Journal of Applied Research in Chemistry
Year:2019 | Volume:13 | Issue:2 |Papers Count:15

Conducting polymers represent a class of materials that possess unique combination of electrical conductivity, processability, and mechanical properties. One of the most important applications of these materials is electromagnetic interference shielding which are receiving increasing attention by progress of technology and increment in the amount of electromagnetic waves sources. In the present study, attempts have been made to prepare improved electromagnetic interference shielding (EMI-SE) material of flexible composite films based on thermoplastic urethane (TPU) and graphene nanosheets. For this purpose, the prepared graphene oxide using Hummer’ s method has been thermally reduced. Then the surface of the graphene was grafted with polar and long molecules of 2-aminoethyl methacrylate (AEMA) and denoted as functionalized graphene nanosheets (FGN). Then the nanocomposites with various loadings of FGN were fabricated by solution mixing. The increased compatibility between TPU segments and FGN due to graphene modification leads to increase in electrical conductivity. Moreover, the intensified interactions and improved dispersion state of the FGN increase viscous motions and energy dissipation which leads to higher EMI SE. Results showed that the TPU based nanocomposite containing only 5 vol. % of FGN attenuate electromagnetic wave energy up to 99. 8%.

An efficient one-pot method for the synthesis of fused 2-imino-hexahydroquinazolin-5(6H)-one derivatives with pharmaceutical potential from cyclocondensation of dimedone, aldehydes, and guanidinium carbonate under catalyst-free and environmentally friendly conditions is described. The present method displays several key advantages such as one-pot and catalystfree conditions, high yields, short reaction times, and simple product purification procedure, i. e., simple recrystallization from ethanol. It should be noted that the obtained results also indicated that cyclocondensation of dimedone and aldehydes using guanidinium chloride in presence of sodium hydrogen carbonate as base led to synthesis of fused 2-imino-hexahydroquinazolin-5(6H)-one derivatives with pharmaceutical potential with high yields, and short reaction times. The obtained results also indicated that cyclocondensation of dimedone and aldehydes in presence of guanidinium chloride as a promoter led to synthesis of hexahydroxanthene derivatives with pharmaceutical potential with high yields and short reaction times. In addition, the results of the antibacterial test for some of the hexahydroquinazolin and hexahydroxanthene compounds showed that these compounds had a good activity against a gram-negative bacteria such as Escherichia coli and had the ability to adequately inhibit the growth of bacteria.

In this research, nanoporous silica SBA-15 was modified with 3-[2-(2-amino ethyl amino) ethyl amino] propyl trimethoxysilan. Then, a fluorene derivative was grafted on inner surface and triamine fluorene functionalized nanoporous SBA-15 was synthesized. The resultant material was characterized by X-ray diffraction, N2 adsorption-desorption measurements, infrared spectroscopy for investigation of porosity and functional groups of mesoporous silica. This material was used for extraction of silver in aqua solution. Flame atomic absorption spectrometry was used to determine the ions concentration in the eluted solution. The effect of several variables, such as amount of adsorbent, contact time, pH, metal concentration, and presence of other metals in the medium have been studied. Silver ions was completely extracted using 10 mg of adsorbent after 10 minutes. The experimental data were analyzed using the Langmuir and Freundlich adsorption models and the data was found to fit well into the Langmuir model. The maximum adsorbent capacity was determined 357. 14 (± 1. 8) μ g silver per each milligram of functionalized SBA-15 adsorbent. Finally, the adsorbent was used successfully for extraction of silver from photography solution.

Nowadays, the use of photocatalysts in the removal of water pollutants is very much considered. Meanwhile, titanium dioxide with unique properties has a special place. The functional drawbacks of photocatalytic nanoparticles have led to the production and application of their various geometric structures. Synthesis of fibers is performed as a single-dimensional structure in a variety of methods. In this study, TiO2 fibers were synthesized using natural silk. Silk fibers, with good surface properties, uniformity of size and easy removal, are the perfect choice for producing nano-fibers. The synthesized structure was evaluated by analyzing XRD, SEM, FTIR, and BET. The results showed that after calcination at 450° C, there are only two anatase and rutile phases in the fibers. In fact, the sample was removed entirely from silk by heating and other analyzes also confirmed this. The photocatalytic performance of the synthesized fiber was analyzed by removing methyl orange. After 210 minutes, 94% of the dye was degraded by TiO2 fibers.

