Journal of Applied Research in Chemistry
Year:2015 | Volume:9 | Issue:3|Papers Count:8

Polyaniline (PANI) is one of the most promising candidates for industrial application of conducting polymers. Due to its reversible electrochemical response during anodic oxidation and cathodic reduction, it is used as secondary batteries active material. In recent years, we see permanent efforts to improve performance of PANI batteries. So, many researches have been carried out for the improvement of its performance. In this work, PANI and PANI/G composite were chemically synthesized at 5°C. The characterizations were done by FTIR, Raman, BET, and SEM. Then PANI and PANI/G composite used as positive active material for PANI-Zn aqueous rechargeable battery. The prototype AA batteries were constructed and tested by constant current charge/discharge method between 1700 to 400 mV by 125 mAg-1 current density. It was found that PANI and graphite interaction was increased by composite formation between PANI and graphite while its surface area reduced compare to PANI. Then the PANI-G blend and composite were evaluated as battery cathode active material containing 5.0M ZnCl2 and 2.5M NH4Cl electrolyte at pH 4.0. The discharge curve of the PANI-Zn batteries containing composite active material showed lower internal resistance than PANI active material and maximum discharge capacity density and energy density increased up to 86.7 mAhg-1 and 101.44 Whkg-1, respectively (approximately 30% of theoretical value) compairing to 73.8 mAhg-1 and 71.58 Whkg-1 blended active materials. In addition, the PANI-Zn rechargeable battery with composite active material capacity reduced only 39% after 100 charge/discharge cycles. The mid-point voltages for two type of active material were 1170 mV and 970 mV, respectively. The PANI-Zn cell containing composite active material showed better electrical performances for use as a secondary system.

In this research, one-pot, four-component reaction of phthalic anhydride, hydrazine hydrate, aromatic aldehydes, and malononitrile has been described to afford pyrazolophthalazine derivatives in the presence of CuO nanoparticles in ethanol under reflux conditions. Using nontoxic and nano catalyst, simplified operational process, short reaction times, excellent yields, ease of purification of the products without using chromatographic separation, and environmentally benign reaction condition are the remarkable advantages of this synthetic strategy.

Thin layer chromatography silica gel is used in a special chemical-physical properties.Particle size distribution, specific surface area, pore volume, and pore diameter of this type of silica gel are within the specified range. After reviewing scientific and industrial related literature, documents and sources, finally the so-called slurry method was selected as our rout to prepare this kind of silica gel. According to our previous knowledge and experiences in the field of the silica, the silica gel product was prepared in laboratory scale in the Inorganic Chemistry Research Group. In this study initially, a well-known commercial silca gel sample named St.MN was characterized and consider as our evaluation criteria to evaluate our products. Then hydrogels were prepared in pH=9 via controlling temperature and reaction time in the range 80-85ºC and 12-15 minutes, respectively. In the next steps, aging and washing, the hydrogel was more processed.At this stage at 30 minutes after coagulation time, the hydrogels stirring and washing at room temperature via pH=4-5; then the resulting hydrogels, curing and silica gel product was prepared.The characterization results such as determination of adsorption capacity, pH of 10% aqueous suspension, bulk density, porosimetery (BET), elemental analysis (XRF), particle size analysis (PSA) show that two of the prepared products, STC07 & STC08 have an acceptable quality in comparison with dose of St.MN compound. the results obtained from qualifying tests for the TLC plates built with STC07 & STC08 samples were similar to dose of obtained for St.MN plate.

Separation and extraction of surfactants in water soluble mineral mixtures due to their high solubility is usually difficult. In this study, we have introduced a simple method for extraction of trace amounts of sodium dodecyl sulfate from aqueous solution of ammonium perchlorate by making foam, and then use of FT-IR spectroscopy for its qualitative measurement. In this procedure, sodium dodecyl sulfate is converted to ammonium dodecyl sulfate.

In this research, catalytic properties of ZrOCl2.8H2O in preparation of various bisarylmethylidene derivatives of 2, 2-dimethyl-1, 3-dioxane-5-one have been studied by using catalytic amounts of SDS and ZrOCl2.8H2O in the presence of water and diethylamine. Reactions take place at room temperature and high yields of the respective products are formed in short times. At the end, products precipitate spontaneously in the reaction mixtures. Thus, the products are separated easily by simple filtration and cumbersome chromatographic procedures are avoided.

In this study, Cu doped ZnO nanoparticles were synthesized in a homogeneous aqueous solution in presence of triton X-100 and sodium dodecyl sulfate as surfactant by combination coprecipitation and ultrasonic irradiation techniques. The particle size was controlled by the use of surfactant. As-synthesized powders were characterized for morphology of structural and particle size by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The XRD measurement reveals that the prepared nanoparticles have different particle sizes from 18 to 32 nm without changing a hexagonal wurtzite structure. The results showed that a well crystalline hexagonal structure of copper doped ZnO phase was formed through precipitation precursors at pH value of 12. The pH was adjusted by the use of sodium hydroxide solution. All results indicated significant influence of Cu doping on relevant structural properties of ZnO.

In this research an electrochemical sensor based on carbon paste (CP) electrode modified by molecularly imprinted polymer (MIP) was prepared for determining of the diazepam (DZ) drug. Molecularly imprinted polymer microparticles were synthesized by precipitation polymerization method and then were used as identification element in construction of the sensor.Also for comparison, the non-imprinted polymer (NIP) particles were synthesized in a similar manner but in absence of diazepam molecules. SEM images of obtained polymers showed that the MIP particles have dimensions in the range of 100-300 nm. Cyclic voltammetry (CV) and square wave voltammetry (SWV) methods were applied to study the electrochemical behavior and quantitative measurements. The obtained results showed that the MIP-CP electrode have much higher adsorption ability to diazepam than the NIP-CP electrode. The effect of some parameters affecting on the sensor response, such as electrode composition, extraction conditions, and electrochemical measurements conditions were studied and then calibration curve was drawn.Peak current showed a linear relationship with diazepam concentration in range of 4.0 × 10-8 to 8.0 × 10-6 mol L-1 and the limit of detection was also equal to 1.94 × 10-8mol L-1. The relative standard deviation for five measurement of 5.0 × 10-7 mol L-1 diazepam solution was obtained 3.48%. The developed sensor has been successfully used for determinations of diazepam in human blood serum samples.

In this work, an efficient and simple synthetic method for preparation of 2, 4, 5-trisubstituted imidazoles has been designed by three-components cyclocondensation of benzil, a variety of aldehydes and ammonium acetate in the presence of L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate supported on silica gel as a catalyst under solvent free condition. Moreover, this catalyst has been used for the one-pot, four-component synthesis of 1, 2, 4, 5-tetrasubstituted imidazoles. These synthetic procedures are very simple and affording good to excellent yields of imidazoles derivatives. The key advantages of this process are the elimination of organic solvents, use of nonmetallic, and environmentally benign catalyst and purification of products by non-chromatographic method.