Oxidative Desulfurization of Dibenzothiophene (King Saud University)

As the world’s largest oil producer, Saudi Arabia is keenly interested in desulfurization techniques. Here is an article from King Saud University that landed in my inbox, thanks to a Google® Scholar alert.

///////
Research Article | Open Access
Volume 2020 |Article ID 3894804 | 11 pages | https://doi.org/10.1155/2020/3894804
Ionothermal Synthesis of Metal Oxide-Based Nanocatalysts and Their Application towards the Oxidative Desulfurization of Dibenzothiophene
Bader Alenazi, Ali Alsalme , Saad G. Alshammari, Rais Khan , and Mohammed Rafiq H. Siddiqui
Department of Chemistry, College of Science, King Saud University, Saudi Arabia
Abstract
Herein, different types of metal-containing ionic liquid (IL) complexes and various metal oxide-based nanocatalysts have been successfully prepared (from ionic liquids) and applied for the oxidative desulfurization (ODS) of dibenzothiophene (DBT). The ILs complexes are comprised of N,N′-dialkylimidazolium salts of the type [RMIM-Cl]2[MCln], where [RMIM+] = 1 alkyl-3-methylimidazolium and M = Mn(II)/Fe(II)/Ni(II)/Co(II). These complexes were prepared using an easy synthetic route by refluxing the methanolic solutions of imidazolium chloride and metal chlorides under facile conditions. The as-prepared complexes were further used as precursors during the ionothermal and chemical synthesis of various metal oxide-based nanocatalysts. The resulting ILs salts and metal oxides NPs have been characterized by FT-IR, TGA, XRD, SEM, and TEM analysis. The results indicate that thermal and chemical treatment of ILs based precursor has produced different phases of metal oxide NPs. The calcination produced α-Fe2O3, Mn3O4, and Co3O4, NPs, whereas the chemical treatment of the ILs salts have led to the production of Fe3O4, Mn2O3, and α-Co(OH)2. All the as-prepared salts and metal oxide-based nanocatalysts were used as catalysts towards ODS of dibenzothiophene. The oxidation of dibenzothiophene was performed at atmospheric conditions using hydrogen peroxide as the oxygen donor. Among various catalysts, the thermally obtained metal oxide NPs such as α-Fe2O3, Mn3O4, and Co3O4, have demonstrated relatively superior catalytic activities compared to the other materials. For example, among these nanocatalysts, α-Fe2O3 has exhibited a maximum conversion (∼99%) of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTO2).
1. Introduction
The increasing demand for petroleum products has led to a significant enhancement in the environmental pollution, due to the emission of poisonous gases during combustion [1]. This has led to the formulations of stringent regulations for fuel specifications, which has tremendously increased the demand of deep desulfurization of transportation fuels. Particularly, the presence of sulfur-containing compounds, such as sulfides, disulfides, and thiophenes in transportation fuels, which typically produce SOx, is a major cause of air contamination [2]. To limit the emission of hazardous sulfur compounds, several countries have legislated stringent environmental regulations and strongly promoted the desulfurization of fuels (“S-free” fuels (S content <10 4="" 6="" 8="" active="" activity="" also="" and="" are="" aromatic="" automobiles="" benzothiophene="" besides="" br="" by="" catalysts="" catalytic="" causes="" compounds="" conditions="" contents="" conventional="" converters.="" cost="" damage="" deep="" demand="" desulfurization="" dibenzothiophene="" diesel="" difficult="" dimethyl="" disulfides="" due="" efficiently="" excessive="" fuel="" hds="" high="" highly="" hindrance="" however="" hydrodesulfurization="" in="" including="" increase="" irreversible="" is="" large="" leading="" lifetime="" like="" metal="" of="" performed="" ppm="" presence="" present="" pressure="" process="" proportion="" reduction="" remove="" removed="" removes="" require="" several="" significant="" steric="" sulfides="" sulfur="" technique="" temperature="" the="" their="" these="" thiols="" to="" typically="" under="" used="" using="" usually="" various="" which=""> To overcome this, several deep desulfurization techniques have been developed, including extraction, oxidation, photooxidation, bioprocess, adsorption, and extraction by ionic liquids [10–12]. Among these techniques, oxidative desulfurization (ODS) effectively removes the aromatic sulfur compounds from fuels under mild condition and thus has gained significant prominence [13]. During the ODS, sulfur compounds are converted into their corresponding sulfones which are generally extracted using polar solvents. So far, several oxidants have been used during this process, such as, hydrogen peroxide (H2O2), organic peroxides, molecular oxygen, and ozone [12, 14]. Out of these oxidants, H2O2 has been found to be more effective and produces only water as a side product [15]. The ODS can be performed by several methods which include solvent extraction, photocatalytic oxidation, microwave catalytic oxidation, and so on [16–18]. Apart from this, several other methods are being intensively studied to improve the current HDS technology by developing more effective catalysts and other materials used in this process [19].
In this regard, ionic liquid- (IL-) assisted ODS has also been used extensively due to the high efficiency of IL in the removal of sulfur compounds [20]. So far, ILs have demonstrated great potential in ODS due to their remarkable properties such as, good thermal stability, extremely low volatility, enhanced solubility, excellent ionic conductivity, and wide liquid temperature range [21]. Moreover, they can be used effectively both as catalysts and extractants (solvents) to replace volatile organic compounds which are flammable, hazardous, and are threat to the environment [22, 23]. Currently, the process of catalytic ODS, in which ILs are applied as both homogeneous and/or heterogeneous catalysts have received greater attention when compared to the extraction of sulfur compounds with ILs [24]. Particularly, the trend of applying supported ILs as heterogeneous catalysts has become more popular, as being a solid catalyst it can offer greater advantage. For instance, IL-based solid catalysts demonstrate superior chemical properties such as, increased active sites and enhanced dispersion, and they are also easy to separate from the reaction mixture [25].
Recently, in several studies, metallic or metal oxide nanoparticles (NPs) together with ILs have been applied either as support or active catalyst for the catalytic conversion of sulfur compounds [26]. These IL-based nanocatalysts exhibit both homogeneous and heterogeneous catalytic properties, which not only facilitate rapid and selective chemical transformations but also offer enhanced yield and easy separation and recovery of catalysts [27]. In several studies, ILs have demonstrated excellent potential for the synthesis of various inorganic metal and metal oxide NPs [28]. Particularly, the thermal synthesis of nanomaterials using ILs (ionothermal synthesis) has received considerable attention of researchers. However, the ionothermal synthesis of metallic or metal oxide NPs has been rarely studied. In our previous study, we have demonstrated the ionothermal synthesis of NiO NPs using N,N′-dialkylimidazolium salts of the type [RMIM-Cl]2[MCln], where [RMIM+] = 1-alkyl-3- methylimidazolium and M = Ni(II) ionic liquid [29]. The as-prepared IL was used a precursor, which was calcined at 500°C for several hours to produce Ni NPs. The study has revealed the significant effect of IL on the shape and morphology of resultant NPs Scheme 1.
For further continuation of our previous work, in this study, we demonstrate the preparation of transition metal-containing IL-based complexes. The as-prepared complexes were used as precursors for the synthesis of different metal oxide NPs including Manganese (Mn), Iron (Fe), Cobalt (Co), and Nickel (Ni) NPs using thermal and chemical treatment methods. The IL-based precursors are made up imidazolium and N,N′-dialkylimidazolium salts of the type [RMIM-Cl]2[MCln], where [RMIM+] = 1-alkyl-3-methylimidazolium and M = Mn(II), Fe(II), Ni(II), and Co(II). The resultant complexes and metal oxide NPs have been characterized by powder X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Both the IL-based precursors and resultant NPs have been tested for their catalytic activity towards the oxidative desulfurization of dibenzothiophene (DBT).
Free full text source: https://www.hindawi.com/journals/jchem/2020/3894804/
///////

