scholarly journals Assessment of the Oxidative Desulfurization of Middle Distillate Surrogate Fuels with Spectroscopic Techniques

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Eleni Syntyhaki ◽  
Anastasia Detsi ◽  
Dimitrios Karonis
Keyword(s):  
Oxidative Desulfurization ◽  
Ultrasound Irradiation ◽  
Sulfur Compounds ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Surrogate Fuels ◽  
Ft Ir ◽  
Middle Distillates ◽  
Mild Temperature ◽  
Selection Of

The oxidative desulfurization of five (5) model sulfur compounds and eleven (11) surrogate blends was investigated using the hydrogen peroxide (H2O2)-acetic acid (CH3COOH) system. Consequently, extractive desulfurization was carried out using conventional solvents. The model sulfur compounds, as well as the solvent, are present in petroleum middle distillates. The selection of the compounds was made so that they represent various kinds of sulfur compounds. The goal of this study was the implementation of a simple and economical oxidative and extractive system for the desulfurization of surrogate mixtures with an intermediate sulfur concentration 1% w/w, at the mild temperature of 70°C, and without the use of supplementary and assisting methods such as heterogeneous catalysis or ultrasound irradiation. The sulfur content was estimated using X-ray fluorescence. The progress of the oxidation reaction was monitored using liquid FT-IR. The solid sediments of the oxidation procedure were identified with solid-state FT-IR and 1H NMR spectroscopy.

Synthesis, Characterization and X-Ray Crystal Structure of the New Schiff Base and Anticandidal Evaluation

2019 ◽  
Vol 41 (6) ◽  
pp. 1090-1090
Author(s):  
Mehmet Poyraz Mehmet Poyraz ◽  
Musa Sari Musa Sari ◽  
Halil Berber Halil Berber ◽  
Nursenem Karaca and Fatih Demirci Nursenem Karaca and Fatih Demirci
Keyword(s):  
Schiff Base ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Ft Ir ◽  
Anticandidal Activity ◽  
Crystal Structural

A new Schiff base, namely 2-methoxy-6-((2-(4 nitrophenyl) hydrazineylidene) methyl)phenol was synthesized and characterized by melting points, elemental analysis, thermogravimetric analysis and spectroscopic techniques (FT-IR, 1H-NMR and UV-VIS spectra). The chemical structure of compound was further confirmed by single crystal structural X-ray diffraction. The Schiff base is crystallized in the triclinic space group P-1. In the crystal, molecules are linked by O-H…O hydrogen bonds between the hydroxy “-O-” atom and the methoxy “-O-” atom. Furthermore, the synthesized Schiff base was tested for the in vitro anticandidal activities using CLSI broth microdilution method against human pathogenic Candida albicans, C. parapsilosis and C. krusei standard strains. In the anticandidal activity test results, the new Schiff base was found to be effective at 1 mg/mL - 0.25 mg/mL concentrations. (The last line omitted) (The sentence marked in red will be deleted)

scholarly journals Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Electrically Conductive ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ft Ir

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

scholarly journals Hydrogen-Assisted Thermocatalysis over Titanium Nanotube for Oxidative Desulfurization

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Weiwei Tang ◽  
Yue Yao ◽  
Xiaoqiao Huang
Keyword(s):  
Diffuse Reflectance ◽  
Oxidative Desulfurization ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Diffuse Reflectance Spectra ◽  
Ft Ir ◽  
Catalyst Dosage

Titanium nanotubes were hydrothermally synthesized via a two-step method for ODS (oxidative desulfurization). The catalysts’ structures were characterized by XRD (X-ray diffraction), FT-IR, UV-Vis (UV-Vis diffuse reflectance spectra), NH3-TPD, etc. The effects of O/S molar ratio and catalyst dosage, etc., were systematically investigated. The catalyst exhibited remarkable performance, so that the removal of DBT (dibenzothiophene) was nearly 100% under the optimal conditions in 10 min. Also, the catalysts could be easily reused for six consecutive cycles. The hydrogen-assisted thermocatalytic mechanism over titanium nanotubes for ODS was also studied and an effective reactant concentration (ERC) number of 70.8 was calculated.

scholarly journals Conjugation of Penicillin-G with Silver(I) Ions Expands Its Antimicrobial Activity against Gram Negative Bacteria

