نشریه شیمی کاربردی روز
پیاپی 43 (تابستان 1396)

A considerable quantity of the world’s oil reserve is located in naturally fractured carbonate reservoirs, with very low oil recovery efficiency, due to their wettability abd tightness of matrix. Recovery efficiency can be improved considerably, if the reservoir rock wettability is changed from mostly oil-wet to water-wet, thus enhancing water imbibition into the oil saturated rock. Smart water is able to alter the carbonate rock wetability from oil-wet to intermediate to water-wet, and therefor, water imbibition into the rock matrix is facilitated. In this study, the effect of ions and different surfactants concentration in the smart water on the wettability state of carbonate rocks was investigated by contact angle measurements and spontaneous imbibition experiments. Imbibition experiments were performed at three temperature level(50, 70 and 90 C). The effect of ions, temperature, and surfactant concentration on the wettability alteration of carbonate rocks during spontaneous imbibition process were invistegated. The results showed that the presence of SO42- ions, the strongly affects the wetting state of carbonate rocks, and increasing SO42- concentration from 0.033 mol/l to 0.1 mol/l increased the oil recovery from 19% to 58%. Moreover, by increasing Mg2 concentration the oil recovery increases (from 19% to 23%). Also the presense of cationic surfactant C12TAB, strongly changed the wetting state of carbonate rocks, and also increased the oil recovery from 19% to 78%.

A simple and efficient method has been presented for the synthesis of tetrahydropyridine derivatives via one-pot reaction of aromatic amines (2 eqv), β-ketoesters (1 eqv) and aromatic aldehydes (2 eqv) in the presence of N,N,N′,N′-tetramethylguanidinium acetate [TMG][Ac]. The reaction was carried out in EtOH under reflux conditions. Some of the advantages of this procedure are green and safe solvent, high atom economy, high yield, and no need to column chromatography for product purification. Moreover, the catalyst is recyclable and can be used up to four times without significant loss of its activity.

In this study, the complexation reaction between Cu2, Zn2 and Ag cations with 1,8-dihydroxyanthraquinone (DHAQ) and 1- (methylamino) anthraquinone (MAAQ) was studied in (AN/MeOH) binary mixtures at different temperatures using conductometry method. The conductivity data indicates in all cases, the stoichiometry of the complexes is [ML]1:1 except for the complex formation reaction between Cu2 cation and DHAQ ligand in pure methanol and in AN/MeOH (mol% AN = 75) binary solutions was obtained [M2L] 2:1. The stability constants of complexes were calculated using Genplot software and non–linear fitting of conductometric data. Also, the experimental data show that the selectivity order of DHAQ and MAAQ for Cu2, Zn2 and Ag cations, in addition to the ligand, changes with mole fraction of a component of the solvent in AN/MeOH binary mixtures. The value of &DeltaHºc for formation of complexes was obtained from temperature dependence of the stability constants of the complexes using the Vant Hoff plots and linear fitting using mentioned software. The results showed the complexation reaction between Cu2, Zn2 and Ag cations with DHAQ and MAAQ in this binary mixtures are endothermic and, in all cases the resulting complexes are entropy stabilized but enthalpy destabilized. Also, the T&DeltaSºc versus &DeltaHºc plot of all thermodynamic data indicated a fairly good linear correlation indicating the existence of the enthalpy– entropy compensation in the complexation reactions.

Nowadays, enzyme immobilization on the nano carriers was applied in food industry. In this study, Inulinase enzyme was immobilized on the magnetite nanoparticles functionalized with protein nanoparticles through covalent attachment. Inulinase can produce high fructose syrup from inulin in a one-step enzymatic process. The Inulinase was immobilized in order to increase enzyme stability under extreme conditions of industrial processes, reusability, reduce the risk of environmental pollution with the enzyme protein, reducing the cost of the final products and the ability of using bioreactors with immobilized enzyme in continuous system. In addition, the immobilized enzyme on the magnetite nanoparticles can be separated from the reaction medium by a magnetic field and it is not necessary to use of other uneconomical methods such as centrifugal separation and filtration. Therefore, in the first step, the magnetite nanoparticles were prepared by co-precipitation method. Then, in the second step, the soy protein isolate nanoparticles were synthesized by cold gelation method and then the magnetite nanoparticle’s surface was coated for modification and stabilization. In the third step, the enzyme was immobilized on the magnetite carrier through covalent attachment via glutaraldehyde. In this study, scanning electron microscope (SEM), dynamic light scattering (DLS) and fourier transform spectroscopy (FTIR) were used for analyze the particle size, shape, morphology and functional characteristics of magnetite nanoparticles and enzyme immobilization in all steps of preparation. Based on the SEM results, the size of nanomagnetite were in the range of 20 to 50 nm with the mean diameter of about 35 nm. The nanomagnetite obtained possessed spherical morphology, uniformly distributed. The size of soy protein isolate (SPI) nanoparticles according to the initial SPI amount (gr %) were in the range of 100-600 nm by using DLS technique. FTIR method confirms proper enzyme immobilization on the functionalized nanomagnetite by protein.