According to Wikipedia, King Saud University (https://ksu.edu.sa/en/ ) is a public university in Riyadh, Saudi Arabia, founded in 1957 by King Saud bin Abdulaziz as Riyadh University, as the first university in the Kingdom of Saudi Arabia. The university was created to meet the shortage of skilled workers in Saudi Arabia. It was renamed King Saud University in 1982.
///////

TIP: Google® King Saud University Bader Alenazi, one of the authors of the article highlighted above. Do the same search with the other authors.

Here are some results …

///////
Bader Alenazi
Ali Alsalme
  King Saud University, Chemistry, Post-Doc
Catalysts
Kingdom of Saudi Arabia
Papers
α-Pinene isomerisation over heteropoly acid catalysts in the gas-phase
Applied Catalysis A-general, 2010
Solid acid catalysts based on H 3PW 12O 40 heteropoly acid: Acid and catalytic properties at a gas–solid interface
Journal of Catalysis, 2010
Solid acid catalysts prepared by supporting 15 wt%H3PW12O40 heteropoly acid (HPA) on TiO2, ZrO2 a... more
Heteropoly acids as catalysts for liquid-phase esterification and transesterification
Applied Catalysis A-general, 2008
Esterification of hexanoic acid and transesterification of ethyl propanoate and ethyl hexanoate w... more
source: http://king-saud.academia.edu/AliAlsalme

