Applied Chemistry Today
Year:2024 | Volume:19 | Issue:70|Papers Count:18

In this research, using a suitable method and in line with the development of green chemistry, chitosan particles were prepared through the process of deacetylation from Persian Gulf shrimp shell waste, and then a copper-based complex was successfully synthesized on a substrate of chitosan particles, and with Techniques such as Fourier Transform Infrared Spectrometry (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Energy Diffraction Spectroscopy (EDX), Elemental Mapping, and Visible-Ultraviolet Spectroscopy (UV-Vis) was investigated. A wide variety of biaryl compounds were successfully synthesized through the developed catalytic process. The use of chitosan-copper (II) complex catalyst in the synthesis of biphenyl derivatives showed several advantages, including mild reaction conditions and short synthesis time, significant efficiency, avoiding the production of toxic waste, and easy separation of the catalyst. Furthermore, the chitosan-copper(II) complex was easily recovered by filtration and could be reused for five cycles without losing its structural integrity and catalytic activity.

In this work, the vapor-liquid equilibrium behavior of aqueous ternary systems composed of choline chloride (ChCl) and imidazolium-based ionic liquids has been investigated using the isopiestic method at 25 °C. The ionic liquids used are 1-butyl-3-methylimidazolium bromide ([C4mim][Br]) and 1-butyl-3-methylimidazolium trifluoromethane sulfonate ([C4mim][CF3SO3]). The effect of ionic liquid anion on water activity, vapor pressure, and isopiestic equilibrium concentrations has been evaluated. The deviation of water iso-activity curves from the linear isopiestic relation has been used as a benchmark to unveil the salting-out or salting-in effect of ChCl on the aqueous solution of ionic liquids. The results show that ChCl plays the role of co-solvent in the studied systems and increases the solubility of the ionic liquids in water, indicating the occurrence of the salting-in phenomenon.

In this research project, a simple electrochemical method was presented with the easy conversion of the electrode surface into a nano-sized and porous structure. The nanoporous was deposited on the surface of glassy carbon electrode by chronoamperometric method by applying potential. The proposed electrode was used to measure acyclovir drug. Under optimal conditions a significant improvement in the electrochemical behavior of acyclovir was observed on the surface of the modified electrode compared to the unmodified electrode. The detection limit of 0.13 μM and the linear range of 1.99 to 19.6 μM were obtained for the determination of acyclovir at the surface of modified electrode using differential pulse voltammetric method in phosphate buffer. Satisfactory results were obtained in the determination of acyclovir with the modified electrode in blood serum samples.

The iron (III) Schiff base complex was immobilized on magnetic silica as well as mesoporous silica substrates and characterized by XRD, TEM, FT-IR, AAS, VSM techniques, and in the case of mesoporous silica, it was also identified with N2 adsorption/desorption and TGA methods. These materials were applied for oxidation of benzyl alcohols and sulfides with hydrogen peroxide as a green oxidant. The effect of catalyst structures was studied in the mentioned reactions. The results showed that using of mesoporous silica in the oxidation of sulfides and benzyl alcohols with hydrogen peroxide in the optimal reaction conditions provided a higher catalytic yield in the same or even less reaction time, The higher catalytic performance of the mesoporous substrate based on the identifications (carried out by N2 adsorption/desorption technique) can be attributed to the higher surface area of this substrate and the stronger connection of the Schiff base complex of iron (III) to the mesoporous silica (according to leaching test).

In this paper, a novel azo Schiff base chemosensor was synthesized via condensation reaction of 4-Aminoantipyrine with 1-(3-Formyl-4-hydroxyphenylazo)-3-nitrobenzene. The imine sensor was studied via spectroscopic methods IR, 1HNMR and UV-Vis. The chromogenic behavior of colorimetric chemosensor toward various anions was investigated by UV–Vis spectroscopic. The chemosensor show abrupt changes towards CN− and OAC−anions in DMF/H2O solution in comparison with other anions. Upon the addition of CN− and OAC− ions to the receptor, the color of the L solution was changed from yellow to purple that was detectable with naked-eye and without any optical instrument. No color changes towards other anions were observed. The detection limits of the azo-azomethin sensor for OAC− and CN− anions were 2.6 ×10-5 and 1.4 ×10-6 mol L-1, respectively. Using the association constant value for sensor towards OAC− and CN− anions was calculated to be 4.2 ×103 and 3.07 ×104 M-1.