Antibiotics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 25 ◽  
Author(s):  
Ioannis Ketikidis ◽  
Christina N. Banti ◽  
Nikolaos Kourkoumelis ◽  
Constantinos G. Tsiafoulis ◽  
Christina Papachristodoulou ◽  
...  
Keyword(s):  
Antimicrobial Activities ◽  
Attenuated Total Reflection ◽  
Penicillin G ◽  
Therapeutic Window ◽  
Spectroscopic Techniques ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray ◽  
Ft Ir

Conjugation of penicillin G (PenH) with silver(I) ions forms a new CoMeD (conjugate of metal with a drug) with formula [Ag(pen)(CH3OH)]2 (PenAg). PenAg was characterized by a plethora of physical and spectroscopic techniques, which include in the solid state m.p.; elemental analysis; X-ray fluorescence (XRF) spectroscopy; scanning electron microscopy (SEM); energy-dispersive X-ray spectroscopy (EDX); FT-IR; and in solution: attenuated total reflection spectroscopy (FT-IR-ATR), UV–Vis, 1H NMR, and atomic absorption (AA). The structure of PenAg was determined by NMR spectroscopy. Silver(I) ions coordinate to the carboxylic group of PenH, while secondary intra-molecular interactions are developed through (i) the nitrogen atom of the amide group in MeOD-d4 or (ii) the sulfur atom in the thietane ring in deuterated dimethyl sulfoxide DMSO-d6. The antibacterial activities of PenAg and the sodium salt of penicillin (PenNa) (the formulation which is clinically used) against Gram positive (Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus)) and Gram negative (Pseudomonas aeruginosa (P. aeuroginosa PAO1)) bacteria were evaluated by the means of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and inhibition zone (IZ). PenAg inhibits the growth of the Gram negative bacterial strain P. aeuroginosa with a MIC value of 23.00 ± 2.29 μM, in contrast to PenNa, which shows no such activity (>2 mM). The corresponding antimicrobial activities of PenAg against the Gram positive bacteria S. epidermidis and S. aureus are even better than those of PenNa. Moreover, PenAg exhibits no in vivo toxicity against Artemia salina at concentration up to 300 μΜ. The wide therapeutic window and the low toxicity, make PenAg a possible candidate for the development of a new antibiotic.

Molecular and X-ray Spectroscopies for Noninvasive Characterization of Mayan Green Stones from Bonampak, Chiapas

2019 ◽  
Vol 73 (9) ◽  
pp. 1074-1086
Author(s):  
Valentina Aguilar-Melo ◽  
Alejandro Mitrani ◽  
Edgar Casanova-Gonzalez ◽  
Mayra D. Manrique-Ortega ◽  
Griselda Pérez-Ireta ◽  
...  
Keyword(s):  
Archaeological Site ◽  
Molecular Techniques ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Noninvasive Characterization ◽  
A Minor

A burial and a rich offering were found under Room 2 in the Murals Building, Bonampak, a Mayan archaeological site situated in Chiapas, Mexico. This burial may be related with the creation of the famous mural paintings. A rich set of jewelry made of green stones was among the different objects found. Green stones have great importance in Mesoamerican cultures, those composed of jadeite being the most appreciated. To characterize the green stones, different spectroscopic techniques were used in a complementary way: Raman and infrared spectroscopies (FT-IR) were used for global mineralogical analysis, while X-ray diffraction (XRD) and X-ray fluorescence (XRF) were applied simultaneously in situ on the artifacts that were not successfully identified by these molecular techniques. In addition, XRF was used to contrasts the elemental information from pieces composed of pyroxenes that may be related to the raw sources of jade in Guatemala. The main minerals identified within the beads and earrings were jadeite with omphacite and jadeite with albite; to a minor extent, quartz, and serpentine. In this paper, the main features of the molecular and X-ray techniques are compared in order to determine the advantages and limitations of these spectroscopies for mineral identification. With this combination of techniques, it was possible to undertake a suitable characterization of the analyzed objects. This paper focuses on the XRD–XRF combined analysis for in situ noninvasive characterization.

