oxidized DBT by approximately 75%, whereas DBT oxidation reached 100% within 20 min when p-xylene was introduced to the catalytic reactor. Additionally, as the O/S ratio increased from 2/5 to 10, the sulfur removal rate improved from 30 to 90%, indicating that HCs and NCCs compete with sulfur in terms of oxidant consumption. [ABSTRACT FROM AUTHOR]

Aerobic oxidative desulfurization (AODS) represents a promising approach to achieving deep desulfurization in petroleum products. Hexagonal boron nitride (hBN) has gained increasing attention as a metal-free catalyst for AODS, offering advantages such as thermal stability, nontoxicity, and environmental friendliness. Despite recent research having highlighted the potential of BN nanocatalysts in AODS, there is a lack of in-depth studies on how micromorphological and structural changes in these BN nanocatalysts influence their AODS performance. In light of this, this paper introduces two distinct 1D BN catalysts, namely, BN nanofibers (BNNFs) and BN microfibers (BNMFs), into the AODS system. The catalysts prepared by using distinct cooling methods exhibit substantial differences in size, micromorphology, pore structure, and defects. Compared to BNMF catalysts, the BNNFs with decreased diameters on the nanometer scale have a hierarchical porous structure and a high percentage of open pore structure on the surface. This unique structural characteristic proved to be more conducive to the efficient transport and diffusion of DBT molecules, significantly enhancing the AODS performance. In addition, the large number of N defects in BNNFs provides abundant active sites for AODS catalysis, thus exhibiting superior AODS catalytic performance in comparison to BNMFs. Furthermore, BNNFs also exhibit efficient removal rates for other sulfur-containing compounds, such as 4-MDBT and 4,6-DMDBT, achieving complete removal (100%) within 6 h. This study highlights the critical role of microstructures in accelerating the AODS process and provides a valuable framework for optimizing the hBN structures for efficient oxidative desulfurization. [ABSTRACT FROM AUTHOR]

Acidic deep eutectic solvents (DESs) have been considered desirable extractants and catalysts for desulfurization. However, their hydrogen bond donors (HBDs) are usually sole organic acids, which are not conducive to efficient green catalysis. Herein, a novel inorganic–organic dual-acid DES (DADES) was reported for efficient extractive and oxidative desulfurization. Benefiting from the physical interaction among the three components in a DADES, a transparent homogeneous liquid can be obtained even though inorganic acid (boric acid, BA) and organic acid (acetic acid, AA) can be immiscible. Furthermore, the dual-acid HBD can increase the acidity of the DADES and reduce its viscosity, accelerating its mass transfer efficiency and enhancing its catalytic activity. With 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) as the hydrogen bond acceptor, [Bmim]Cl/BA/0.3AA effectively activated hydrogen peroxide and achieved sulfur removal of 96.6% at 40 °C. Furthermore, the universality of the synergistic effect in various DADESs was confirmed by the modulation of the types of organic acids. This study not only motivates the construction of more intriguing novel DESs based on the DADES concept but also highlights their potential in clean fuel production. [ABSTRACT FROM AUTHOR]

A source of Brønsted acid centers, generated on the surface of two mesoporous silica supports of different structures (SBA-15 and MCF), was 3-(trihydroxysilyl)-1-propanesufonic acid (TPS). The materials obtained were characterized and applied as catalysts for the oxidative desulfurization of dibenzothiophene (DBT) with hydrogen peroxide as a model ODS (oxidative desulfurization) process. The properties of the materials were examined via nitrogen physisorption, XRD (X-ray Diffraction) and elemental analysis showing the preservation of the support structure after modification with organosilane species. Due to the aggregation of catalyst particles in the reaction mixture, the SBA-15 based catalyst was not very effective in DBT oxidation. Contrary, TPS/MCF catalyst exhibited a very good activity (almost total conversion of DBT after 1 h in optimized reaction conditions) and stability in dibenzothiophene oxidation in mild reaction conditions. [ABSTRACT FROM AUTHOR]

