Journal of Applied Chemical Research
Volume:11 Issue: 1, Winter 2017

Inhibition efficiencies of three amine derivatives (Diethylenetriamine (I), Triethylenetetramine (II), and Pentaethylenehexamine (III)) have been studied on corrosion of carbon steel using density functional theory (DFT) method in gas phase. Quantum chemical parameters such as EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), hardness (η), polarizability (α), dipole moment (μ), electrophilicityindex (ω) totalnegative charges on atoms (TNC) and molecular volume (MV) have been calculated at the B3LYP level of theory with 6-311 ** basis set. Moreover, adsorption behavior of the inhibitor molecules on Fe (110) surface has been analyzed using molecular dynamics simulation. The binding strength of the concerned inhibitor molecules on Fe (110) surface follows the order III>II>I, which is in good agreement with the experimentally determined inhibition efficiencies. In consistent with experimental data, theoretical results showed that the order of inhibition efficiency is Pentaethylenehexamine (III)>Triethylenetetramine (II)>Diethylenetriamine (I). This study has shown that DFT along with MD can be successfully be used as a reliable approach to screen organic corrosion inhibitors prior to experimental validation.

Cephalexin is an important antibiotic. It is very significant to determine an appropriate method for the extraction of this valuable antibiotic for industrial applications. Aiming at developing an efficient method for the extraction of cephalexin, the partitioning of cephalexin has been evaluated in aqueous two-phase system, including cholinium chloride and potassium phosphate. The effect of three main and independent variables on the partition coefficient of cephalexin has been estimated. These variables are as follows: equilibrium temperature, different weight percent of salt, and cholinium chloride. The results showed that by increasing the salt weight percent and the temperature, the partition coefficient of cephalexin will increase, while by increasing the weight percent of cholinium chloride, its partition coefficient will decrease.

Using the Langmuir probe method, the reactive plasma parameters were studied in different ratios of oxygen and nitrogen concentrations in a DC cylindrical discharge device.The plasma parameters such as plasma potential, electron density and electron temperature wereextracted from the current-voltage characteristic’s curve of Langmuir probe to find the optimum conditions for deposit the oxynitride thin films.Chromium thin films were exposed to various O2/N2 partial pressures to obtain optimum valuefor produce of oxynitride chrome thin films. In addition, the influence of the magnetic field on the structural properties of the chrome oxynitride thin films was obtained. It is observed that for equal percentage of reactive gases, the optimum condition of the plasma discharge takes place in which the crystalline phases of oxynitride chrome thin films appear.

The interaction of human serum albumin with Ethyl 2-[2-(dimethylamino)-4-(4 nitrophenyl)- 1,3-thiazole-5-yl]-2-oxoacetate was investigated by using isothermal titration UV-visible spectrophotometry in tris-buffer, pH 7.4. According to these results, it was found that there are a set of 4 binding sites for this ligand on HSA with positive cooperativity in the binding process. This thiazole derivative can denature the protein as surfactants. Also, their binding was investigated by molecular dynamics simulation in combination with molecular docking. Parameters of surface area, radius of gyration, hydrogen bonding, RMSD, potential of mean force, diffusion coefficient, radial distribution function, helix and coil structures were obtained. It was observed that surfactant reduce intermolecular hydrogen bond and unfold HSA structure more at higher temperature.

This study describes the effects of the substituents on electrochemical behavior and antioxidant activity of the three tetradentate Schiff bases, containing ethane-1,2- diamine, propane 1,3- diamine and butan-1,4- diamine as the amine part and salicylaldehyde, and corresponding Cd(II) complexes. Cyclic voltammograms of these compounds were recorded in dimethylsulfoxide and 0.1 M sodium perchlorate as supporting electrolyte with glassy carbon as working electrode at different scan rates. The voltammograms of Schiff bases alone showed only one irreversible peak. Voltammograms recorded for complexes showed the presence of quasi-reversible processes taking place at the metal center and reversible process at the ligand part. Both steric and inductive effects of substituents and structure of imine bridge of Schiff base ligands as well as complexes were discussed. These effects appear relevant for the antioxidant activity. Antioxidant activity of the investigated compounds expressed as Trolox equivalent antioxidant capacity is also discussed. The electrochemical behavior showed a high correlation with the antioxidant activity for investigated compounds.

The complexation of Cd2 by diallyl disulfide (DADS) and diallyl sulfide (DAS) has been studied by differential pulse voltammetry. Stability constants, (log β), of the 1:1 (PbL) and 1:2 (PbL2) complexes, where L = ligand, were found to be in the range of ca. 5.8 - 6.2 and 9.6 -10.6, respectively. Complex formation is accompanied with a significant decrease in the peak current and the shift of the Cd2ﰧ half-wave potential to a higher one upon the addition of the sulfur containing ligands (L). The formation of 1:1 and 1:2 complexes, i.e., CdL2 and Cd 22 was observed in the case of the two ligands. The consecutive formation constants of labile lead complexes with DADS and DAS were determined at 298K by the method of DeFord and Hume. Apparently due to the large size of the cadmium ion, steric hindrance caused by the greater steric bulk of DADS compared to that of DAS have little or no effects on the formation constants, so that very similar values were obtained in the case of the two ligands. Also, the possible participation of C=C double bonds in coordination with the metal center in the case of DADS appears to compensate for the steric effects caused by the larger size of this ligand. In agreement with the Jorgensen principle of symbiosis, the second formation constants were found to be approximately six orders of magnitude greater than the first ones.

