Journal of Applied Research in Chemistry
Year:2019 | Volume:13 | Issue:3 |Papers Count:12

Phosphoramides are an important class of organophosphorus compounds, which have many applications in various industries, considering their structural characteristics. Phosphoramide ligands and their metal complexes can be highly efficient catalysts for a variety of chemical reactions, including reduction of carbonyl compounds and addition of dialkylzinc to them, allylic amination and alkylation, asymmetric allylation, epoxidation, transesterification, Pinacol coupling, polymerization, aldol, and Friedel– Crafts reactions. This review article examines the catalytic activity of mentioned compounds in various reactions. In the present work, in addition to collecting and introducing phosphoramide catalysts and catalyzed reactions, the effect of different parameters such as structure of the catalyst, temperature, and additive on rate and efficiency, have been studied. Also, for some reactions, kinetic studies have been investigated. Studies showed that acceptable yield and selectivity for phosphoramidic catalysts could be achieved by optimization of effective reaction parameters, like temperature, solvent, and the dose of catalyst loading.

In this study the effect of cobalt chromite (CoCr2O4) nanospinel on the catalytic removal of methane (CH4), as the main compound in compressed natural gas (CNG), nitrogen oxides (NOx), and carbon monoxide (CO) was investigated. For this purpose, pure and single-phase cobalt chromite nanoparticles were synthesized by coprecipitation method with the average size about 80 nm. The characterization of the obtained nanoparticles was done using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and BET analysis. For the catalytic test, cobalt chromite nanoparticles, precious metals (palladium and rhodium), gama-alumina, and cerium oxide were used as slurry in washcoat material. Catalytic activity evaluation was investigated by measuring the temperature of 50% conversion (light off temperature) of methane, carbon monoxide, and nitrogen oxides. Reducing the light off temperature of methane and nitrogen oxides showed cobalt chromite nanospinel is a suitable option for use in catalytic converter of natural gas vehicles.

In this paper, hydroxyapatite nanoparticles were synthesized and substituted by fluorine atoms. Then the prepared nanoparticles were applied for loading and releasing of ibuprofen as a drug model in a body stimulated system. At last, toxicity of nanoparticles was investigated through MTT studies. In order to study the morphology and characterizing the structures of nanoparticles Scanning Electron Microscopy and FT-IR spectroscopy were applied. Drug loading and releasing processes were investigated via TGA and UV-Visible instruments. Higher amounts of fluorine resulted in increasing crystallite sizes from 35 to 53 nm and particle sizes from 50 to 77 nm. It also enriches the drug loading and releasing amounts. HAP and FHAP are not toxic but show light toxicity by fluorine amount increasing. Ibuprofen is utilizable for loading and releasing from HAP and FHAP in body only by 25 percent concentration.

In the present research, because of hazardous effect of dyeing and textile industries wastewaters and importance of the organic pollutants elimination, polymeric nanofibers (polyamide) were obtained under high-voltage field by a spider wired semi-industrial electrospinning system (WSES). Electrospun nanofibers were characterized by FESEM, EDX, BET, FTIR, and AFM analysis methods. The optimum conditions of dye adsorption using the fibers were achieved at 0. 04 g of polyamide, pH=2 and 750 rpm. The results also showed that the calculated equilibrium adsorption capacity corresponds to the absorption capacity via the second-order kinetics, and this process follows Langmuir isotherm. To have a comparison with heterogeneous systems, optimum condition of the ultra-carbon heterogeneous system as a suitable process was evaluated (0. 015 g of ultra-carbon at pH = 4 and 750 rpm). Finally, advantages and disadvantages of the processes were compared in order to have an applicable system for scale up the laboratory process to a pilot system.