Electrochemical production of hydrogen using high-efficiency catalysts is an effective way to achieve a clean and renewable energy source. Palladium as one of the best elements as a catalyst has a very high price. In the present study, the use of silver metal reduced the consumption of palladium and improved its efficiency. In this research, Pd-Ag coating was generated using the cyclic voltametric electrochemical deposition method in a deposition bath containing palladium and silver ions on the surface of graphite rods. Factors such as coating marking method, the concentration of two salts, number of cycles, and scanning speed were optimized. Various electrochemical tests were performed to measure the activity and catalytic stability of the samples in one-tenth of a molar sulfuric acid electrolyte. To study the surface characteristics of the coatings, field emission electron microscopy (FESEM) test equipped with X-ray energy diffraction (EDS) spectrometer and X-ray diffraction (XRD) tests were used. In the optimal case, the overvoltage in the current flux of -10 mA / cm2 is equal to -177.5 mV and its TOEFL slope is equal to (mV.dec-1) 120.9, which is one of the best catalytic activities. Compared to other coatings based on silver and palladium. The reasons for the high catalytic activity of the optimal sample include the synergy of silver and palladium atoms, the resulting nanocluster structure, and the high electrochemically active surface area. A very small change in the optimal potential of the electrode at a density of -100 mA / cm2 for 5 hours of electrolysis indicates the stability of the optimal electrode in working conditions and an acidic environment. The low-cost, single-step fabrication method without the use of any adhesives or binders and the very high catalyst activity and good stability of the optimal Pd-Ag sample make it possible to use this electrode commercially.

AbstractIn this study, a magnetic catalyst of phosphutangetic acid salt (ZnHPMo12O40) was prepared by substitution of protons in H3PW12O40 with zinc metal cations as a recyclable catalyst. The structural and morphology of the prepared catalysts was investigated using Fourier transform infrared spectroscopy (FT-IR), differential thermal gravimetric analysis (TGA), BET surface analysis emission scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The prepared catalyst was successfully used as an efficient and recyclable catalyst for the synthesis of 4H-pyrans. The results showed that the magnetic zinc phosphotangestic acid catalyst exhibited good catalytic activity under optimum reaction conditions and the desired products were obtained in good to excellent yields. The good activity of the zinc salt of heteropoly acid catalyst was closely related to its high specific surface area, and the synergistic effects of Lewis and Brønsted acidity. The catalyst stability was good and it can be reused six times without significant loss activity in reaction.

In the present research, the design and synthesis of polyfunctionalized pyrrole derivatives using one-pot, multi-component reactions including aromatic aldehydes, ethyl acetoacetate, thiadiazole derivatives, and nitromethane in the presence of 3-sulfonic acid 1-imidazolopyridinium hydrogen sulfate ([Simp]HSO4]) ionic liquid and under solvent-free conditions were discussed. Since pyrrole derivatives have various medicinal properties such as antibacterial, antiviral, anti-inflammatory, and antioxidant activity, and they are very important from biological and medicinal points of view, therefore, it is very important to provide efficient and green methods for preparing these compounds.On the other hand, considering the environmental pollution and the development of the green chemistry approach, and the recommendation to reduce the use of toxic solvents in chemical reactions, extensive research to find new synthetic methods based on the use of environmentally friendly solvents and catalysts that lead to the reduction of waste materials and products. This method used the ionic liquid 3-sulfonic acid 1-imidazolopyridinium hydrogen sulfate ([Simp]HSO4]) as a recoverable catalyst in the green synthesis of pyrrole derivatives.This method has some advantages such as high yield, no use of organic solvents, mild reaction conditions, short reaction time, and easy separation without using chromatography. The structure of all products was characterized using physical data as well as 1HNMR, 13CNMR and IR spectrum.