In this study, nano-silica particles were synthesized from tertraethylorthosilicate (TEOS) precursor and then, together with polypyrrole polymer, a nanocomposite was prepared and used for removal of reactive red 198. Scanning electron microscope (SEM) was applied to determine the superficial morphology, Transmission electron microscope (TEM) to measure the synthesized nano-silica particles and finally, the Fourier transform infra-red spectroscopy (FTIR) to confirm and functionalize the nano-silica particles together with polypyrrole polymer. Parameters affecting the removal of RR 198 such as pH, the amount of adsorbent, dye concentration, temperature, and contact time were investigated and optimized. Uv-vis spectrophotometer was used to determine the concentration of dye in the solution. The Langmuir and Freundlich adsorption isotherm models were applied for determine the adsorption isotherm equation and the presented results show very good agreement with Langmuir adsorption isotherm with high adsorption capacity of 312.5 mg/g. In addition, pseudo-second order kinetic equation was best fitted for adsorption kinetic model. The Gibbs free energy and enthalpy data verified its spontaneous and endothermic nature.

A green, simple and efficient procedure has been developed using nano α-Al2O3/MoO3 as a heterogeneous catalyst for the synthesis of bis-(4-hydroxycoumarin-3-yl)-methanes via the condensation of 4-hydroxycoumarin with aldehydes in water. High yields, short reaction times, no chromatographic separation, and recyclability of the catalyst are the advantages of this procedure.

In this research, orthoferrite neodymium nanoparticles (NdFeO3) synthesized via the Co-precipitation method and the oleic acid )C17H33COOH) was added as surfactant to control the particles size. The spherical NdFeO3 nanoparticles with an average particles size of 28 nm were obtained in calcination temperature of 800 °C for 4h. Co-precipitation method is a simple and inexpensive method for the production of mixed oxides with high purity. The morphology, lattice parameters and size of nanoparticles of product have been studied and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) techniques. The XRD analysis shows only the pattern corresponding to perovskite-type NdFeO3 which crystallizes in the orthorhombic system. The average particles size of the nanoparticles was measured both by XRD and SEM and the results were in very good agreement with each other. Also, the results indicate that the amount of surfactant, pH and rate of stirring of solution has an important role in the homogeneity and particles size of product.

Synthesis of 1,4-disubstituted 1,2,3- triazoles in the presence of SMI-CuI catalyst has been modeled by means of density functional theory in terms of structural and thermochemical aspects in the gas phase and also in the presence of three different solvents; ethanol, acetonitrile and water via polarized continuum model. Based on the calculated thermodynamical properties of the reaction, we have shown that the production of 1,4 disubstituded 1,2,3-triazole is more favourable thermodynamically. Moreover, from thermodynamic point of view, we have determined acetonitrile as more appropriate solvent.
In the next step, the structural and energetic properties of the corresponded transition states to 1,4 and 1,5 disubstituted 1,2,3-triazole products, considering SMI-CuI catalyst effect, were assessed to interpret the origins of regioselectivity. Additionally, we have analyzed the regioselective behavior of the synthesis electronically, based on the quantum theory of atoms in molecules calculations.

Carbamazepine (CBZ) is an anticonvulsant drug used in the treatment of epilepsy. However, the HPLC technique for determination of CBZ has advantages of accuracy and excellent resolution, the cost of the equipment, time-consuming steps and high maintenance limit its application. In this work, we have developed a new electrochemical sensor for the determination of CBZ. In this research, modified carbon past electrode (CPE) was fabricated by ZSM-5 nanozeolite, graphite powder and paraffin oil. Then, the electrochemical oxidation of the modified electrode towards the oxidation of CBZ investigated by voltammetric methods. Differential pulse voltammetry (DPV) peak currents increased linearly with concentrations of CBZ at the ranges of 0.35-95 µM with detection limits of 0.1 µM. The fabricated ZSM-5/CPE was provided an excellent sensor for the determination of CBZ with good reproducibility and recovery and very low detection limit. The method has been applied to the determination of CBZ in real pharmaceutical dosage forms such as human plasma and can be used in samples of hospital.