In this research, an electrochemical sensor based on carbon paste (CP) electrode modified by molecularly imprinted polymer (MIP) nanoparticles was developed for square wave voltammetric (SWV) determination of the diazinon (DZN) pesticide. The molecularly imprinted polymer particles and non-imprinted polymers (NIP) were synthesized by precipitation polymerization method with a molar ratio of 1: 6: 30 (target molecule: monomer: cross linker) and then used for modification of carbon paste electrode. The obtained results indicated that the electrode modifi ed by MIPs (MIP-CP) had much higher ability to DZN adsorption from sample solution than the NIP based sensor (NIP-CP). After optimization of the factors affecting the sensor response, the calibration curve was drawn under optimal conditions. The obtained curve was shown a linear relationship with DZN concentration in the range of 1. 50 × 10− 8 to 1. 25 × 10− 6 M (R2 = 0. 9905). The detection limit (LOD) of sensor was also obtained 5. 43 × 10− 9 M. The relative standard deviation (RSD %) for fi ve repeated measurements of 1. 25 × 10− 7 M DZN was 3. 79 %. The developed sensor was successfully used for determinations of DZN in well water sample with the recovery percentage in the range of 99. 06 – 99. 16 %.

A bat metaheuristic algorithm with the aid of artificial neural networks (ANN-BA) has been employed for the first time to optimize solvent-terminated dispersive liquid-liquid microextraction (ST-DLLME) as a fast, simple, and low cost technique for determination of Cu2+ ions in wastewater samples using p-sulfonatocalix[4]arene as a chelating agent. Toluene and methanol were used as extraction and disperser solvents, respectively. ANN-BA optimization has been carried out on four factors which was influenced on the extraction efficiency, such as extraction and solvent volumes, salt addition, and pH. Central composite design (CCD) as a comparative technique was employed for optimization of ST-DLLME efficiency. The ANN-BA optimization technique compared to CCD, was selected as a better model because of its higher value of extraction efficiency (about 7. 21%). Under ANN-BA optimal conditions, the limit of detection (S/N=3), limit of quantitation (S/N = 10), and linear range were 0. 12, 0. 35 and 0. 35-1000 μ g l-1, respectively. In this circumstance, the percentage recoveries for wastewater samples spiked with 0. 05, 0. 1 and 0. 2 mg l-1 of Cu2+ ions were in the acceptable range (92. 8 – 104. 5 %).

Today, air-lithium rechargeable batteries have wide applications in devices with energy saving capabilities. To increase performance and lifetime on these batteries, use of a catalyst and electrolyte are necessary. So, use of a catalyst from metal-transitional metals oxide based on carbon MnFe2O4/C with high surface in construction of battery cathode. To increase safety, lifetime and battery charging-discharging capacity, an ionic liquid of 1-ethyl-3-methylimidazolium tetrafluoroborate [C2mim][BF4] as electrolyte may be used. Properties of catalyst by using common techniques such as FTIR, TGA/DTG, XRD, and SEM were examined. Results showed that catalyst had porous, homogeneous structure, and particles size of 30 nm. Use of a catalyst at nanodimensions and ionic electrolyte with high conductivity caused to discharge capacity of battery to 2360 mAh g-1 and for battery without any catalyst to 815 mAh g-1 at current density of 0. 1 mA cm-1. At current density of 0. 2 mA cm-1 discharge capacities for battery with catalyst 710 mAh g-1 and without catalyst 535 mAh g-1 were obtained. Increase in discharge-charge cycles in presence of catalyst (>1000 times) compared with battery without catalyst (up to 3 times) represent performance of used catalyst. Due to ionic electrolyte stability, lifetime of battery about 2 times more than rather battery with common electrolyte. Decrease in difference between discharge and charge processes potential is one of the advantages of battery. Results showed that the use a catalyst of MnFe2O4/C caused to significantly increasing in battery discharge capacity.

In this research, β-Zeolite and amorphous silica alumina were synthesized for using in the support of the hydrocracking catalyst. In addition, Y-zeolite was used in the support of the prepared catalysts. Ni-Mo and Ni-W metals were impregnated on the extruded supports for preparation of final catalysts. Physical properties and acidity of the catalysts were characterized by BET and temperature programmed desorption (NH3-TPD) methods. Catalytic properties of the prepared samples were studied in hydrocracking process. The weight percent of zeolite content for preparation of the support, kind of active phase, and proper temperature of the process for producing middle distillate in vacuum gas oil hydrocracking were obtained by using a fixed bed continuous reactor and full-factorial experimental design. The results showed that the catalyst containing of 10 wt. % β-Zeolite, 30 wt. % Y-zeolite, and 5 wt. % Ni with 15 wt. % Mo, had the highest pore diameter and acidity. This catalyst at 400 ° C and operating pressure of 55 bar was the most selective catalyst to middle distillate products with respect to the others.

