trans-Diaqua­bis­[2,5-bis­(pyridin-2-yl)-1,3,4-thia­diazole]cobalt(II) bis­(tetra­fluoridoborate)

The bidentate 1,3,4-thia­diazole ligand substituted by two 2-pyridyl rings (denoted L) has been found to produce the new monomeric title complex, [Co(C12H8N4S)2(H2O)2](BF4)2. The thia­diazole and pyridyl rings surrounding the Co atom are almost coplanar [dihedral angle = 4.35 (7)°]. The mean plane defined by these heterocyclic moieties makes a dihedral angle of 18.72 (6)° with the non-coordinated pyridyl ring. The Co2+ cation, located at a crystallographic center of symmetry, is bonded to two ligands and two water mol­ecules in a trans configuration in an octa­hedral environment. The tetra­fluorido­­borate ions can be regarded as free anions in the crystal lattice. Nevertheless, they are involved in an infinite two-dimensional network along the [010] and [101] directions of O—H⋯F hydrogen bonds

Synthesis and characterization of vanadium pentoxide on different metal oxides by the sol-gel process for application in the conversion of the SO2 to SO3

Sulfuric acid is the largest volume chemical currently produced in the world. Is manufactured by the contact process, it involves three stages: combustion, conversion and absorption. The SO2 conversion reaction is the key step in the process, it uses catalysis. The objective of this work is to synthesize a series of mixed vanadium oxides X% / MO2 with M (Si, Al and Ti) by sol-gel process followed by calcination at 400 ° C, in order to study their reactivity in the catalytic oxidation of SO2 to SO3. Characterization of those materials was carried out by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), X-ray diffraction, thermal analysis (TDA/TGA) and N2 adsorption at 77 K. Their acid-base properties are studied by the decomposition reaction of isopropanol (propan-2-ol). In this work, we have studied the reactivity of the catalysts prepared in the conversion of SO2 to SO3 by an iodometric as dosage which consists in assaying the iode with sodium thiosulfate

Removal of cationic dye by high surface activated carbon prepared from biomass (date pits) by carbonization and activation processes

In this work,we investigated the capacity of activated carbon (AC) to adsorb Methylene Blue (MB) from aqueous solution. AC-H3PO4 and AC-ZnCl2was obtained from date pits via a one-step chemical method using H3PO4 and ZnCl2 as activating agents. The performance of AC was characterized by different analyses techniques: proximate analysis, SEM, XRD and FT- IR and TGA. The experiments results showed that the MB removal increased by increasing each of AC-H3PO4 and AC-ZnCl2 concentration, contact time and temperature. The efficiency of the adsorption tests are evaluated by the Langmuir and Freundlich isotherm models. Equilibrium data fitted well by Freundlich modelwith a maximum of the adsorption capacity of 95 mg/g at 333 K for AC-ZnCl2, However, the adsorption was well adapted to the Langmuir isotherm with a maximum of the adsorption capacity of 125 mg/g at 298 K for AC-H3PO4. The kinetics data was explained by the pseudo second-order model, and the intra-particle diffusion with some other rate controlling steps has been suggested as the adsorption mechanism. The pseudo-second-order model described better the adsorption process. The thermodynamic study suggested that MB adsorption on AC-ZnCl2 was endothermic, spontaneous and non-spontaneous for AC-H3PO4.         

Aqua­[1-(4-carb­oxy­phen­yl)-1H-imidazole-κN 3](pyridine-2,6-dicarboxyl­ato-κ3 O 2,N,O 6)copper(II) monohydrate

In the title complex, [Cu(C7H3NO4)(C10H8N2O2)(H2O)]·H2O, the CuII ion is in a slightly distorted square-pyramidal geometry. Two carboxyl­ate O atoms and one pyridine N atom from a pyridine-2,6-dicarboxyl­ate ligand chelate the CuII ion, forming two stable five-membered metalla rings. One imidazole N atom from a 1-(4-carb­oxy­phen­yl)imidazole ligand and one water mol­ecule complete the five-coordination. O—H⋯O hydrogen bonds involving the coordinated water mol­ecules and carboxyl­ate groups link the complex mol­ecules into chain-containing dinuclear macrocycles. O—H⋯O hydrogen bonds involving the uncoordinated water mol­ecules link the chains into a layer extending parallel to (10)

Aqua­bis­[2,5-bis­(pyridin-2-yl)-1,3,4-thia­diazole-κ2 N 2,N 3](trifluoro­methane­sulfonato-κO)copper(II) trifluoro­methane­sulfonate

2,5-Bis(pyridin-2-yl)-1,3,4-thia­diazole (denoted L) has been found to act as a bidentate ligand in the monomeric title complex, [Cu(CF3O3S)(C12H8N4S)2(H2O)](CF3O3S). The complex shows a distorted octahedrally coordinated copper(II) cation which is linked to two thia­diazole ligands, one water mol­ecule and one trifluoro­methane­sulfonate anion. The second trifluoro­methane­sulfonate anion does not coordinate the copper(II) cation. Each thia­diazole ligand uses one pyridyl and one thia­diazole N atom for the coordination of copper. The N atom of the second non-coordinating pyridyl substituent is found on the same side of the 1,3,4-thia­diazole ring as the S atom. The trifluoro­methane­sulfonate ions are involved in a three-dimensional network of O—H⋯O hydrogen bonds. C—H⋯N inter­actions also occur

