Oxidative Desulfurization Of Model Oil Research Articles

Choline-based Deep Eutectic Solvent for Extractive Oxidative Desulfurization of Model Oil

One of the hardest processes encountered by petroleum refining is sulfur elimination from fuel oil. There are many traditional methods executed but they caused drawbacks such as poor selectivity of sulfur compounds and toxic raw materials. Extractive oxidative desulfurization (EODS) caught the interest of researchers due to high selectivity of sulfur compounds and great desulfurization. Currently, researchers are investigating the use of ionic liquids (ILs) as green extractant, unfortunately they are expensive. This research is proposing and comparing the use of cheap biodegradable solvents called deep eutectic solvents (DESs), as extractants in removing sulfur from fuel oil. The DESs are synthesized through a combination of choline chloride - orcinol and choline chloride - ethylene glycol, and their structure is confirmed through FTIR. Their thermal properties are characterized by DSC and TGA. Their desulfurization performance is evaluated by type of DESs, different ratios of DES and model oil, different ratios of oxidant and sulfone and various temperatures which these factors are found to influence the result. The optimum conditions are found to be at 1:1 for DES and model oil ratio, 4 for O/S ratio and temperature at 85 °C with the extraction efficiency of 99.98%. In conclusion, this DES has high potential to be the cheap green alternative to the conventional extractant for extractive oxidative desulfurization process.

Oxidative desulfurization of model oil over the bowl-shaped N-doped carbon material loaded by the defective silicotungstic acid

The Keggin-type silicotungstic acid (SiW12) with oxygen vacancies (Ov) defects was facilely supported on the bowl-shaped N-doped carbon (NC) material through the one-step carbonization of the precursor consisting of acryloxyethyl trimethylammonium chloride gel microspheres (CPDAC) and intact SiW12 in air. The catalyst SiW12/NC prepared at a calcination temperature of 400 °C showed an outstanding oxidative desulfurization (ODS) performance with H2O2, due to the Ov defect SiW12 with high activity and its excellent dispersion in NC as well as more exposed active sites. Consequently, dibenzothiophene (DBT) in model oil could be almost completely removed within 20 min at 60 °C with a high kinetic constant (0.2034 min−1) and low apparent activation energy (38.06 kJ/mol). In addition, based on the radical experiments, a HO radical mechanism for ODS reaction of model oil over SiW12/NC-400 was mainly uncovered. Furthermore, SiW12/NC-400 could be reused for 7 cycles with no significant loss of activity.

Oxidative desulfurization of model and real fuel samples with natural zeolite-based catalysts: experimental design and optimization by Box–Behnken method

Abstract In this study, oxidative desulfurization was performed on simulated oil fraction consist of 1000 ppm dibenzothiophene. Cobalt supported on natural zeolite of Kaolin has been used as heterogeneous catalysts. 10% Co/metaKaolin with hydrogen peroxide as oxidant and acetonitrile as extraction solvent have shown excellent performance on desulfurization. Response surface methodology in experimental design and its subset Box–Benken was used to evaluate the performance of the selected catalyst in different operating conditions such as temperature, oxidant to sulfur molar ratio, time and catalyst amount. Also, optimum conditions was obtained are equal to 60 °C, O/S molar ratio (10.8 mol/mol), time (46 min) and catalyst amount 0.04 g with 97.1% sulfur removal. Oxidative desulfurization of model oil containing 1000 ppm of each sulfur component benzothiophene and thiophene was also tested at the optimum conditions, Oxidative desulfurization yield was ordered as DBT > BT > Th. In addition, after four steps consecutive recycle under optimum conditions oxidative desulfurization capacity of 10% Co/metaKaolin catalyst decreased from 97% to 92%, which is still high desulfurization capability. Finally, the performance of 10% Co/metaKaolin catalyst in oxidative desulfurization was evaluated for real oil fractions, gasoline and gasoil that was provided from regional oil refinery with sulfur content of 286 ppm and 7900 ppm, respectively. At the optimum conditions of operating variables desulfurization yield was 58% and 79% of total sulfur removal for gasoline and gasoil respectively with no significant changes in fuels properties.

