نشریه شیمی کاربردی روز
پیاپی 61 (زمستان 1400)

In this study, the synthesis of a magnetic multi walled carbon nanotubes nanocomposite hydrogel (MMWCNT/Hydrogel) are investigated.(2-dimethylaminoethyl) methacrylate monomers were grafted onto the sodium alginate backbone via initiation by ammonium persulfate (APS), and at the same time, the crosslinking were occurred by using N,N'-methylenebis(acrylamide) (MBA). Factors affecting the water swelling during the hydrogel synthesis, including monomer concentration, MBA concentration and APS concentration were systematically optimized. Swelling capacity was measured at various temperatures, pH values and salt concentrations, and the dependence of swelling properties of the hydrogel nanocomposite on these factors was well demonstrated. The synthesized samples were fully characterized using Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy analysis (FESEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM).

In this study, the PTA @ MIL-53 (Fe) heterogeneous catalyst was synthesized to provide a suitable alternative to Lewis acids, including rare-earth metal triflates, AlCl3, and BF3, which have been used as catalysts for Fries rearrangements. This catalyst was synthesized using a mixture of FeCl3.6H2O, and 1, 4-benzenedicarboxylic acid (BDC) and PTA in DMF solvent in the ultrasonic bath. PTA encapsulation in MIL-53 (Fe) was confirmed using XRD, FT-IR, TGA, ICP and SEM techniques. The activity of PTA @ MIL-53 (Fe) catalytic in the Fries rearrangements of O-Acyloxy benzene reaction was investigated under ultrasound illumination and the effect of parameters such as reaction time, amount of catalyst and PTA percent in structure of catalyst on the yield was studied. The results show that increasing of all three parameters lead to increase yield upper than 98 percent.

The aim of this study was to investigate the inhibitory effect of a prepared complex on the magnetic iron oxide nanoparticles to increase the surface resistance of metals against corrosion. A new chelating agent was prepared from a coupling of xanthate and chloroacetamide and then grafted on surface of iron oxide nanoparticles that were synthesized by co-precipitation method. The surface of the nanoparticles was coated with silica to stabilize against oxidation as well as to prevent their accumulation, and then this surface was modified and functionalized by amine groups. Then the prepared complex was characterized by FT-IR, SEM and NMR and its effect on metal surface corrosion in hydrochloric acid medium was investigated using electrochemical impedance test (EIS). The results were evaluated in terms of increasing inhibitory concentration, decreased surface roughness and load transfer layer resistance at the electrode surface. The results showed that with increasing the inhibitor concentration, the surface roughness decreased and the resistance of the charge transfer layer at the electrode surface increased to 356.57 Ω cm2 and the best result was obtained at a concentration of 100 ppm of the inhibitor.

NiFe2O4 nanoparticles are modified by graphene quantum dots (GQDs) and utilized to stabilize the Al(III) nanoparticles as a novel magnetically retrievable catalytic system (Al(III)/GQDs/NiFe2O4) for green formation of benzothiazoles by means of aromatic aldehydes and 2-aminothiophenol reaction. The prepared catalyst can be isolated assisted by the assistance of an external magnet and recovered for five courses without significant reduction in its efficiency. The as-prepared magnetic heterogeneous nanocomposite was characterized by UV–Vis, FT-IR, XRD, EDS, VSM, TEM, and ICP. Performing the reactions in environmentally friendly and affordable conditions (water), the low catalyst percentage, high yield of products, short reaction times, and easy workup are the merits of this protocol.

In this work, Gold coated iron oxide nanoparticles (MNPs @GLYMS@ Au-NPs) with heat therapy application were synthesized and characterized. Gold cations in the presence of honey as a reducing agent were reduced to gold nanoparticles. The magnetic properties of the modified nanoparticles (VSM) were measured using an equal magnetometer (-35 to +35) emu/g. The presence of Au-S and Fe-O bonds and the Fe3O4 spinel structure were confirmed by the FT-IR (FT-IR) and X-ray diffraction spectrometry (XRD) spectroscopy, respectively. Scanning electron microscopy (SEM) showed the spherical morphology of a surface-modified magnetic nanoparticle with a size of 45-55 nm and the morphology of Fe3O4 nanoparticles were kept after the bonding of the gold nanoparticles. The results of this work showed that nanoparticles have significant magnetic properties and surface functionalized. Because of this nanoparticles provide a useful and important tool creating an acceptable method for improving the quality of hyperthermia due to the production of effective frictional heat and rapid transfer.

Today, water is one of the most important human concerns, especially in arid areas. One of the things that can be recycled to turn it into water used for industrial or agricultural purposes and also prevent the entry of very harmful pollutants into nature, is the treatment of wastewater containing oil pollutants. In this study, the advanced oxidation process using the Fenton method was used as a new chemical treatment method. In the Fenton treatment process, the pH of the reaction, the concentration of iron (II) catalyst, the oxidizing concentration of hydrogen peroxide and the reaction time are the four main parameters that determine the treatment efficiency. Therefore, to achieve the desired efficiency and minimize the cost of treatment, the optimal value of each parameter should be determined. The results showed that the best pH for the Fenton method in removing turbidity and COD at pH equal 3 and the highest removal efficiency of COD and turbidity in catalyst concentration of 250 mg/L, the oxidizing concentration of 500 mg/L and reaction time of 40 minutes were obtained with values of 89% and 95%, respectively, which were selected as the optimal conditions. Also, the study of kinetic models to find the reaction rate showed that the Behnajady – Modirshahla – Ghanbery (BMG) kinetic model is more consistent than the pseudo-first-order and pseudo-second-order kinetic models and has a correlation coefficient of 0.9938. As a result, the Fenton process can be used as a treatment for petroleum-containing effluents.