The antibiotics are widely used in the world and are released in water resource through various ways after usage. The presence of trace antibiotics in water or wastes could inactivate metabolic process of organisms alive in ecosystems. Therefore, detection and determination of their trace amount is very important. In this research, an electrochemical sensor based on molecularly imprinted polymers (MIP) and multiwall carbon nanotube (MWCNT) was designed and developed for detection and determination of MTN in real samples. For this purpose, the effect of several parameters such as incubation time of sensor in MTN solution and its pH, in addition influence of MIP and MWCNT amount for fabrication of the sensor are evaluated and optimized. Optimum conditions for preparation of sensor was obtained by 0. 105 g MIP, 0. 0033 g MWCNT, pH of 8. 0, and 26 min as incubation time of MTN on carbon paste electrode modified with MIP. Fabricated sensor was applied for separation and determination of MTN in real samples. The limit of determination of 55. 6 nM and linear calibration range of 50 – 1200 nM are obtained for determination of MTN by prepared sensor. The electrode modified by MIP and MWCNT was applied successfully for separation and determination of MTN at real samples.

In this research, waterborne polyurethane and hybrid of waterborne polyurethane/butyl acrylate(70/30, w/w%) based on N, N-Bis(2-hydroxyethyl)-2-aminoethane sulfonic acid sodium salt were synthesized via prepolymer mixing method and radical copolymerization. The molecular structure of the samples were characterized by FTIR spectroscopy. For studying the properties of the samples, thermal stability, morphology, tear resistance, abrasion resistance, and chemical resistance were investigated. The results showed that with incorporation of butyl acrylate to polyurethane backbone, thermal stability, tear resistance, abrasion resistance and chemical resistance were improved. Also, SEM images indicated that a morphology with good dispersion and fine particles was obtained. This is due to good compatibility between acrylate and polyurethane phases. According to these results, the hybrid sample is good candidate for coating application.

Nanotechnology and nanoscale materials have been fascinating subject of interest for the last decade. Nanocomposites are also considered as one of the branches of this new technology, and they are considered as an active research field. In the present work, poly(anthranilic acid)/Ag nanocomposite with various content of silver nanoparticles was synthesized via chemical oxidation method with antibacterial property. The structure of nanocomposites was then characterized and confirmed by FTIR, SEM, EDX, TEM, XRD, and TGA techniques. The results depict that the average particle size of the synthetic silver nanoparticles is about 20 nm. Using a variety of analysis methods, the synthesis of poly(anthranilic acid) nanocomposites and the formation of silver nanoparticles have been proven. The antibacterial property of the as-prepared nanocomposites was evaluated using disk diffusion method. According to this method, the inhibition zones for nanocomposites were obtained from 1. 6 upto 4. 5 mm. Results indicated that the poly(anthranilic acid) nanocomposites had acceptable antibacterial property. In summary, the obtained results demonstrated that the synthesized nanocomposites with antibacterial property can be used in medical applications as well as in wastewater treatment.

Environmental pollution by heavy metals and their fate in the environment have created major concerns. Recently, researchers have introduced a new method called diffusive gradients in thin films (DGT). The advantages of this method are in situ measurement of ions, especially in aqueous media. In this technique, patented materials were commonly used in making gels. The purpose of this study was replacing the two types of gels with different acrylamide-allylagarose compounds instead of the patented materials and investigate the effect of these materials on the diffusion coefficient of heavy metals in the diffusion layer of gels to be used in calculations related to the measurement of these elements. Also, the efficiency of DGT has been investigated in the solution of heavy metals. The results showed that with increasing pH, the ratio of swelling increased, although in the pH range between 4 and 9, no significant changes have observed in the ratio of swelling. The diffusion coefficients in inorganic solutions have been independent of ionic strength, although, with increasing ionic strength, diffusion coefficient in different repetitions had less error bar. The diffusion coefficients in different cations in two types of gel were 60-85% of their diffusion coefficients in water. By increasing the cross-linker factor, the diffusion coefficient have decreased due to the smaller pores in the gel. The amount of heavy metals measured by the DGT method had a linear correlation with the amount of cations in the solution (r2 = 0. 93-0. 99).