Oxidative desulfurization from fuel oil is one of the important methods for deep desulfurization. The development of efficient oxidative desulfurization catalysts is crucial for improving the desulfurization performance. Successful encapsulation of phosphotungstic acid (HPW) and ionic liquid (BMImBr) inside the mesoporous cages of MIL-101(Cr) was accomplished through a combination of “bottle around ship” and “ship in bottle” methods. The obtained BMImPW@MIL-101(Cr) composite was characterized by XRD, FTIR, BET, SEM, XPS and ICP methods. Results indicated that the BMImPW@MIL-101(Cr) composites with PW3− loading of 23.1–50.7 wt% were obtained, demonstrating that the “bottle around ship” method is beneficial to make full use of nanocages of MIL-101(Cr) to obtain expected high loading of active PW3−. The BMImPW@MIL-101(Cr) exhibits excellent reusability with no evidence of leaching of active PW3− and BMIm+, and well-preserved structure after successive cycles of regeneration and reuse. The significantly improved stability of BMImPW@MIL-101(Cr) as compared to HPW@MIL-101(Cr) is possibly because the leaching of the active PW3−− sites can be greatly suppressed by forming large size of BMImPW owing to introduction of BMIm+ cation. The BMImPW@MIL-101(Cr) exhibited excellent catalytic activity for solvent free oxidative desulfurization of refractory sulfides. The enhanced oxidative desulfurization activity as compared to HPW@MIL-101(Cr) can be explained by the intimate contact of sulfides with active PW3− sites owing the strong attraction of BMIm+ cation with the sulfides. [ABSTRACT FROM AUTHOR]

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A review of studies in the field of oxidation of organic substrates with sodium hypochlorite, published in the past 15–20 years, is presented. Oxidation of primary and secondary alcohols, epoxidation of olefins, oxidative desulfurization, and nitrogen oxide oxidation are described. A comparative analysis of various catalytic systems used in this field is made. Industrial uses of sodium hypochlorite, in particular, for wastewater treatment, are described. The main directions of using sodium hypochlorite and the related prospects and problems are outlined. [ABSTRACT FROM AUTHOR]

This review provides an analysis of prior research on the oxidation of organic compounds with oxygen as an oxidant in the presence of transition-metal molybdates. The reaction mechanisms suggested for the oxidation of various classes of organic substrates, methods for the synthesis and modification of molybdates, and promising industrial applications of molybdate catalysts are discussed. [ABSTRACT FROM AUTHOR]

Producing an eco-friendly fuel with the least amount of sulfur compounds has been an ongoing issue for petroleum refineries. In this study, bentonite (which is a cheap material and is locally available in abundance) is employed to prepare a nano-silica catalyst with a high surface area to be used for the oxidative desulfurization of kerosene. Two composite catalysts of Fe/silica were supported on CAT-1 (0% HY-zeolite and 100% nano-silica) and CAT-2 (20% HY-zeolite and 80% nano-silica). The activity of the catalysts was evaluated in a batch ODS (oxidative desulfurization) process at temperatures of 30, 60, 90, and 120 °C, a pressure of 1 atm, and a reaction time of 30, 60, 90, and 120 min using 120 L/h of air as the oxidant. The results revealed that the highest total sulfur removal efficiency was 50% and 87.88% for 100% nano-silica (CAT-1) and 80% nano-silica (CAT-2), respectively. The experimental data were then used to construct and validate an accurate mathematical model of the process. The operational parameters for eliminating more than 99% of sulfur and producing eco-friendly fuel were then achieved by using the model. The testing methods for these characterizing materials included X-ray diffraction (XRD), thermal gravimetric examination (TGA), X-ray fluorescence (XRF), and surface area (BET). The outcomes indicated that the addition of HY-zeolite increased the activity of the catalyst (CAT-2 > CAT-1).