Cobalt-based sandwich-type polyoxometalate supported on amino-silane decorated magnetic graphene oxide: A recoverable catalyst for extractive-catalytic oxidative desulfurization of model oil

In order to produce ultra-low sulfur fuel, a sandwich-type polyoxometalate (K10[Co4(H2O)2(PW9O34)2]10- (Co4-POM) was covalently immobilized on amino-modified magnetic graphene oxide, and employed as a novel heterogeneous catalyst in an extractive- catalytic oxidative desulfurization system (ECODS). The (Co4-POM@APTES-(Fe3O4/GO)) nanocomposites with various Co4-POM content were prepared. The obtained samples were characterized by XRD, FT-IR, SEM, EDX, N2 adsorption, and VSM techniques. Meanwhile, the effects of Co4-POM load percentage, reaction temperature, catalyst dosage, and H2O2/DBT molar ratio on desulfurization efficiency of the prepared catalyst were investigated. The highest catalytic activity was observed for the sample with 30 wt% Co4-POM content. Dibenzothiophene (DBT) could be completely removed within at 50 ℃ using 4 g catalyst L−1 fuel, and H2O2/DBT molar ratio of 4. In addition, BT and 4,6-DMDBT could be completely removed under the optimized conditions, which suggested a promising prospect of the catalyst for industrial applications. The nanocomposite could be easily separated and reused by utilizing an external magnetic field without any substantial decline in its catalytic activity even after five runs. The kinetic data were fitted to a pseudo-first-order model. Finally, a reaction mechanism for the catalytic oxidation of DBT in the presence of Co4-POM@APTES-(Fe3O4/GO) was proposed.

Cobalt-Based Sandwich-Type Polyoxometalate Supported on Amino-Silane Decorated Magnetic Graphene Oxide: A Beneficial and Recoverable Catalyst for Extractive-Catalytic Oxidative Desulfurization of Model Oil

Cobalt-Based Sandwich-Type Polyoxometalate Supported on Amino-Silane Decorated Magnetic Graphene Oxide: A Beneficial and Recoverable Catalyst for Extractive-Catalytic Oxidative Desulfurization of Model Oil

Molecular characteristics of sulfur compounds in oxidative desulfurization for heavy fuel oil based on APPI FT-ICR MS analysis

Oxidative desulfurization of model oil and heavy fuel oil (HFO) was investigated under mild conditions using H2O2 as an oxidant and acetonitrile as an extractant. The influence factors in the oxidation and extraction processes were evaluated and optimized. The molecular characteristics of the raw feedstock and the desulfurized oils, and the corresponding extraction phases were systematically analyzed by APPI FT-ICR MS, 1H NMR, etc. The results showed that the desulfurization rate of dibenzothiophene reached 97.7% after 10 min reaction, while the sulfur removal efficiency of HFO was 30.7% under optimized conditions. The structures of sulfur compounds were described in heteroatom type, carbon number distribution vs unsaturation degree. The detected main sulfur-containing compounds are S1, S2, S3, NS, OS, O2S, O2S2, and O4S2. Based on the APPI FT-ICR MS results, it can be found that almost all the S1 species have been transformed into sulfone after the oxidation process. Furthermore, the sulfone of O2S1 and O4S2 species in extraction phases were in double bond equivalent (DBE) range from 9 to 25 and carbon number with ≤ 40. 1H NMR results showed that the α to aromatic CH3 combined naphthenic CH-CH2 group accounted for 73.2% in the extraction phase.

Synthesis BiVO4 modified by CuO supported onto bentonite for molecular oxygen photocatalytic oxidative desulfurization of fuel under visible light

A highly photocatalytic activity of bismuth vanadate (BiVO4) modified by CuO was synthesized loaded onto the bentonite (BTT) and applied to photocatalytic oxidative desulfurization of model oil. The photocatalyst was characterized by XRD, SEM, EDS, FT-IR, XPS and UV–vis DRS. The influences of the mass ratio of cata./model oil, the flow rate of molecular oxygen and the irradiation time on the photocatalytic oxidative desulfurization of model oil were investigated by using molecular oxygen as the oxidant. The sulfur removal performances and products of the photocatalytic oxidative desulfurization of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) in model oil under visible light were also discussed. The results showed that the photocatalytic activity of CuO modified BiVO4/BTT for organic sulfur compounds under visible light was significantly higher than that of BiVO4 and BiVO4/BTT. Its oxidative desulfurization reactions for BT, DBT, 4-6DMDBT were the pseudo-first-order reaction, and the desulfurization activity as well as apparent activation energy followed the order of DBT > 4,6-DMDBT > BT. The photocatalytic oxidative desulfurization mechanism of CuO-BiVO4/BTT was analyzed through the calculated band gap, valence band and conduction band position. The recycling experiment presented that DBT removal by CuO-BiVO4/BTT still reached 81.5% after ten cycles.