This research used a simple and efficient liquid-phase microextraction method based on deep eutectic solvents for preconcentration and spectrophotometric determination of purpurin (1, 2, and 4-trihydroxyanthraquinone) dye. The choline chloride-acetic acid DES with a molar ratio of 1:2 was synthesized and used with 1-Decanol as the extraction solvent. The influence of effective parameters on the extraction efficiency, including the type and volume of extracting solvents, pH of sample solution, the molar ratio of DES components, and sodium chloride salt concentration were studied, using the response surface method. The highest extraction percentage (>95%) was obtained at pH = 5.5, 550 mg/L of sodium chloride, 350 and 500 µL of DES, and 1-Decanol solvents, respectively. The effect of different ions and dyes on the extraction efficiency was examined and the results indicated that the method has an acceptable selectivity. The present process was linear in the concentration range of 5.0×10-7 to 2.0×10-5 mol/L of purpurine, with a detection limit of 2.7×10-7 mol/L, preconcentration factor of 100, and a relative standard deviation of 3.13%. Finally, to test the applicability of the proposed method, it was investigated for the uptake of purpurin from various water samples, successfully.

This study aims to provide a green process implementation method for treating brine in the desalination system of brackish water with two stages of reverse osmosis. In this study, real samples taken from the first and second stages of the brackish water reverse osmosis (BWRO) plant were utilized to assess the performance of innovative sequencing batch electrocoagulation reactors (SBERs) with complementary processes (addition of chemicals and antiscalants, settling, microfiltration, UV, and ultrafiltration). According to the measurements, the TDS of the brackish water taken from the aquifer ranged from 3,229 to 3,664 mg/L, whereas that of the first-stage RO brine was between 5,500 and 7,700 mg/L, that of the second-stage RO brine was between 9,500 and 10,600 mg/L, and that of tap water was between 278 and 408 mg/L. The results of the study showed that the average removal of TDS, hardness, and ions in direct current (DC) was higher than in alternating current (AC) and that for Al-Al electrodes is more than that for Al-Fe electrodes. For the samples that were taken from the brine to the second stage RO with a TDS level of 9423 mg/L (with an increase in pH to 9 and with a temperature of 11 °C), the amount of TDS removal was 14%, and the amounts of hardness and scaling ions like calcium, magnesium, and sulfate (the amount of sulfate in quantities above 1400 mg/L) were removed equal to 35.5, 29, 35, and 30%, respectively. The TDS can be successfully reduced by electrocoagulation and scale-forming precursor ions can be eliminated by combining electrocoagulation and chemical precipitation.The results of the research showed that the third alternative was more advantageous than the others for the development phase of the desalination system under study after multiple options were analyzed technically, environmentally, and economically. The results of the research showed that the third alternative was more advantageous than the others for the development phase of the desalination system under study after multiple options were analyzed technically, environmentally, and economically.This option will direct brackish water to two RO (one stage)/SBERs processes. The RO desalination plant's brine and the SBER effluent are then combined to provide industrial water or irrigation water for plants that can tolerate salt. This method has been proposed as the best option for desalination system development because it reduces the total volume of rejected brine and increases the water supply (drinking, industrial, or agricultural).

In this research, a photocatalytic reactor made of quartz was designed and built. Then ZnO nanophotocatalysts modified with different percentages of Ag and Zr were synthesized by combustion method and using microwave. Photocatalytic experiments showed that nanophotocatalysts with a mass ratio of 0.093 Ag and 0.04 Zr are more efficient. The characteristics of this catalyst were evaluated by XRD, SEM and FT-IR analyses. Then the photocatalytic activities of ZnO-Ag-Zr in the degradation of reactive red dye 198 were investigated and the effective factors such as pH of the solution, amount of catalyst and initial concentration of the solution were investigated. Experiments showed that the optimal conditions for decolorization of the dye at a concentration of 20 mg/liter are: pH=10 and the amount of catalyst is 0.3 g/liter, and under these conditions, decolorization is above 92%. Also, in the study of the kinetics of the aforementioned reaction, it was shown that the removal rate of Reactive Red 198 dyes is in good agreement with the pseudo-first-order Langmuir-Hinshelwood equation, and therefore, the kinetic parameters were determined using this model.

