Catalytic Conversion of Benzothiophene Over a H-ZSM5 Catalyst, Reactivity and a Kinetic Model

Nowadays and due to environmental legislations, a world-wide attention has been given towards clean transportation fuels with emphasis on sulfur contents reduction. These efforts on the other hand are challenged by the poor qualities of crude oils. The existing desulfurization technologies such as hydrodesulfurization are not capable to cope with new firm standards. Hence, it is extremely desirable to develop a catalytic desulfurization process to meet both sulfur limits and refining economics. As one aspect of this objective, it is of great importance to study and comprehend the behaviour and chemistry of individual sulfur species present in transportation fuels cuts. Zeolites namely, H-ZSM5 has shown a potential catalyst for a desulfurization process for gasoline fuel range. Acidity and shape selectivity of these zeolites make it viable for such a process eliminating the use of hydrogen. With aiming to light diesel fraction desulfurization, this dissertation provides insights and understanding of benzothiophene sulfur species conversion over a H-ZSM5 zeolite catalyst. The H-ZSM5 particles were dispersed in an inert silica-alumina matrix to diminish possible cracking of diesel model compound (n-dodecane). This catalyst was characterized using standard techniques including: a) NH3-TPD, b) N2 adsorption, c) Particle size distribution, d) X-ray diffraction, e) SEM-EDX, and f) Pyridine FTIR. Catalytic and thermal runs were performed in the CREC Riser Simulator that mimics the industrial FCC unit. This reaction system was operated at close to atmospheric pressure, 350°C – 450°C temperatures, and 3, 5, 7 seconds reaction times. Thermal cracking was found to be negligible under the studied reaction conditions. Experimental results from catalytic runs showed a higher benzothiophene conversion over n-dodecane conversion. This was true despite the difference in benzothiophene and n-dodecane molecular sizes. The experimental results of this PhD dissertation are also supported with a molecular dynamics (MD) simulation study that studies self diffusivity of benzothiophene and n-dodecane in ZSM-5 zeolite. In addition and using the obtained experimental data, a heterogeneous kinetic model is proposed for benzothiophene conversion over H-ZSM5 catalyst. Numerical non-linear regression leads to model parameters estimations with low confidence intervals suggesting the adequacy of this kinetic model

Crude oil to chemicals: light olefins from crude oil

[EN] The possibility to fulfill the increasing market demand and producers' needs in processing crude oil, a cheap and universally available feedstock, to produce petrochemicals appears to be a very attractive strategy. Indeed, many petrochemicals are produced as side streams during crude oil refining, which primary goal remains transportation fuel production. Availability of some critical feedstocks may then depend on local refining policy. In order to improve flexibility, it has been proposed to directly crack crude oil to produce petrochemicals, in particular light olefins (ethylene, propylene, butenes), using technologies derived from fluid catalytic cracking. This paper attempts to review the main research works done on the topic in the literature in the last five decades, focussing on process as well as catalyst technology, with a special interest for fluid catalytic cracking (FCC) based technology that can be used towards maximizing chemicals from crude oil. Factors investigated include use of severe cracking conditions, on-purpose additives (from ZSM5 to more exotic, metal doped additives), recycle streams and multiple riser systems.The authors thank Saudi Aramco for material and financial support. Financial support by the Spanish Government-MINECO through program "Severo Ochoa" (SEV 2012-0267), Consolider Ingenio (2010-Multicat, CSD-2009-0050), MAT2012-31657, CTQ2015-70126-R (MINECO/FEDER), by the European Union through ERC-AdG-2014-671093-SynCatMatch and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is also acknowledged.Corma Canós, A.; Corresa Mateu, E.; Mathieu ., Y.; Sauvanaud ., LL.; Al-Bogami, S.; Al-Ghrami, M.; Bourane, A. (2017). Crude oil to chemicals: light olefins from crude oil. Catalysis Science & Technology. 7(1):12-46. https://doi.org/10.1039/c6cy01886fS12467

Direct crude oil cracking for producing chemicals: Thermal cracking modeling

[EN] The direct cracking of crude oil is an interesting option for producing cheaply large amounts of petrochemicals. This may be carried out with catalyst and equipment similar to that of catalytic cracking, but at a temperature range between that of standard catalytic cracking and steam cracking. Thermal cracking will play a role in the conversion, but is rarely disclosed in experimental or modeling work. Thus, a crude oil and its fractions were thermally cracked and the products yields were modeled using a 9 lumps cracking scheme. It was found that heavy fraction cracks twice as fast as diesel fraction and ten times faster than gasoline fraction, with activation energies in the 140-200 kJ/mol range. Selectivity to ethylene, propylene and butenes were found similar in the operating range explored.The authors thank Saudi Aramco for its material and financial support. Financial support by the Spanish Government-MINECO through programs "Severo Ochoa" (SEV 2012-0267) and CTQ2015-70126-R and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is also acknowledged.Corma Canós, A.; Sauvanaud, LL.; Mathieu, Y.; Al-Bogami, S.; Bourane, A.; Al-Ghrami, M. (2018). Direct crude oil cracking for producing chemicals: Thermal cracking modeling. Fuel. 211:726-736. https://doi.org/10.1016/j.fuel.2017.09.099S72673621