Saad G. Alshammari
Saad G. Alshammari's research while affiliated with King Saud University and other places
Publications (4)
Scheme 1: Schematic representation of the preparation of...
Ionothermal Synthesis of Metal Oxide-Based Nanocatalysts and Their Application towards the Oxidative Desulfurization of Dibenzothiophene
Article
Mar 2020

Bader Alenazi
Ali Alsalme
Saad G. Alshammari[...]
M R H Siddiqui
Herein, different types of metal-containing ionic liquid (IL) complexes and various metal oxide-based nanocatalysts have been successfully prepared (from ionic liquids) and applied for the oxidative desulfurization (ODS) of dibenzothiophene (DBT). The ILs complexes are comprised of N,N′-dialkylimidazolium salts of the type [RMIM-Cl]2[MCln], where [...

///////

Google® Better!
Jean Steinhardt served as Librarian, Aramco Services, Engineering Division, for 13 years. He now heads Jean Steinhardt Consulting LLC, producing the same high quality research that he performed for Aramco.

Follow Jean’s blog at: http://desulf.blogspot.com/  for continuing tips on effective online research
Email Jean at research@jeansteinhardtconsulting.com  with questions on research, training, or anything else
Visit Jean’s Web site at http://www.jeansteinhardtconsulting.com/  to see examples of the services we can provide

Hybridized and Catalyzed: nanohybrid catalyst for oxidative desulfurization of dibenzothiophene

I found the following article, thanks to a Google® Scholar alert I set up a couple of years ago. The abstract makes the article look interesting in itself. The abstract also suggests keywords for further Googling.

Here is the abstract …

///////
A new simple protocol for the synthesis of nanohybrid catalyst for oxidative desulfurization of dibenzothiophene
Environmental Science and Pollution Research (2019)
Published: 11 December 2019
Mahboube Ghahramaninezhad & Ali Ahmadpour
Author information
Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box 91779-48944, Mashhad, Iran.
ahmadpour@um.ac.ir
Abstract
This study offers an investigation of the catalytic activity of TiO2/SiO2 during oxidative desulfurization (ODS) of a model fuel that includes dibenzothiophene (DBT), using hydrogen peroxide (H2O2) as a green oxidant in the absence of UV irradiation. For the first time, though a novel and simple protocol, TiO2/SiO2 nanohybrid was synthesized using ascorbic acid and glycerol as green complexing and polymerizing agents, respectively. The TiO2/SiO2 catalyst was thoroughly characterized by XRD, FT-IR, nitrogen adsorption-desorption measurements, TEM, FESEM, and TGA. Results revealed a high catalytic oxidative activity for the catalyst in the removal of DBT regarding sulfur removal up to 99.4% within 20 min under optimum reaction conditions. The main factors affecting the ODS process, including catalyst dosage, temperature, O/S molar ratio, and different oxidizing agents, were evaluated to identify optimum conditions. The desulfurization efficiency of the recoverable catalysts showed no loss in activity after four times. The present article suggests a new and green method for the synthesis and characterization of an efficient catalyst (TiO2/SiO2) in deep oxidative desulfurization at 25 °C and removal of refractory organosulfur compounds that yield ultra-low sulfur fuels. Also, it proved to have a much higher catalytic oxidation capacity when compared to pure TiO2.
source: https://link.springer.com/article/10.1007/s11356-019-07048-z
///////

TIP: Squeeze a little bit more juice out of this abstract. Google®: oxidative desulfurization nanohybrid

One result is an open access article, meaning you can read the full text without charge …

///////
[ EXCERPTS ]
A Comprehensive Review on Catalytic Oxidative Desulfurization of Liquid Fuel Oil
Article (PDF Available) in Catalysts · March 2019 with 190 Reads 
DOI: 10.3390/catal9030229
Muhammad Nobi Hossain & Hoon Chae Park
Yonsei University
Abstract
The production of green fuel oil is of the utmost importance for maintaining a healthy life and environment in the current world. Effective and complete removal of sulfur refractory compounds (such as 4,6-dimethyldibenzothiophene and other alkyl-substituted thiophene derivatives) from fuel oil is essential to meet the new requirements of sulfur standards. Several techniques have been proposed for desulfurization of fuel oil, such as hydrodesulfurization (HDS), selective adsorption, extractive distillation, biodesulfurization, and oxidative desulfurization (ODS).The removal of sulfur by the HDS process requires higher investment costs, high reaction temperature (up to 400 ◦C), and high pressure (up to 100 atm) reactors. On the other hand, studies have shown that the ODS process is remarkably successful in the removal of sulfur under mild reaction conditions. This review article presents a comparative analysis of various existing catalytic oxidation techniques:acetic acid/formic acid catalytic oxidation, heteropolyacid (HPA) catalytic oxidation, ionic liquid catalytic oxidation, molecular sieve catalytic oxidation, polyoxometalates catalytic oxidation, titanium catalytic oxidation, and ultrasound-assisted oxidation systems, as well as discusses research gaps,and proposes important recommendations for future challenges.