A microbial fuel cell (MFC) is a device that converts chemical energy into electrical energy through the catalytic processes of microorganisms. In this study, flexible and porous WO3/CNTs-Graphite-PVC film was fabricated through uniform adding of Zn powder into matrix of carbon nanotubes-graphite- Polyvinyl Chloride) PVC (film followed by selective dissolving of Zn from the film structure in acidic solution and finally electrodeposition of WO3 (Tungsten trioxide) into previously porous CNTs-Graphite-PVC film. Surface morphology studies showed that the flexible film has rough and porous structure and carbon nanotubes are uniformly present as electron conduction channels within the composite film. Studies also showed that porous WO3/MWCNTs-Graphite-PVC film as a bioanode in MFC at resistance of 1000 ohms and current density of 900 mA/m2 has a power density of 324 mW/m2. The method presented in this research can be used as a suitable method for preparing of suitable electrocatalysts based on commercial graphite powder in microbial fuel cells.

Nowadays, fire retardants are very important. These materials are added to flammable items to increase their resistance to flammability. Zinc borates are an important class of the fire retardants, which have been prepared in this paper using two different precursors. In the first method, tris(ethylenediamine) zinc(II) tetraphenyl borate complex, [Zn(en)3](BPh4)2, was prepared by reaction of ZnCl2 with en ligand in the presence of NaBPh4 in water solvent. The prepared Zn(II) complex was calcined at 650 ºC to obtain zinc borate. In the second method, a mixture of H3BO3/ZnO with a mole ratio of 6:2 was reacted under the hydrothermal operation at 200 ºC, and zinc borate was obtained. The prepared zinc borates were characterized by different methods including FT-IR, XRD, SEM, and TGA. In addition, the application of the prepared zinc borates as a fire retardant was investigated for poly(acrylonitrile) (PAN) polymer. The results show that the addition of zinc borate to PAN increased its resistance to flammability and the combustion process immediately terminated when the sample removed from the flame. Therefore, the prepared zinc borates are good candidates for use as fire retardants in polymers.

In this article, using the structural parameters called the concentration-concentration fluctuation factor in the long wavelength limit, the number-number factor in the long wavelength limit, the partial number-mole fraction structural factor, the mixed structural factor in the long wavelength limit and calculating the short order factor Chemical field, we have studied the structure and relative investigation of interactions in binary mixtures including butyl acetate and normal alcohols (1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol) at a temperature of 298.15 degrees. Using the experimental values of molar volume and compressibility coefficient of the mixtures, the mentioned structural parameters were calculated. The effect of increasing the length of the alcohol chain on the mentioned parameters was studied, and using the obtained results, a discussion was made about the regularization or disorder of the solutions. The experimental values of the additional molar volume for all the mentioned systems are positive and increase with the increase of the length of the alcohol chain. The analysis of the mentioned structural parameters for binary mixtures also led to similar results for the strength of bonds and the amount of disorder in them. In general, it can be concluded that the intermolecular bonds in two-component systems containing butyl acetate and normal alcohols are weak, and the amount of disorder in these solutions is greater than the amount of disorder in ideal solutions, and this disorder increases with the increase in the length of the alcohol chain. The increase of these irregularities, which is caused by the weakening of the bonds in the solution, can be considered as a result of the spatial hindrance caused by the non-polar chain of alcohols. With the increase in the length of the chain, the amount of this spatial hindrance also increases.

The current study aimed to investigate the antifungal activities of cumin, black cumin, and lavender essential oils and their maltodextrin-based coatings against Fusarium oxysporum, one of the most locally predominant tomato fungal pathogens (Tehran, Iran). Also, investigation of some qualitative characteristics of coated tomato fruits during storage was aimed. The phytochemical constituents of the essential oils were evaluated using GC and GC–MS methods. Also, the inhibitory activities of the oils were examined against spore germination, mycelial growth, and fungal infection development on tomato fruits. According to the results, cuminaldehyde (34.54 %), γ-terpinene (18.30 %), p-cymen-7-ol (13.19 %) and p-cymenene (12.82 %) in cumin, carvone (28.74 %), p-cymen-7-ol (12.02 %), p-cymenene (11.55 %), safrole (8.93 %) and β-pinene (5.88 %) in black cumin, and camphor (19.11 %), eucalyptol (15.90 %), α-pinene (6.69 %), 3-carene (6.50 %) and β-Caryophyllene (5.38 %) in lavender essential oil were determined as main components. In spore germination assay, cumin, black cumin, and lavender essential oils exhibited potent activities with IC50 values of 1.05, 0.64 and 0.89 mg/mL, respectively. While, kresoxim-methyl (a standard antifungal agent) inhibited the fungal strain with IC50 value of 0.11 mg/mL. Furthermore, black cumin oil showed the most activities against mycelial growth of fungus. Furthermore, the coating enriched with black cumin oil showed the most inhibitory activity to reduce fungal growth on inoculated fruits, with a severity reduction of 79.2%. Whereas, cumin and lavender coatings showed significant activities with 71.43 and 38.09% inhibition, respectively. The results indicated that black cumin coating is a potent antifungal coating that of interest for the bioactive packaging of tomato fruits to extend their shelf life.