The simultaneous determination of New fushin and Victoria blue mixtures by spectrophotometric method is a difficult problem in analytical chemistry, due to spectral interferences, by multiariate calibration methods, such as partial least square (PLS) regression, it is possible to obtain a model adjusted to the concentration valuse of the mixtures used in the calibration range. Orthogonal signal correction (OSC) is a preprocessing technique used in the information unrelated to the target variables based on constrained principal component analvsis. OSC is a suitable perprocessing method for partial least squares calibration of mixtures without loss of prediction capacity using spectrophotometric method. In this study, the calibration model is based on absorption spectra in the 400-700 nm range for 25 different mixtures of New fushin and Victoria blue Calibration matrices were formed form samples containing 0/75-7/5 and 1/5-18 mg/L for New fushin and Victoria blue, respectively. The RMSEP for New fushin and Victoria blue with OSC-PLS were 0.0435 and 0.0477 µg/mL, respectively. This procedure allows the simultaneuse determination of New fushin and Victoria blue in synthetic and real samples and good reliability of the determiation was proved.

Generation 2 polyamidoamine (PAMAM) dendrimer with ethylenediamine cores (G2.O) were grafted on chitosan (CS) and evaluate as new absorbent materials. Fourier transform infrared (FT-IR) spectra data characterized that the effective graft of PAMAM onto CS and synthesis of chitosan-dendrimer (CS-PAMAM) as new adsorbent. Effect of new adsorbent onto removal of cadmium, chromium and nickel ions which are classical pollutions commonly found in industrial wastewater are investigated. Effective factors that influenced the removal efficiency of metal ions are: pH of solution, contact time, initial concentration of cations ions and dose of adsorbent were studied by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. Metal ion removal was achieved over a large-scale metal concentration within 30 minutes equilibrium time and Maximum removal of cations of heavy metal ion was obtained at  for both Cd(II) and Cr(III), and  for Ni(II). Kinetic studies showed that adsorption process of Cr(III), Cd(II) and Ni(II) followed the pseudo-second-order kinetic model. Equilibrium adsorption isotherm data indicated a good fit to the Langmuir isotherm and the maximum adsorption capacities for the Cr(III), Cd(II) and Ni(II) were 47.074, 25.814 and 33/564 ,respectively. Overall, results of the study demonstrate the potential of CS-PAMAM as new adsorbent for the removal of heavy metals from aqueous solutions.

In this study, dispersive Liquid- Liquid microextraction (DLLME) as highly sensitive procedure was developed for preconcentration and determination of paranitroaniline in textile industrial wastewater samples. Initially, a mixture of 200 &muL of dicloromethan (Extracting solvent) and 800 &muL of acetone (disperser solvent) was rapidly injected by a syringe into 9 mL aqueous sample containing 0.02 mg L-1 paranitroaniline (analyte). Thereby, a cloudy solution formed. After centrifugation, the fine droplets containing the extracted analyte were sedimented at the bottom of the conical test tube. This phase was collected by a microsyring and after dilution by acetone, 100 µL of it was transferred into the spectrophotometer for analysis. The Samples of analysis at wavelength of 375 nm was done. The calibration curve of method was linear in the rage of 0.025- 0.35 mg L-1 paranitroaniline with a detection limit of 0.01 mg L-1 and a relative standard deviation (RSD) for five replicate measurements of 4.97% at 0.025 mg L-1 paranitroaniline. Recovery values in different concentration levels in the range of 96.2-98% and the enrichment factor of 23.2 was obtained.

Influence of 2,3 dihydro-2-imino-3-p-tolylbenzo[d]oxazol-5-ol as a inhibitor on the corrosion of stainless steel 316L (SS) in HCl solution was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of the investigation show that this compound has excellent inhibiting properties for SS corrosion in sulfuric acid. Inhibition efficiency increases with increase in the concentration of the inhibitor. The adsorption of inhibitor onto the SS surface followed the Langmuir adsorption model with the free energy of adsorption ΔG0ads of -7.25 kJ mol-1. Quantum chemical calculations were employed to give further insight into the mechanism of inhibition action of new organic inhibitor.