Conclusions, Future Challenges, and Recommendations
Hydrodesulfurization is a well-established and conventional technique used in oil refinery industries. However, it involves certain constraints, such as higher investment costs. In order to meet the new standards specified for sulfur, the HDS process needs to perform under high reaction conditions, such as high temperature (~400 C), high pressure (~100 atm), and in a large reaction vessel, which raises the amount of investment costs. Therefore, newer techniques, such as extractive desulfurization, biodesulfurization, extraction with ionic liquids, selective adsorption, and oxidative desulfurization have been proposed in addition, or as alternatives, to HDS. Amongst these alternative methods, the oxidative desulfurization process has received more attention due to its mild operating condition and high sulfur removal efficiency. However, there still exists many issues with the ODS process, such as high loading of the oxidizing agent, deactivation of the catalyst, increasing investment costs with increasing sulfur concentration in the feedstock, and waste management of the oxidized sulfur compounds. Several initiatives have been proposed to address these drawbacks found in the ODS method, which include developing a cost effective, high efficiency, and recyclable catalyst, and developing an environment friendly and cheap oxidizing agent. Eventually, to meet the revised sulfur standards recommended by USEPA and the public demand for safer fuels, effective catalytic oxidative desulfurization of fuel oil is required by improvising the ODS process with technological innovations. Until now, the hydrotreating activity of different oxidative catalysts is limited to model sulfur compounds with short chains. On the contrary, the catalyst’s activity in the case of real feedstock with heavy sulfur compounds would vary from the model feedstock, which has not yet been studied in-depth. Therefore, another challenge that remains for researchers is to examine the application of the catalyst in the oxidative desulfurization of real feedstock of heavy oil, such as waste tire pyrolysis oil. Besides these challenges, the more critical challenge is the commercialization of the catalytic oxidative desulfurization process due to some major obstacles, such as low selectivity for the sulfides present in fuel feedstock, recovery, and separation of the used catalysts after the reaction.  
Free full text source: https://www.researchgate.net/publication/331486586_A_Comprehensive_Review_on_Catalytic_Oxidative_Desulfurization_of_Liquid_Fuel_Oil
///////

Google® Better!
Jean Steinhardt served as Librarian, Aramco Services, Engineering Division, for 13 years. He now heads Jean Steinhardt Consulting LLC, producing the same high quality research that he performed for Aramco.

Follow Jean’s blog at: http://desulf.blogspot.com/  for continuing tips on effective online research
Email Jean at research@jeansteinhardtconsulting.com  with questions on research, training, or anything else
Visit Jean’s Web site at http://www.jeansteinhardtconsulting.com/  to see examples of the services we can provide

Get a Room: Oxidative Desulfurization Of Dibenzothiophene At Room Temperature

On the NASA scale of technology readiness, the following article probably would be ranked “1.” Still, whether you are engaged in basic research or are more interested in practical solutions you can implement today, it is nice to be aware of what may be coming down the pike.

///////
Comptes Rendus Chimie
Available online 14 December 2018
In Press, Corrected Proof
Efficient catalytic performance of tetra-alkyl orthotitanates for the oxidative desulfurization of dibenzothiophene at room temperature
Xiaolin Li a, Hui Qi b, Wei Zhou c, Wei Xu d, Yinyong Sun a
aMIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
bThe Second Hospital of Jilin University, Changchun 130041, China
cKey Laboratory of Functional Inorganic Material Chemistry, Heilongjiang University, Ministry of Education, Harbin 150080, China
dState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China
Abstract
Desulfurization of fuel oil is of great importance for producing clean energy. In this study, we report that tetra-alkyl orthotitanates exhibited efficient catalytic performance in the oxidative desulfurization of dibenzothiophene. The sulfur content in model oil (1000 ppmw) could be reduced to less than 10 ppmw within 10 min at room temperature and ambient pressure. In addition, the formed sulfones can be easily separated from the oil phase without extraction process. This work will provide a basis for the design of novel oxidative desulfurization catalysts with high desulfurization efficiency.
source: https://www.sciencedirect.com/science/article/pii/S1631074818302753
///////