In the electric discharge machining process, the material is separated from the surface of the work piece by an electric spark, and in the presence of the dielectric material and tool electrode, changes are made on the surface of the work piece. In this project, we investigated the effect of dielectric material and brass tool electrode diffusion on the surface of carbon steel workpiece by means of quantmetric analysis, X-ray diffraction and electrochemical impedance spectroscopy. The effect of the parameters such as electric current intensity (I), pulse on time (ton), pulse off time (toff) and machining time (τ) on the composition of work peace, microstructure and electrochemical corrosion of machined work peace, were investigated. The results of quantmetric analysis showed that with the increase of machining parameters, the amount of diffused copper (from brass tool electrode) and carbon (from pyrolysis of flashing dielectric material) on the surface of machined carbon steel was increased. X-ray diffraction results confirmed that the formation of different phases such as Fe1.92C0.08, Cu4, Cu2 and Fe2 on the surface of workpiece, which was accordance with the quantmetric results. Electrochemical studies showed that during the EDM process, the electrochemical corrosion resistance was increased.

In this research, bentonite/nanochitosan nanocomposite was synthesized and used as an adsorbent to remove iron (ΙΙΙ) ions from aqueous solutions. The structural features and morphology of the nanocomposite surface were evaluated using FT-IR, XRD, and SEM methods. The effect of important parameters on the removal of iron (ΙΙΙ) ions, including the effect of pH, contact time, and the amount of adsorbent was investigated, and the highest removal efficiency of 99% was obtained in the amount of adsorbent of 0.003 g, pH = 4, and contact time of 20 min. investigation of adsorption isotherms showed that the Langmuir model had the best agreement with the equilibrium data and the maximum adsorption capacity was determined to be 333.33 mg/g of the adsorbent. According to kinetic studies, the removal process of iron (ΙΙΙ) ions by nanocomposite follows the pseudo-second order kinetic model and the removal rate is high Based on the findings, bentonite/nanochitosan nanocomposite with advantages such as high absorption capacity, short reaction time and compatibility with the environment, is an effective and strong adsorbent in removal of iron (ΙΙΙ) ions from aqueous solutions.

In this research, a simple and selective electrochemical sensor with high-sensitivity was proposed to detect dopamine. For this purpose, a nanocomposite consist of nickel-multiwalled carbon nanotubes and titanium dioxide nanoparticles was used to modify the carbon paste electrode. The surface morphology of the modified sensor was evaluated by field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectrometry (FTIR). Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques were used to analyze of the proposed modified electrode electrochemical behavior and to characterize dopamine. The modified electrode used in this study showed an excellent electro-oxidation response to the presence of dopamine. In addition, to optimize the electrochemical sensor response, any change in the voltammetric behavior of dopamine under different pH and scan rates conditions were investigated and phosphate buffer solution was used for this purpose. Under optimal conditions, the dopamine electrocatalytic peak currents are linearly dependent on the dopamine concentration in the range of 0.3-100 µM and the detection limit of 11.68 nM was calculated for it. Also, electrochemical parameters such as the transferred electrons number and the electron transfer coefficient were estimated. The present study findings showed that the sensor has high sensitivity, low detection limit, fast response, long-term stability, significant repeatability and reproducibility, high selectivity and recovery, as well as excellent performance in analyt detection in the real samples, which proves that the proposed electrode can be used in food, medical and environmental applications. The proposed method is simple, fast and inexpensive and can be used as a valuable analytical tool in quality control of the pharmaceutical industry.