Industrial wastewater containing synthetic dyes is an important factor in environmental pollution. Among the numerous methods that have been investigated to remove dyes, adsorption process using biosorbents is a good option for the removal of dyes from wastewater due to low cost, availability and lack of environmental risk. The aim of this study is to investigate the adsorption of cationic dye methylene blue using Iranian Luffa Cylindrica in a batch system. The effect of operational parameters including: contact time, pH and temperature on removal of methylene blue with Iranian Luffa in same condition, i.e, initial dye concentration 25 mg/L and adsorbent dose 0/5 g was investigated. Finally, data was analyzed using four kinetic and thermodynamic parameters. Results showed that equilibrium was reached at 100 min. Solution with the lowest pH has the low setup take. The maximum absorption was achieved at pH 7 and 8. That due to the insignificant difference of absorption efficiency in the two pH, by considering the economical aspect especially in large scales, pH=7 was chosen as the optimum condition. Also, adsorption efficiency increases with increasing temperature. Results from studying the kinetics of adsorption indicated that adsorption process follows kinetic model of pseudo second-order. the calculated values from thermodynamic parameters showed that the adsorption of methylene blue on Luffa Cylindrica is spontaneous, endothermic and Physical. According to this study Iranian Luffa is proposed as a natural, environmental friendly adsorbent with high efficiency, low cost for effective removal of Methylene Blue from industrial wastewaters (without any pretreatment on Luffa).

In this study, nickel oxide nanoparticles was prepared by co-precipitation method and used as potential adsorbent for the removal of Aluminon from aqueous solution on a laboratory scale. Samples characterized using Fourier transform infrared spectrophotometry (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX). By Fourier transform infrared FT-IR has proven bond forming of NiO in nickel oxide. X-ray diffraction pattern (XRD) show that nanoparticles have single phase in cubic crystalline network. The size of the nanoparticles is about 57 nm. UV-VIS show that the compound can be used as an efficient Adsorbent for the removal of Aluminon in Aqueous solution. The highest efficiency accrued in 5 ppm solution and pH=3. The Obtained empirical data in optimum condition was used to model the behavior of absorption in five isotherm equations such as: Langmuir, Freundlic –Langmuir, Toth and Khan. The adsorption data were fitted well to the Langmuier isotherm. The kinetics of adsorption interactions were examined with two adsorption mechanisms, pseudo-first-order, pseudo second-order. Result show that the adsorption data has the most conformity with, pseudo-second-order model.

The novel nano lead (II) coordination compound [Pb(p-2-pcih)2] (1)) was synthesized by a sonochemical and thermal gradient methods. The new nano structure was characterized by using scanning electron microscopy (SEM), X-ray powder diffraction, elemental analysis, and thermal analysis. The single-crystal X-ray structure shows that the overall structure of 1 is a discrete coordination compound in nature. This is further extended into a three-dimensional (3-D) supramolecular structure by π-π intermolecular interactions. The coordination number of the lead(II) ions is six, PbN4O2. The morphology of the prepared coordination compound were further observed using SEM and shows that the nano structure is in cross plate shape.

Hydrochloric acid was immobilized onto the surface of amine functionalized nano‐titania. For this purpose, 2,4‐toluene diisocyanate (TDI) as a bi‐functional covalent linker was grafted onto a nano‐titania and next, the unreacted isocyanate groups were then reduced with water and finally, the prepared amine group in the previous step was reacted with hydrochloric acid in order to producing ammonium chloride salt. This efficient nanocatalyst was evaluated in the synthesis of tetrahydrobenzo[b]pyrans, which affords high yields (67-93%) and short reaction time (15-30 min). The synthesized nanocatalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, and Mohr method titration.

In this work, we used co-precipitation method for synthesis of coper chromite(CuCr2O4.CuO). Three mole ratios of Cu2ﰪ (0.4, 0.7 and1.0) was used in order to investigate the effect of these mole ratios on the phase, morphology and size of particles. Precursor samples were calcined at 500, 600 and 700ºC for each mole ratio in order to investigate the effect of calcination temperatures. Furthermore two samples were calcined at 800 and 900 ºC and two samples synthesized in the presence of sodium dodecyl sulphate as surfactant at 700 ºC. All samples were characterized by Xray diffraction (XRD), scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) analysis. XRD patterns of nanoparticles calcined at 500, 600 and 700ºC revealed that, at this range of temperature, nanoparticles have been composed of CuCr2O4 spinel and CuO. Furthermore XRD patterns showed that by changing mole ratio of Cu2ﰪ the amount of CuO remains constant at 500 and 600 ºC calcination temperatures but at higher temperature (700 ºC) the amount of CuO increases by increasing mole ratio of Cu2ﰪ. At 800 and 900 ºC calcination temperatures and Cu2ﰪ =1, CuCr2O4 spinel was not seen, this compound reacts with CuO and produces CuCrO2 at these temperatures.
SEM images of nanoparticles at 500, 600 and 700ºC calcination temperatures showed that the morphology of nanoparticles is almost like nanosheet with a thickness in the range of 20-35 nm. Big aggregation is seen due to small particle size. The best nanoparticle according to uniformity of morphology and small particle size is the sample that Cu2ﰪ is 0.4 and is calcined at 600ºC. With rising temperature and using surfactant, the aggregation reduces and crystallinity improves but the size of nanoparticles becomes large.