Journal of Applied Research in Chemistry
Year:2020 | Volume:14 | Issue:3|Papers Count:12

Levofloxacin, a chiral carboxycinolone, is a synthetic antibiotic with a broad spectrum effects. One of the challenges in the synthesis of this compound is efficient catalytic synthesis of their key structural intermediates (Q-acid). Several methods have been reported for the synthesis of this active pharmaceutical ingredient in which toxic and expensive solvents have been used. In this study, focusing on the last step in the synthesis of levofloxacin using commercial Q-acid, an attempt was made using catalysts with Lewis acid character and the use of safe solvents. First, magnetic montmorillonite (MM) was synthesized and purified. The reaction of methylpiperazine with Q-acid intermediate for levofloxacin synthesis was also performed under different conditions. The best results were obtained using methylpiperazine and Q-acid with a molar ratio of 1. 2: 1 in the presence of catalytic amounts of MM in ethanol solvent (95%) at 70 ° C for 8 h. At the end of the reaction, MM was recovered using a magnet and a simple filtration and dried for 2 h at 100° C for activation and used for 5 consecutive reactions to evaluate levofloxacin synthesis without significant decrease in efficiency. In total, taking into account factors such as raw material consumption, solvent type and simple recycling conditions, operating temperature and energy consumption, type and amount of catalyst and its recovery, solvent and catalyst biocompatibility, production of levofloxacin hemihydrate in the method presented in this study, are associated with lower cost, and its production at increased scales will have good economic benefits.

In this study, Organic-inorganic iron-phosphonate nano-catalyst was prepared by using Iron (Ι Ι ) chloride with a basic solution of diethylene triamine-penta (methylene phosphonate). The size of nanoparticles was controlled by cetyl tri-methyel ammonium bromide (CTAB) as a surfactant. The structure of the synthesized Fe@DTPMP nanomaterials was fully characterized by using different methods such as FTIR, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), vibrating sample magnetometry (VSM), and Energy-dispersive X-ray spectroscopy (EDS). The SEM analyze confirmed a hollow spherical micromorphology with well-defined porosity. In the presence of surfactant, the nanoparticles have a spherical structure and particle size of about 20-30 nm. The magnetization of synthesized nanoparticles in a field with a strength of 15KOe is about 5 emu/g. The TGA analysis demonstrates significant catalyst stability against heat, so that there is no specific failure at temperatures up to 300 ° C. The antibacterial test of this nanoparticle showed that these materials prevented the growth of the gram-negative and positive bacteria (Staphylococcus aureus, colic Oshirshiyya). These nanoparticles created a halo 14-16 mm in diameter in their surroundings.

In this study, an ultrasound-assisted liquid-liquid microextraction (UALLME) method based on the deep eutectic solvent (DES) was developed, for the first time, for extraction of carvedilol from plasma samples before analysis by spectrofluorimetry method. The DES was prepared by mixing the appropriate amount of the choline chloride and phenol in the ratio of 1: 2. The prepared DES was used without any further purification for UALLME of carvedilol from plasma samples. The effects of some critical parameters including DES components ratio, salt addition, and kind of emulsifying solvent were studied and optimized by a one-at-a-time approach. A central composite design was used for efficient optimization of the rest of the main variables in the extraction procedure including pH, the volume of DES, the volume of THF, and ultrasonication time. The method showed excellent linearity (R = 0. 9993) in the range of 15-1000 ng ml 2-1, under the optimal conditions. The extraction recovery of 93. 2 % was obtained, and LOD and LOQ values were found 3. 3 ng ml, respectively. The method was successfully applied for the determination of the drug in spiked human plasma samples where it gave relative recoveries of 91. 7 % and 93. 2 %.

Zeolites are crystalline and hydrated aluminosilicates from earth alkali and alkaline metals, which are used to the removal and separation of pharmaceutical pollutants due to their chemical structure and proper surface area. In the present study, first, natural zeolite was powdered by ball mill, and after that, it was modified by a cationic surfactant of the Hexadecyltrimethylammonium bromide. The modified zeolite was investigated by XRF, FTIR, SEM, BET, and XRD techniques. According to BET results, surface area, average pore diameter, and pore volume of the sample were 12 m /g, respectively. Additionally, the efficiency of the sample was studied for removal of diclofenac from the aqueous medium. The results showed that environmental factors, such as adsorbent dose, contact time, pH, temperature, and diclofenac concentration were effective in removal percentage. In addition, the kinetic data were described better with pseudo-second-order kinetic model, also, the equilibrium data for adsorption of diclofenac were fitted well by Langmuir isotherm and the maximum adsorption capacity was 34. 364 mg/g at 298 K approximately.