Self Diffusivity of n-Dodecane and Benzothiophene in ZSM-5 Zeolites: Its Significance for a New Catalytic Light Diesel Desulfurization Process

This study provides theoretical support to a recent promising ZSM5 catalyst used for the selective desulfurization of light diesel type compounds (Al-Bogami and de Lasa 2013; Al-Bogami, Moreira, and de Lasa 2013). With this end, Molecular Dynamics (MD) simulations employing a rigid silicalite structure are developed to calculate self-diffusivities of n-Dodecane (n-C12) and Benzothiophene (BZT) in a silicalite structure. The simulations are performed at 573 K, 623 K, 673 K and 723 K at a fixed loading of 1 molecule per unit cell to study the temperature effect on diffusivity coefficient. In addition, a number of simulations which are developed to investigate four molecule loadings (corresponding to 0.25, 0.5, 0.75 and 1 molecule per zeolite unit cell) at 723 K. MD simulations, show a self diffusivity of BZT one order of magnitude higher than that of n-C12 self diffusivity at all temperatures investigated. This is the case in spite of BZT having a critical molecular diameter of 6 Å when compared to the 4.9 Å diameter of n-C12. In addition, the self diffusivity coefficient is found to increase with temperature for both n-C12 and BZT. Furthermore, the results obtained show that the self diffusivity of n-C12 decreases as the number of n-C12 molecules per zeolite unit cell increases. On the other hand, it is observed that the self-diffusivity coefficient for BZT remains fairly constant and drops at a loading of 1 molecule per zeolite unit cell only. These coefficients show that differences in n-C12 and benzothiophene diffusivities favours desulfurization with selective benzothiophene adsorption and sulfur species removal as coke (Al-Bogami and de Lasa 2013).Fil: Ferreira, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Al Bogami, Saad A.. Saudi Aramco Oil Company; Arabia SauditaFil: de Lasa, Hugo. Western University; Canad

Cyclization of Hydrazones of 2-Acetyl-1-naphthol and 1-Acetyl- 2-naphthol with Triphosgene. Synthesis of Spiro Naphthoxazine

molecule

Cellular apoptosis and cell cycle arrest as potential therapeutic targets for eugenol derivatives in Candida auris

Candida auris, the youngest Candida species, is known to cause candidiasis and candidemia in humans and has been related to several hospital outbreaks. Moreover, Candida auris infections are largely resistant to the antifungal drugs currently in clinical use, necessitating the development of novel medications and approaches to treat such infections. Following up on our previous studies that demonstrated eugenol tosylate congeners (ETCs) to have antifungal activity, several ETCs (C1-C6) were synthesized to find a lead molecule with the requisite antifungal activity against C. auris. Preliminary tests, including broth microdilution and the MUSE cell viability assay, identified C5 as the most active derivative, with a MIC value of 0.98 g/mL against all strains tested. Cell count and viability assays further validated the fungicidal activity of C5. Apoptotic indicators, such as phosphatidylserine externalization, DNA fragmentation, mitochondrial depolarization, decreased cytochrome c and oxidase activity and cell death confirmed that C5 caused apoptosis in C. auris isolates. The low cytotoxicity of C5 further confirmed the safety of using this derivative in future studies. To support the conclusions drawn in this investigation, additional in vivo experiments demonstrating the antifungal activity of this lead compound in animal models will be needed

Hemolytic activity of C-5.

Hemolysis of horse red blood cells was done in presence of Triton-X (control) and different concentrations of C-5.</p

Minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) of eugenol tosylate congeners (C1-C6) against different <i>C</i>. <i>auris</i> isolates.

Minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) of eugenol tosylate congeners (C1-C6) against different C. auris isolates.</p

Probing the antibacterial and anticancer potential of tryptamine based mixed ligand Schiff base Ruthenium(III) complexes

Development of new chemotherapeutic agents to treat microbial infections and recurrent cancers is of pivotal importance. Metal based drugs particularly ruthenium complexes have the uniqueness and desired properties that make them suitable candidates for the search of potential chemotherapeutic agents. In this study, two mixed ligand Ru(III) complexes Ru(Cl)(2)(SB)(Phen] (RC-1) and Ru(Cl)(2)(SB)(Bipy)] (RC-2) were synthesised and characterized by elemental analysis, IR, UV-Vis, H-1, C-13 NMR spectroscopic techniques and their molecular structure was confirmed by X-ray crystallography. Antibacterial activity evaluation against two Gram-positive (S. pneumonia and E. faecalis) and four Gram-negative strains (P. aurogenosa, K. pneumoniae, S. enterica, and E. coli) revealed their moderate antibacterial activity with MIC value of >= 250 mu g/mL. Anticancer activity evaluation against a non-small lung cancer cell line (H1299) revealed the tremendous anticancer activity of these complexes which was further validated by DNA binding and docking results. DNA binding profile of the complexes studied by UV-Visible and fluorescence spectroscopy showed an intercalative binding mode with CT-DNA and an intrinsic binding constant in the range of 3.481-1.015 x 10(5) M-1. Both the complexes were also found to exert weak toxicity to human erythrocytes by haemolytic assay compared to cisplatin. Potential of these complexes as anticancer agents will be further delineated by in vivo studies