In recent years, TiO2-based catalysts have received extensive attention from researchers for their excellent oxidative desulfurization (ODS) performances. In this paper, a series of mesoporous TiO2/SiO2 catalysts with different TiO2 loadings are prepared, using an incipient wetness impregnation method with agricultural waste rice husk as both the silicon source and mesoporous template and tetrabutyl titanate as the titanium source. The effect of different TiO2 loadings on the ODS performance of the samples is investigated, and the appropriate TiO2 loading is 2.5%. Compared with pure TiO2, the 2.5%TiO2/SiO2 sample exhibits high catalytic activity for oxidative desulfurization. This is, on the one hand, due to the high specific surface area and mesopore volume of the 2.5%TiO2/SiO2 sample. On the other hand, it is due to the uniform dispersion of TiO2 grains with an average diameter of 6.1 nm on the surface of the mesoporous SiO2 carrier, which greatly increases the active sites of the 2.5%TiO2/SiO2 sample, thus improving the catalytic activity of the sample. The recycling performances of the 2.5%TiO2/SiO2 sample are further investigated. The results show that, after fifteen cycles, the 2.5%TiO2/SiO2 sample still maintains high conversions of dibenzothiophene (99.8%) and 4,6-dimethyldibenzothiophene (99.7%) without deactivation. In addition, the 2.5%TiO2/SiO2 sample treated with TBHP aqueous solution is characterized by the technique of UV-Vis, and the Ti-peroxo (Ti-OOtBu) species, the active intermediate for the ODS of bulky organic sulfides, is successfully captured. Finally, a possible reaction mechanism for the ODS process over the 2.5%TiO2/SiO2 sample is proposed.

This study investigated the catalytic performance of three polyoxometalates (H3PMo12O40 (PMo), H3PW12O40 (PW) and H4SiW12O40 (SiW)) supported on montmorillonite K10 for deep oxidative desulfurization (ODS) of mixed thiophenic model oil, crude oil, and gasoline. Experimental results revealed that PW exhibited higher activity than PMo and SiW. The best solvent for mixed model oil was found to be EtOH, while MeCN was optimal for crude oil to remove oxidized sulfur compounds in a biphasic system under atmospheric pressure at 75°C in presence of H2O2 as oxidating agent. Using PW/K10 as the catalyst, the conversion of mixed model/EtOH and crude oil/MeCN reached 98.76% and 51.36%, respectively, under optimal conditions for 80 minutes. To investigate the impact of real oil composition on the desulfurization process, various unsaturated and N-compounds (pyrrole and pyridine) were added to mixed model oil. Finally, PW/K10 was recycled five times, and the results indicated no significant decrease in catalytic activity.

The microwave-assisted hydrogen peroxide-citric acid desulfurization of coal was optimized by response surface methodology, and the samples were characterized before and after desulfurization by proximate analysis, ultimate analysis, sulfur forms determination, X-ray diffraction (×RD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (×PS), and scanning electron microscopy (SEM) and so on. The quantum chemical calculations were selected to investigate desulfurization mechanism of microwave-assisted hydrogen peroxide-citric acid, and data analysis shows that the citric acid dose is the main factor affecting the desulfurization rate. Under optimized conditions, the actual desulfurization rate can reach 72.23%, the sulfur removal rate of pyrite up to 92.19%. The mineral content of the coal sample was significantly reduced. The oxygen-containing functional groups in the coal sample increased, and more inorganic sulfur and sulfoxide in the low valence state were oxidized to sulfone and sulfate in the high valence state. The microwave effect of pyrite will react with hydrogen ions to produce Fe2+, Fe2+ and citric acid reaction to form a complex. Quantum chemical calculations prove that the addition of an applied electric field can reduce the energy required for the coordination reaction and facilitate the reaction. [ABSTRACT FROM AUTHOR]

Bimetallic heterogeneous catalysts based on SBA-15 containing molybdenum and iron oxides were studied in the oxidation reactions of model mixtures of organosulfur compounds. The addition of iron (in the form of iron(III) oxide) in an amount of 0.05 wt % to the catalyst 5% Mo/SBA-15 was the most effective. The catalysts were characterized by a complex of physicochemical methods: low-temperature adsorption–desorption of nitrogen, X-ray diffraction analysis, transmission electron microscopy, and X-ray photoelectron spectroscopy. The influence of the main oxidation parameters (reaction time, temperature, composition and amount of catalyst, and amount of oxidizing agent) on the conversion of dibenzothiophene as a component of the model mixture was investigated. Optimal oxidation conditions were selected to achieve the total conversion of the substrate: the molar ratio H2O2 : S = 2 : 1, 0.5 wt % FeMo/SBA-15 catalyst, 60 min, and 60°C. Catalysts can be used for at least five cycles without loss of activity during their intermediate washing from oxidation products. [ABSTRACT FROM AUTHOR]