Hierarchical Ti-Beta zeolites with uniform intracrystalline mesopores hydrothermally synthesized via interzeolite transformation for oxidative desulfurization

Precisely designing and constructing metallosilicate zeolite with abundant and uniform intracrystalline mesopore is urgently desired, bearing the merits of boosting accessibility of active sites and of improving diffusion properties for organics in the process of catalytic reactions. Herein, hierarchical Ti-Beta zeolite with uniform intracrystalline mesopore (ca. 3.4 nm) is hydrothermally synthesized via interzeolite transformation of siliceous FAU zeolite, which is not capable to be achieved using amorphous silica sources. The crystallization process is thoroughly explored via series of characterization methods, obeying liquid crystallization mechanism. Additionally, the assembly of hierarchical Ti-Beta zeolite is nourished by the primary structural units (mainly 4-membered ring) resulting from the degraded silicate species of FAU zeolite. This burgeoning hierarchical Ti-Beta zeolite shows extraordinary catalytic performances in terms of both active site-based turnover frequency and weight-based space-time-yield for oxidative desulfurization of model oil, far beyond than conventional fluoride-mediated Ti-Beta and microporous Ti-Beta prepared by this developed strategy without addition of CTAB, which is attributed to its excellent diffusion properties and undemanding contact of active sites with reaction substrates. This work provides a span-new guidance for designing hierarchical metallosilicates with uniform mesopore from the standpoint of employing exotic primary structural units derived from the degradation of crystallized siliceous zeolites.

Oxidative desulfurization of model oil and oil cuts with MoO3/SBA-15: experimental design and optimization by Box–Behnken method

Using wet impregnation method, MoO3 particles were loaded on hierarchical silica support, SBA-15, and applied for oxidative desulfurization (ODS) process from a model oil containing dibenzothiophene (DBT). The experiments were carried out by the use of H2O2 and acetonitrile as oxidant and extractant. The MoO3/SBA-15 catalyst was characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscope (FE-SEM) and Brunauer–Emmett–Teller (BET) analyses. At first, the effect of molybdenum loading was examined. Then, the effect of operating parameters on ODS including temperature, catalyst dosage, the molar ratio of H2O2/DBT and reaction time were investigated using Box–Behnken experimental design. The complete efficiency, ~ 100% S removal, was achieved by 0.004 g mL−1 catalyst at 55 oC within 49 min reaction time and H2O2/DBT = 9. At the optimized operating conditions, real oil cuts of gasoline and gas oil were tested and the S removal efficiency of 69.73% and 49% was achieved. The desulfurization activity of the catalyst from DBT model oil after 5 times regeneration was above 93%.

Efficient pyridinium-based ionic liquid for deep oxidative desulfurization of model oil

The present research work reports the synthesis of a pyridinium-based ionic liquid (IL) 1-butyl-4-methylpyridinium benzoate [BMPy][(C6H5)COO]. Full characterization of [BMPy][(C6H5)COO] was then performed using 1H NMR, 13C NMR, FTIR, TGA, and elemental analysis. [BMPy][(C6H5)COO] was firstly applied in the extractive desulfurization (EDS) of a model oil consisting of dibenzothiophene (DBT) and dodecane (1000 ppm), where 63.1% DBT-removal efficiency was revealed under optimum conditions of 60 °C, 90 min, and a mass ratio of 1:1 (IL/model oil). To further improve the efficiency of DBT-removal, [BMPy][(C6H5)COO] was subsequently employed in oxidative desulfurization (ODS), where it acted as an extractant with H2O2 as an oxidant. Successfully, 98.9% of DBT was removed at 60 °C and within 90 min using an equal mass ratio of IL/model oil and molar ratio (8) of O/S. Moreover, [BMPy][(C6H5)COO] could be regenerated and recycled for five consecutive runs while retaining approximately the same ODS efficiency. A mechanism of ODS using [BMPy][(C6H5)COO] was proposed. The π–π interactions between IL's structure and DBT were suggested to be the driving force behind the extraction power of [BMPy][(C6H5)COO]. Furthermore, recommendations for future research directions of ODS using ILs were introduced. Finally, a comparison of ODS results for [BMPy][(C6H5)COO] and different pyridinium-based ILs for various model oils was conducted where [BMPy][(C6H5)COO] showed to be a competitive and promising type of pyridinium-based IL for use in the ODS processes.