In this study, hexadecane-melamine formaldehyde microcapsule (HD@MF) was synthesized as a phase change material (PCM) using in-situ polymerization technique. The chemical structure of microcapsule was investigated by Fourier transform infrared spectroscopy (FTIR). Optical microscopy and scanning electron microscopy (SEM) were also used to study the size and morphology of microcapsules. HD@MF microcapsules were printed on cotton fabric with a thickness of 120 μ m using acrylic resin. In order to investigate the effect of life cycle on chemical properties and physical structure, the printed cotton fabric was subjected to warm-up and cooling down cycle 800 times, and its chemical-functional properties as well as morphology were evaluated using ATR-FTIR spectroscopy and scanning electron microscopy (SEM), respectively. The obtained results showed that these microcapsules were affected by the warmup and cooling down cycle, and lose their properties. In fact, after repeating the heating cycle and cooling frequently (800 times), the microcapsule's shell is broken and hexadecane is released.

Zeolite N. P. (Nano-Particles)/GO and zeolite N. P. /HPC/GO composites were synthesized and investigated as a heavy metal nanosorbent in the aquatic media. The Fourier-transform infrared spectroscopy (FT-IR) spectrum confirmed the expected pattern and the field-emission scanning electron microscopy (SEM) images revealed the formation of zeolite nanoparticles and graphene oxide layer structure. The presence of the expected elements was confirmed by the energy dispersive X-ray (EDS) analysis and the X-ray diffraction (XRD) pattern confirmed the formation of zeolite and graphene oxide by the crystalline structure. The nanosorbents used to remove lead (II) and cadmium ions in the aquatic media and the effective parameters were investigated and optimized for the removal process. Optimal values of zeolite N. P. /GO composite for Pb2+ and Cd2+ ions are: pH = 7 and 4 corresponding to contact times = 10 and 15 minutes, respectively, also the optimal amount of sorbent for both ions is 0. 01g in the optimum temperature 25 ° C. The optimum contact time, temperature and sorbent dosage of zeolite N. P. /HPC/GO for both ions were obtained 30 minutes, 25 ° C and 0. 005g, respectively. The optimum pH values of both ions were as used for the previous nanosorbent. The interference ions did not significantly affect the removal efficiency of both ions by the synthesized nanosorbents. The nanosorbents showed effective removal efficiency in three samples of agricultural waters in south Tehran. The results showed that the data follow both Langmuir and Freundlich isotherms.

Magnetic polymers were used as suitable stabilizers for the synthesis of various nanoparticles. The synthesized nanoparticles with this method, can be very resistant against agglomeration and resulting in better performance in a variety of applications. In this research, magnetic polymer nanocomposites of magnetite-chitosan (Fe3O4-CS) were prepared through co-precipitation of Fe2+ and Fe3+ ions in an aqueous solution of chitosan. Then Ag nanoparticles immobilized on this nanocomposite by chemical reducing AgNO3 with NaBH4. The nanostructures have been characterized by X-ray powder diffraction (XRD), scanning electronmicroscopy (SEM), and vibrating sample magnetometry (VSM) techniques. Then, antibacterial activities of supported Ag nanoparticles were investigated for a variety of microorganisms such as Gram-positive, Gram-negative bacteria, and fungal strains.

In this paper, we have reported the synthesis and characterization of new magnetic bionanocatalyst based on chitosan and investigated their catalytic activity in the C-C bond formation reaction. To increase the stability of chitosan, chitosan oxide and starch oxide biopolymers were used for the covalent linking between chitosan chains and formation of Schiff base between amine groups of chitosan and carbonyl functional groups of chitosan oxide and starch oxide. Then, the imine bonds were reduced to prevent their possible hydrolysis. In order to catalyst simple separation of reaction mixture, biopolymer support was magnetized with iron oxide nanoparticle addition. Then, palladium chloride was immobilized on this support and the efficiency of the obtained nanocatalyst was investigated in the Suzuki coupling reaction. The biphenyl products were synthesized under optimized at the short reaction times with excellent yields in water as green solvent. After the reaction cycle, these catalysts were recovered by using a magnetic field and directly reused for several times without significant loss of its activity.