Syntheses and crystal structures of new aurate salts of adenine or guanine nucleobases

2020 ◽  
Vol 76 (2) ◽  
pp. 139-147
Author(s):  
Anton Savchenkov ◽  
Ludmila Demina ◽  
Alexey Safonov ◽  
Mikhail Grigoriev ◽  
Roman Solovov ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Noncovalent Interactions ◽  
Spectroscopic Techniques ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Nitrogenous Base ◽  
Ir Spectroscopic ◽  
Chloride Monohydrate

Two new gold(III) complexes with adenine or guanine nitrogenous bases as counter-cations were synthesized. These are 6-amino-7H-purine-1,9-diium tetrachloridogold(III) chloride monohydrate, (C5H7N5)[AuCl4]Cl·H2O, 1, and 2-amino-6-oxo-6,7-dihydro-1H-purin-9-ium tetrachloridogold(III) hemihydrate, (C5H6N5O)[AuCl4]·0.5H2O, 2. Their crystal structures were studied using single-crystal X-ray diffraction and FT–IR spectroscopic techniques. The arrangement of species in the studied crystal structures implies π-stacking interactions, as well as concomitant C—H...π interactions, hydrogen bonds and other types of noncovalent interactions, which were studied qualitatively and quantitatively using the method of molecular Voronoi–Dirichlet polyhedra. The variation of the nitrogenous base from adenine to guanine results in evident differences in the packing of the species in the crystals of 1 and 2. The splitting and shifting of bands in the FT–IR spectra of the title compounds reveals several features representative of noncovalent interactions in their crystal structures.

Synthesis, X-ray characterization and catalytic homogenous alcohol oxidation activity of Co(II)–carboxamide complex with green oxidant (H2O2) under mild conditions

2020 ◽  
Vol 235 (6-7) ◽  
pp. 237-244
Author(s):  
Hakan Ünver
Keyword(s):  
Distorted Octahedral Geometry ◽  
Dimethyl Formamide ◽  
Spectroscopic Techniques ◽  
Oxidation Activity ◽  
X Ray ◽  
H Nmr ◽  
Mild Conditions ◽  
Counter Ions ◽  
Ft Ir ◽  
Homogenous Catalyst

AbstractIn this study, a new air and moisture stable mononuclear cobalt(II)–carboxamide complex, [Co(TCrbx)2(CH3OH)2](ClO4)2, was synthesized and characterized (TCrbx = N-(4-methylpyridin-2-yl)thiophene-2-carboxamide). Complex characterization mainly was done with single crystal X-ray analysis. Ligand characterization was done with several spectroscopic techniques (Elemental Analysis, FT-IR, 1H NMR, 13C NMR). Cobalt(II) complex possesses distorted octahedral geometry coordinated with two carboxamide ligands at equatorial and two methanol ligands at axial positions and two perchlorate anions as counter ions. Synthesized complex was successfully tested as homogenous catalyst for the oxidation of benzyl alcohol with environmental friendly oxidant hydrogen peroxide (H2O2) under mild conditions. Benzaldehyde was selectively obtained with the conversion value of 99.5% in dimethyl formamide after 3-h reaction time at 50 °C with 133 TON value. Solvent and temperature effects were also investigated.

scholarly journals Synthesis, Crystal Structures, Hirshfeld Surfaces Analysis and Physico-Chemical Characterization of Two New ZnII and CdII Halidometallates

2021 ◽  
Author(s):  
ali rayes ◽  
Manel moncer ◽  
Irene Ara ◽  
Dege Necmi ◽  
Brahim Ayed
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Chemical Characterization ◽  
Chair Conformation ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
3 Dimensional ◽  
Physico Chemical ◽  
Ft Ir

Abstract Two new organic-inorganic hybrid materials, based on 1,3-CycloHexaneBis-(Methyl Amine), abbreviated CHBMA, namely(H2CHBMA)ZnCl4.2H2O (CP1) and (H2CHBMA)CdI4.2H2O (CP2), have been synthesized under mild conditions in acidic media and characterized by single-crystal X-ray diffraction, spectroscopic techniques (13C NMR, FT-IR, RAMAN) and thermal analysis. The crystal structures of the two compounds were solved by single-crystal X-ray diffraction methods. Both compounds show a 3-dimensional supramolecular structure directed by various interactions between tetrahalidometallate anions (ZnCl42-, CdI42-), water molecule and organic cations (H2CHBMA)2+. For both compounds, the cyclohexane ring of the template cation is in a chair conformation with the methyl-ammonium substituent in the equatorial positions and the two terminal ammonium groups in a cis conformation but with two different orientations (upward for CP1 and downward for CP2) which influences the supramolecular architecture of the two structures. Hirshfeld surface analysis and the associated two-dimensional finger print plots were used to explore and quantify the intermolecular interactions in the crystals.

Sign in / Sign up

Export Citation Format

Share Document