Oxidative desulfurization of model oil over Ta-Beta zeolite synthesized via structural reconstruction

As to metallosilicate zeolites, ions with larger size such as Ta5+ in the gels greatly retarded their crystallization during the hydrothermal synthesis, affording long-winded synthesis periods, up-limited framework-substituted metal contents, or even frustrated outcome. An efficient hydrothermal synthesis strategy for metallosilicate, in this case of Ta framework-substituted *BEA zeolite, via structural reconstruction was proposed to stride the gap. The Ta content in our developed Ta-Beta-Re-50 zeolite achieved up to 5.48 % (Si/Ta = 52), breaking through the limitation of Ta contents for conventional method (Si/Ta > 100). Additionally, this Ta-Beta-Re zeolite possessed nanosized crystals (20–40 nm) and short crystallization time (8 h), significantly improving space-time yields of practical zeolite production. Through spectroscopic study, it was confirmed that the existence of zeolite structural units intensively facilitated the formation of nucleation and crystal growth. This innovative Ta-Beta zeolite demonstrated high catalytic performances for oxidation desulfurization, far outperforming traditional fluoride-mediated Ta-Beta-F, which was ascribed to its excellent diffusion properties and incredible high isolated Ta contents. Additionally, the catalytic performance of Ta-Beta-Re could be regenerated after simple calcination and the deactivation may be caused by pore blocking of organics. This work provides a new method for rationally design and construction of metallosilicate materials with high activity for catalytic oxidation applications, which can bridge the conceptual and technical gap between periodic trends and zeolite material synthesis.

Ultra‐Deep Oxidative Desulfurization of Model Oil Catalyzed by In Situ Carbon‐Supported Vanadium Oxides Using Cumene Hydroperoxide as Oxidant

Ultra‐Deep Oxidative Desulfurization of Model Oil Catalyzed by In Situ Carbon‐Supported Vanadium Oxides Using Cumene Hydroperoxide as Oxidant

Magnetic WO3/Fe3O4 as catalyst for deep oxidative desulfurization of model oil

In this work, a magnetic WO3/Fe3O4 catalyst was synthesized by grinding-calcination method and applied in the deep oxidative desulfurization of dibenzothiophene (DBT). The results showed that the as-synthesized WO3/Fe3O4 had high catalytic efficiency for sulfur-removal. The content of WO3, amount of the catalyst, TBHP/DBT molar ratio and reaction temperature had significant effects on the desulfurization efficiency. The highest DBT conversion of 92.3% was achieved on 35% WO3/Fe3O4 catalyst with the O/S ratio of 12:1 at 100 °C for 4.5 h. The results of this study revealed that WO3/Fe3O4 catalyst has excellent potential for desulfurization properties because of its high catalytic activity and easy separation ability under an external magnetic field.

HDMF]Cl-based DES as highly efficient extractants and catalysts for oxidative desulfurization of model oil.

N,N-Dimethylformamide hydrochloric acid/XMCln ([HDMF]Cl/XMCln, M = Zn or Fe, n = 2 or 3) was synthesized by stirring the mixture of [HDMF]Cl and metal chloride. [HDMF]Cl-based DES was characterized by FT-IR spectroscopy, ESI-MS and 1H-NMR spectroscopy. The oxidative desulfurization activity was investigated using [HDMF]Cl/0.2FeCl3 and [HDMF]Cl/ZnCl2 as the extractant and catalyst, and hydrogen peroxide (H2O2) as the oxidant. The desulfurization rate can reach up to 98.08% and 99.2% for DBT using [HDMF]Cl/0.2FeCl3 and [HDMF]Cl/ZnCl2, respectively. After recycling for 7 times, the removal rate of DBT still can reach more than 97%.