Thermodynamic properties of 2,5-bis(4-dimethylaminophenyl)-1,3,4-oxadiazole as corrosion inhibitor of carbon steel in hydrochloric acid pickling environment

The corrosion inhibition of carbon steel in 1 M HCl by 2,5-bis(4-dimethylaminophenyl)-1,3,4-oxadiazole (DAPO) was investigated using weight loss method in the temperature range of 303–333 K. It was found that the inhibition efficiency increases with an increase in DAPO concentration but decreases with an increase in temperature. It has been determined that the adsorption for the studied inhibitor on carbon steel complies with the Langmuir adsorption isotherm at all studied temperatures. Both kinetic parameters (activation energy, pre-exponential factor, enthalpy of activation and entropy of activation) and thermodynamics of adsorption (enthalpy of adsorption, entropy of adsorption and Gibbs free energy) were calculated and discussed

2,5-Bis(4-pyridyl)-1,3,4-oxadiazole as Efficient Organic Corrosion Inhibitor for Carbon Steel in Normal Hydrochloric Acid Medium: Influence of the Temperature on the Inhibition Process

2,5-Bis(4-pyridyl)-1,3,4-oxadiazole (4-POX) has been synthesized and studied as organic corrosion inhibitor for carbon steel (CS) in 1M HCl solution using the weight loss technique in the temperature range from 303 to 333 K. The obtained results confirmed the excellent anticorrosion properties of 4-POX and the inhibition efficiency increased with increasing inhibitor concentration and decreased with increasing temperature medium. A mixture of physisorption and chemisorption is proposed for the corrosion inhibition mechanism and the process followed the kinetic/thermodynamic model of Langmuir in the temperature range from 303 to 343 K. The adsorption and kinetic parameters for CS/4-POX/1 M HCl system were calculated from experimental gravimetric data and the interpretation of the results are given

3,5-Bis(4-meth­oxy­phen­yl)-4H-1,2,4-triazol-4-amine

The title compound, C16H16N4O2, crystallizes with two mol­ecules in the asymmetric unit, which are related by a non-crystallographic centre of inversion. The phenyl­ene rings are twisted out of the mean plane of the triazole ring by 19.3 (1) and 21.4 (1)° for one independent mol­ecule and by 16.3 (1) and 18.1 (1)° for the other mol­ecule. In the crystal, adjacent mol­ecules are linked by amine–triazole N—H⋯N hydrogen bonds, forming chains running along the a axis

Inhibitive effect of some phosphonate derivatives on the corrosion of carbon steel in 2 M H3PO4

Corrosion inhibition performance of some phosphonate derivatives, namely, dodecylphosphonic acid (YM1),  sodium methyl dodecylphosphonate (YM2) and methyl hydrogen dodecylphosphonate (YM3)  on carbon steel in 2 M H3PO4 solution was investigated by means of weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. These compounds inhibit the corrosion rate even at very low concentrations and the order of increasing inhibition efficiency was correlated with the modification of the molecular structure of the inhibitors. Polarization curves indicated that these compounds acted primarily as mixed-type inhibitors. The adsorption of these compounds on carbon steel surface has been found to obey Langmuir’s adsorption isotherm. E% values obtained from weight-loss and electrochemical methods were in good agreement. size:12.0pt;line-height:200%;font-family:"Times New Roman","serif"; color:black'>.

Hexavalent Chromium Uptake from Aqueous Solutions using Raw Biomass of the Invasive Brown Seaweed Sargassum muticum from the Moroccan Shorelines: Kinetics and Isotherms

Raw biomass of the invasive Japanese brown seaweed Sargassum muticum, recently introduced to the Atlantic coast of Morocco, has been applied for the removal of hexavalent chromium Cr(VI) from aqueous solutions. Various parameters such as biomass dose, initial pH, contact time and initial Cr(VI) concentration were studied to reveal their effects on the biosorption process. At optimum values of the above mentioned parameters, total removal of Cr(VI) can be achieved within 10 min at pH 2, adsorbent dose of 0.5 g/100 mL for initial chromium ions concentration of 50 mg/L. Cr(VI) biosorption follows pseudo second-order kinetics. Adsorption isotherms were determined at room temperature and the experimental data were modelled with the Langmuir, Freundlich and Temkin isotherm equations. The isotherm data were found to be well fitted by linear Langmuir equation. The maximum sorption capacity calculated from Langmuir isotherm was estimated to be about 143 mg per gram of dry biosorbent. Thus, the biomass used in this study can be considered a promising and valuable natural adsorbent for the treatment of aqueous solution containing toxic hexavalent chromium ions