In this research, a new derivative of dimer calix[4]arene has been designed and synthesized and its molecular structure has been investigated by IR, 1HNMR, 13CNMR, Mass spectroscopy, and Elemental analyses. These studies show that this dimer calix[4]arene is a bridgeless dimer and has been synthesized from head-to-head coupling of two calix[4]monoquinone unites; two cavities of this dimer are arranged in an opposed manner and these unites to be able to host distinct for small biomolecules guests, one in each cavity as an artificial receptor, therefore a number of small biomolecules have been selected for recognition in this study and the Ultra Violet spectrophotometric technique was used to evaluate sensing ability of interaction between dimer calix[4]quinone and these guests. The results obtained from titration of visible and ultraviolet spectroscopy and association constant (KA) of calix dimer synthesized with each one of the selected guests, revealed that dimer calix[4]quinone as an artificial receptor is capable of complexing only with the N-Boc-Alanine.

In this research, the sumac plant was collected from Ahar region trees in the East Azarbaijan province, dried in a shade, was milled and finally extracted by three methods: macerate, soxhlet, and ultrasonic treatment. The active ingredient of Protocatechuic acid and its percentage were determined by High-Performance Liquid Chromatography (HPLC). In the next step, vinyl derivative of Protocatechuic acid was synthesized and polymerization reaction with acrylic acid, methacrylic acid, and styrene monomers in the presence of AIBN was performed, and its nanocopolymers were prepared with a freeze dryer device and the structure of the products with FTIR, 13CNMR, 1HNMR, XRD, DSC, TGA and SEM spectra checked and determined. The controlled release of Protocatechuic acid from copolymers was evaluated separately in both simulated stomach conditions and intestinal conditions in buffered media pH=1 and pH = 7. 4. In the final part of the work, the antioxidant property of methanolic extract, total phenolic, and flavonoid content was measured.

Chiral alcohols have wide applications as building blocks for pharmaceuticals, pesticides, pheromones, flavors, fragrances, pigment and so on. Stereo-selective reduction of prochiral ketones by biologic methods is one the most effective and simple way for synthesizing alcohols. Using different plants as biocatalysts is one of these suitable methods. In this study, enantioselective reduction of carbonyl group was done by Iranian Daucus carota root plant cells and the corresponding chiral alcohols were synthesized. Aryl-alcohols with yield about 90% were obtained. The Fourier-Transform Infrared (FTIR) analysis confirmed the conversion of carbonyl groups to hydroxyl groups. The products were characterized by comparison of their melting points and Proton Nuclear Magnetic Resonance (1H-NMR) data with those reported. Polarimetry was used to determine the optical rotation of the molecules. The advantages of this method are mild conditions, high stereo-selective, the application of a wide range of substrates, easy recycling of products, disposal of biological materials, and high yields. In previous studies, couple biocatalyst contain plants and enzymes were used as reduction agent of ketones to secondary alcohols. In this research, Iranian Daucus carota root plant cells without any enzymes has been used for this purpose for the first time.

ZnS: CuS nanocomposite flexible thin films have been prepared by simple and low cost chemical bath deposition (CBD). Additionally, the effect of dipping time of the ZnS thin films into the copper chloride solution on structural, morphological, optical, and photocatalitic properties of the ZnS: CuS films have been investigated by XRD, FE-SEM, TEM, and UV-vis spectroscopy. XRD and TEM results confirmed formation of the flexible ZnS: CuS nanocomposite films which consist of nanocrystals with less than 10 nm in diameter. FE-SEM images indicate that ZnS: CuS thin films consist of high compactness particles with good adhesion to the flexible substrates. Energy band gap of the films were decreased by increasing amount of Cu in the films which it could be related to the formation of the CuS phase. The prepared ZnS: CuS nanocomposite thin films showed a photocatalytic activity in degradation of Rhodamin B dyes (water pollutant). By increasing amount of Cu in the films and exposure time in the visible light, degradation percentage of the Rhodamine B dyes were increased because of the decrease in recombination of the electron – hole pairs. During investigation of the photocatalytic activity of the layers, due to strong adhesion to the substrate, it was not necessary to homogenize the solution and centrifuge for extracting nanoparticles from the solution.