We herein describe the fabrication of a ninhydrin (NH) incorporated sol-gel glass with nanoporous structure as an optical sensor to measure cyanide ion. Tetraethyl orthosilicate was used as precursor to form the porous polymeric network for entrapment of NH in porous silica gel matrix. Our thorough experimental-based results revealed that the porous feature of the matrix as well as its average pore size could play significant roles in almost all critical parameters, affecting the sensor performance, including sensitivity, selectivity and response time of sensor. The constructed sensors showed optimum performance under the working conditions, including water: alkoxide ratio of 4:1, water acidity of 0.1 M and ethanolic solution of NH 0.112 mol L-1. Under optimum conditions, a linear calibration curve over the range 0.003 to 5.000 μg mL−1 (1.15×10-7 – 1.91×10-4 mol L-1) of cyanide ion was obtained, along with a detection limit value of 0.0013 μg mL−1 (4.99×10-8 mol L-1). Meanwhile, the sensor exhibited excellent RSDs for both intra-day and inter-day precision.

Employing carbon dioxide as a renewable C1 building block in chemical reactions is attracting attentions in recent years. Reacting CO2 with high energy reagents such as H2 and epoxides in the presence of suitable catalysts is a strategy to overcome the thermodynamic stability of CO2. Reaction of CO2 and epoxides produces polymeric carbonates and cyclic carbonates with several practical and potential applications such as reagents in polyurethane synthesis, biodegradable polymers, and as green solvents in various reactions. In this research, metal acetylacetonate complexes of Fe(III)(acac-F3), Fe(III)(acac)3 , Ni(II)(acac)2, Ni(II)(acac-F6)2, and Co(II)(acac)2, Co(II)(acac-F6)2 are investigated as easily available catalysts in the reaction of styrene oxide and CO2 in the presence of organic halides. The effect of CO2 pressure, catalyst and co-catalyst structure is investigated. A high yield as 61% was observed at 80 ºC and 1 bar of CO2 after 3h. Increasing the CO2 pressure up to 80 bar had a significant effect on the carbonate conversion as 88% yield was obtained. With fluorinated complexes increasing the yield was even more and up to 92% yield was observed.

In this investigation, a novel nano-adsorbent based on magnetic graphene oxide nanocomposite was used for dispersive solid-phase microextraction (D-SPME) of melamine in environmental water samples. The m@GO-RAFT agents were synthesized by surface modification of Fe3O4 nanoparticles with graphene oxide via surface reversible addition-fragmentation chain transfer (RAFT) copolymerization, as characterized by electron microscopy (SEM and TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Several parameters affecting extraction performance, including the extraction solvent, amount of nano-adsorbent, contact time and back-extraction time, and sample pH were evaluated and optimized. Under the optimum conditions, analytical figures of merit such as linearity, limit of detection (LOD) and limit of quantitation (LOQ) were found to be 0.03–100 µg/L, 0.011 µg/L, and 0.027 µg/L, respectively.

In this research, a coated graphite electrode based on quetiapine as a neutral ion carrier was constructed for determination of Mg2+. The designed sensor demonstrates an ideal Nernstian slope (30.2 mV. Decade-1) over a wide concentration range (1×10-7- 1×10-2 M). The detection limit of the proposed sensor was 8×10-8 Mol L-1. The selectivity of the sensor was evaluated over 24 different cations by matched potential method and no serious interference was observed from them. The designed electrode could also be used in partially non aqueous mediums up to the presence of 20% of organic solvents without any tangible change in Nernstian slope and linearity domain. The response time and life span of the proposed electrode were 5s and 3 months respectively. The potential response of the sensor was independent from pH in the pH range of 3.0-8.0. At the end, the applicability of the designed sensor as an indicator electrode in potentiometric titration of Mg2+ with EDTA and determination of magnesium in some pharmaceutical products as real samples was also evaluated.

In this research, phase equilibria of the ternary system (water + butyric acid + methylcyclohexanol) was investigated and experimental data of liquid-liquid equilibrium were obtained at 293.2 K and ambient pressure. Solubility curve was achieved using cloud point method and Type 1 behavior was observed for liquid-liquid ternary mixture. Tie-lines were measured via acid-base and Karl-Fischer titrations. The Othmer -Tobias and Hand equations verified that the experimental tie-line points are reliable. Regression coefficients in both the equations were 0.991. Distribution coefficients and separation factors were determined over the biphasic region. The maximum and minimum values obtained for these two parameters were 5.23 and 3.84 for distribution coefficient and 48.0 and 32.7 for separation factor, respectively. The calculated values for the parameters showed that methylcyclohexanol is a proper solvent for separation of butyric acid from water. The NRTL thermodynamic model was used for correlation of experimental tie-lines. The quality of modeling was investigated using the calculation of rmsd and Gibbs free energy of mixture. The calculated value for rmsd (0.57 %) showed that modeling was done well.

In this study, the micellization behavior of the sodium cholate (SCH) and sodium dodecyl sulfate (SDS), in aqueous solution in pure state, and mixture of them (SCH + SDS) in different mole fractions were investigated by conductometric method at 298.15 K. The obtained data from experimental measurements were used to determination of the critical micelle concentration (CMC) of surfactants in pure and mixed state. Also according to Regular Solution Theory (RST), were calculated the following parameters: the interaction parameter between surfactants in the mixed system (), activity coefficient (،), mole fractions of the components in the mixed micelle (,) and thermodynamic parameters such as Gibbs free energy of micellization () and excess free energy (). The results obtained show that in the anionic-anionic mixture, the interaction parameter is low and the activity coefficients show a small deviation from the ideal state, the standard Gibbs free energy of micellization () are negative values, this shows that the micelle formation process take place spontaneously.