Direct synthesis of ordered meso/macrostructured phosphotungstic acid/SiO2 by EISA method and its catalytic performance of fuel oil

A series of ordered meso/macrostructured phosphotungstic acid (HPW)/SiO2 materials were synthesized by evaporation-induced self-assembly (EISA) method using nonionic surfactant (P123) and monodispersed polystyrene (PS) spheres as templates. SEM images displayed close-packed ordered macropores with an average pore size of 210nm. TEM, small-angle XRD and N2 adsorption-desorption isotherms confirmed the existence of two-dimensional (2D) hexagonal (p6mm) mesostructure, embedded in the wall of macropores. The wild-angle XRD and FT-IR spectra proved that the Keggin-type HPW were finely dispersed in a silica matrix. The composite materials were used as catalysts for oxidative desulfurization of model oil (ODS). Compared with the ordered meso/macroporous HPW/SiO2 catalyst and ordered macroporous HPW/SiO2 catalyst prepared by colloidal crystal template method, ordered meso/macroporous HPW/SiO2 catalysts synthesized through EISA method displayed much higher catalytic activity of thiophenol, dibenzothiophene (DBT) and its alkyl derivatives, achieving the thiophenol, BT, DBT, 4-MDBT and 4,6-DMDBT conversions of 100%, 83.3%, 99.3%, 89.1% and 86.5% within 40min under the optimum conditions. This feature may be attributed to the larger mesoporous specific surface area and peculiar hierarchically meso/macroporous structural characteristics of the catalyst. Moreover, the catalytic activity has no obviously decreased even after sixth cycle of uses.

Green synthesis of bimetallic Pt@Cu nanostructures for catalytic oxidative desulfurization of model oil

This study reports the synthesis of bimetallic Pt@Cu nanostructures at elevated temperature of 100 °C using Alchornea laxiflora leaf extract (ALLE). The nanostructures have been characterized using UV–vis spectroscopy, high resolution transmission electron microscopy (HRTEM), Fourier Transform Infrared spectroscopy (FTIR), energy dispersive X-ray(EDX) spectroscopy and X-ray diffraction (XRD) techniques. The sizes of the bimetallic Pt@Cu nanostructures range from 1.87 to 2.38 nm with an average particle size of 2.12 ± 0.21 nm, and they crystallized in face-centered cubic (fcc) symmetry. The EDX analysis confirms the bimetallism of Pt@Cu nanostructures and individual metals are present in the ratio 2:3. FTIR indicates strong peaks at 3427 cm−1 which is attributed to hydroxyl group of polyphenolic compounds in ALLE, and the peak disappeared completely in the FTIR of Pt@Cu nanostructures, thus confirming their significant roles in bioreduction process. Catalytic oxidative property of Pt@Cu nanostructures was investigated by oxidation of a model oil [dibenzothiophene (DBT) dissolved in n-heptane] to their corresponding sulfone. Our results show that bimetallic Pt@Cu nanostructures have higher catalytic oxidative activity than the conventional acetic acid that is used in the oxidative desulfurization process. The catalytic oxidative desulfurization activity shown by the Pt@Cu nanostructures promises the potential application in petroleum industry.

Deep-desulfurization of the petroleum diesel using the heterogeneous carboxyl functionalized poly-ionic liquid

Acidic carboxyl functionalized poly(ionic liquid) (CFPIL) has been synthesized and characterized by various techniques like FT-NMR,Fourier transform infrared spectroscopy (FTIR). In this work, deep oxidative desulfurization of model oil (thiophene dissolved in iso-octane) byCFPIL catalyst was carried out in presence of 30 wt% H2O2 solution as an oxidant. The effects of the hydrogen peroxide, amount of CFPIL,temperature-time and recyclability are scrutinized systematically. It was found that the effective molar proportion of H2O2 to sulfur was 4:1 at 70 °Cin 180 min with 0.6 g catalyst, removing 100% thiophene from model oil. This method has shown high efficiency for the removal of thiophene,which is difficult to remove from the oil than benzothiophene and dibenzothiophene. Additionally, an oxidative desulfurization mechanism hasbeen proposed according to the experimental results. This catalytic system by CFPIL offers advantages such as higher efficiency, low amount ofionic liquid, simple work up for separating oil from the catalyst and ease of recycling. This protocol inclines to show that diesel fuels in industrycan be purified to sulfur-free or ultra-low sulfur fuels by further deep oxidative desulfurization with CFPILs after hydrodesulfurization.