A highly selective copper (II) coated graphite sensor was prepared by 1,13-bis(8 quinolyl) 1,4,7,10,13-pentaoxatridecane (kryptofix 5) as a supramolecule ionophore into plasticized polyvinyl chloride (PVC) membrane. The best response characteristic was observed using the membrane composition of PVC = 30.0 mg, dioctyl sebacate (DOS) = 63.5 mg, palmitic acid (PA) = 3.0 mg and kryptofix 5 = 3.5 mg. The sensor exhibits a nernstian slope (30.0±0. mV/ decade) in a wide linear concentration range of 1.0×10-5 to 1.0×10-1 M with detection limit of 8.7×10-6 M. The electrode has a fast response time of 15 s with a satisfactory reproducibility and relatively long life time of about 16 weeks without significant drift in potential. The sensor operates in the wide pH range of 2.0-10.0. This sensor reveals a good selectivity towards Cu2 ion over a wide range of alkali, transition and heavy metal cations. The electrode was used as an indicator electrode for potentiometric titration of Cu2 using EDTA solutions. The proposed sensor was applied for the direct determination of Cu2 cation and the results were compared with those obtained from atomic absorption spectrometric analysis and were found in good agreement. Also this sensor was successfully used for determination of copper (II) in real samples.

In this work La0.7Sr0.3MnO3, one group of nanosized perovskite-type oxides were prepared by sol-gel method. The perovskite structure has been characterized by X-ray diffraction (XRD) , scanning electron microscopy (SEM) , energy dispersive X-ray spectrometer (EDX) and Fourier transform infrared (FTIR) . The nanoparticles showed the excellent adsorption properties towards reactive blue 4 (RB4) as a reactive dye. The adsorption studies are carried out at different pH values, different adsorbate concentrations, various adsorbent dosages, different temperature, and contact time in a batch experiments to find the optimum conditions.

Three-component reactions have emerged as useful methods because the combinationof three components to generate new products in a single step is extremely economical,among the multi-component reactions. A green, simple, efficient, and cost-effective procedure has been carried out by the synthesis of dihydropyrimidinonesin Biginelli’s condensation of ethyl cyanoacetate, aldehyde and urea or thiourea .H3BO3, H2C2O4, Me3SiCl (TMSCl) using as catalyst and compared product yield.Products were characterized with IR, 1H NMR, 1 C NMR and mass spectroscopy.

A mild and efficient synthesis of polysubstituted dihydro-2-oxypyrroles has been developed for the one-pot, four-component domino condensation of dialkyl acetylenedicarboxylate, formaldehyde and aromatic amines using Vanadium (V) oxide as the catalyst at ambient temperature. The use of Vanadium (V) oxide makes this process simple, more convenient, and environmentally friendly.

This study investigated the optimum conditions for the leaching of manganese-rich iron ore for subsequent beneficiation studies in laboratory scale. The experiments were carried out by varying the concentration of H2SO4 solution and the leaching temperature. The properties of the iron ore was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) as well asphoto-micrographic examination. The leaching experiments showed that the ore leaching increases with increasing acid concentration and temperature. About 78.9% of the iron ore was reacted within 120 minutes by 4M H2SO4 solution at a temperature of 80oC. The activation energy (Ea) and the order of reaction were determined to be 31.14kJ/mol and 0.979, respectively. The leaching data were fitted to the shrinking core model and the experimental results followed a diffusion controlled mechanism. The residual product at optimal leaching was appropriately characterized and was found to contain silicate compound.

The present work was undertaken to evaluate the feasibility of nickel (II) removal from aqueous solution by adsorption onto a biopolymer adsorbent. The adsorbent was prepared using modification of mesoporous silicate SBA-15 with alginate biopolymer (alginate- SBA-15) by encapsulation method. Morphological structure of the obtained nanocomposite adsorbent was characterized by XRD, scanning electron microscopy, nitrogen porosimetry technique, and fourier transform infrared spectroscopy. Batch adsorption experiments were carried out to investigate influence of operational parameters such as pH, contact time and initial concentration on alginate-SBA-15 adsorption behavior. Kinetics study revealed that the pseudo-second-order model provided well mathematical description of the experimental data. Out of several isotherm models, the Langmuir, Ferundlich, Dubinin-Radushkevich, Redlich- Peterson, and Temkin models were applied to adsorption data to estimate adsorption capacity. The equilibrium adsorption data are well modeled by the Langmuir isotherm than the others and the maximum adsorption capacity found to be 58.82 mg g-1.