Photocatalytic oxidative desulfurization of model oil catalyzed by TiO2 with different crystal structure in the presence of phase transfer catalyst

The photocatalytic oxidative desulfurization is one of the promising processes to realize the deep desulfurization of the fuel. A series of TiO2 nanoparticles (TiO2 NPs) were prepared to investigate the effect of annealing temperatures on its physical properties and the photocatalytic oxidative desulfurization performance. Their physicochemical properties were investigated by X–ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermal gravimetric and differential thermal analysis (TG–DTA), scanning electron microscopy (SEM), and X–ray energy dispersive spectrometer (EDS). The results show that, the crystallite structure of TiO2 NPs annealed at 250–450°C was mainly composed of anatase phase. The rutile phase appeared when the anneal temperature increased to 550°C and all of the anatase converted into rutile phase when annealed at 750°C. The effect of crystallite structure of TiO2 on its photocatalytic oxidative desulfurization performance was investigated using benzothiophene (BT) as the model sulfur compound. The anatase phase was preferable for the photocatalytic oxidation of BT. Phase transfer catalyst plays an important role for improving the photocatalytic desulfurization rate. The photocatalytic oxidative reaction mechanism was also proposed in the presence of TiO2 as catalyst, H2O2 as oxidant, and the DMDAAC as phase transfer catalyst. In the heterogeneous catalytic system, the entire reaction rate is mainly determined by the oxidation reaction and the extraction process, in which the oxidation process could be the rate determining step.

Deep-desulfurization of the petroleum diesel using the heterogeneous carboxyl functionalized poly-ionic liquid

Abstract Acidic carboxyl functionalized poly(ionic liquid) (CFPIL) has been synthesized and characterized by various techniques like FT-NMR, Fourier transform infrared spectroscopy (FTIR). In this work, deep oxidative desulfurization of model oil (thiophene dissolved in iso-octane) by CFPIL catalyst was carried out in presence of 30 wt% H 2 O 2 solution as an oxidant. The effects of the hydrogen peroxide, amount of CFPIL, temperature-time and recyclability are scrutinized systematically. It was found that the effective molar proportion of H 2 O 2 to sulfur was 4:1 at 70 °C in 180 min with 0.6 g catalyst, removing 100% thiophene from model oil. This method has shown high efficiency for the removal of thiophene, which is difficult to remove from the oil than benzothiophene and dibenzothiophene. Additionally, an oxidative desulfurization mechanism has been proposed according to the experimental results. This catalytic system by CFPIL offers advantages such as higher efficiency, low amount of ionic liquid, simple work up for separating oil from the catalyst and ease of recycling. This protocol inclines to show that diesel fuels in industry can be purified to sulfur-free or ultra-low sulfur fuels by further deep oxidative desulfurization with CFPILs after hydrodesulfurization.

Preparation of CoWO4/g-C3N4 and its Ultra-Deep Desulfurization Property

The ultra-deep desulfurization of fuel oil has become inevitable for environmental protection. Here, CoWO4/g-C3N4 was used as a catalyst, H2O2 as an oxidant, and 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4], IL) as an extractant for the oxidative desulfurization of model oil. Scanning electron microscopy, FT-IR spectroscopy, N2 adsorption isotherms, and X-ray diffraction were used to confirm the morphology, structure, and properties of the catalysts. The influence of calcination temperature, loading dose of cobalt, amount of H2O2, reaction temperature, and other parameters were investigated. The removal rate of sulfide in model oil could reach 92.9 % at 80°C in 180 min under the optimal operation conditions (V(oil) = 5 mL, T = 80°C, m(catalyst) = 0.03 g, V(H2O2) = 0.4 mL, t = 180 min, V(IL) = 1.0 mL). In addition, the catalyst was reused five times with no significant reduction in the catalytic activity.