Preparation, characterization, and investigation of the biodegradability behavior of the new generation of biodegradable water-based polyurethanes on the developing of environmentally friendly materials have been studied in this research. This series of biodegradable polyurethanes were made based on polyols from renewable sources such as castor oil, with polyethylene glycol, using suitable diisocyanate combinations. In this study, in particular, the effects of polyethylene glycol on biodegradability and the properties of these polymers were investigated. Synthesized polymers were characterized using the HNMR and Fourier transforms infrared (FTIR) spectroscopy. Particle size measurements were performed using dynamic light scattering (DLS). The biodegradability of prepared PUDs was assessed and confirmed using water uptake, hydrolytic and enzymatic degradation in phosphate buffer saline (PBS) by using lipase enzyme and by the evaluation of contact angle and atomic force microscopy images. The results of the investigation showed that with the addition of natural and degradable components in the polymer backbone and adjusting the hydrophilic properties of soft segments, useful polyurethanes with desirable degradability properties could be obtained.

Due to the harmful environmental effects caused by the petroleum based lubricants, their replacement with environmental friendly oils has been considered. The aim of this study is to prepare a biological lubricant from Sesame oil during chemical modification using the trans-esterification reaction and addition of appropriate antioxidant materials. By creating a group of esters on trans position, a product with good lubrication, high viscosity index, high flash point, low pour point, and environmental friendly properties including high degradability and low toxicity were obtained. In the first step, by using an (or of) acetylchloride catalyst, the triglyceride molecules of the Sesame oil were methanolized in a reaction of methanol at 100 ° C in a reflux system. In the next step, the obtained methyl ester in presence of lipase enzyme (as catalyst) by reaction of trimethylolpropane (TMP) was taken at 50 ° C for 24 hours. Then, different parameters (molar ratio of alcohol to oil, temperature, and enzyme concentration) were evaluated and the best conditions for esterification of Sesame methyl ester with TMP were obtained. Also, some of the physicochemical properties of the lubricants were investigated by using the differential scanning calorimetry (DSC) and viscometry.

Parabens are widely used as preservatives in pharmaceuticals, food, and personal care products. Solid phase extraction (SPE) is one of the most frequently used methods for monitoring parabens in aqueous samples. However, SPE is a costly and time consuming method. In this study, the application of piecewise direct standardization (PDS) method for transfer of direct calibration of gas chromatography-mass spectrometry (GC-MS) data to SPE-based calibration and quantification of methyl, ethyl, propyl, and butyl parben derivatives in aqueous environmental samples has been evaluated. In this method, at first, a multivariate model is constructed using different chromatographic regions based on only two subsets of direct and extracted calibration data, and then a transformation matrix is obtained, which in the next step it can correct all direct calibration samples to be matched with SPEbased data. Modeling validation was confirmed using altrernating trilinear decomposition (ATLD) method, and the recovery values were 81-106% and the mean relative prediction error was 2. 1-6. 4% for validation samples. Finally, modified direct calibration samples were used to detect and predict pollutants (at low µ g/l values) in several real water samples.

In recent years, significant advances have been made in the use of biomedical polymers as targeted carriers for the release of drugs, proteins, and growth factors. Vanadium (V) nanocomposite hydrogels were prepared in this study due to the formation of vanadium nanoparticles inside the swollen CMC hydrogels. The formation of vanadium (V) nanoparticles in hydrogels has been studied using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction patterns (XRD), scanning electron microscopy (SEM) experimental techniques. The XRD patterns analysis confirmed the formation of vanadium nanoparticles in a hydrogel matrix, and scanning electron microscopy micrographs also showed that the size of the nanoparticles was from 22 to 74 nm in the hydrogel matrix. The swelling behavior of nanocomposite hydrogels was studied at pH of 2. 1 and 7. 4. Hydrogels have shown better water absorption in less pH. Fourier transform infrared spectroscopy indicates the interaction between polysaccharides and the samples taken from the drug indicate that the drug-loaded peaks were loaded appropriately. With the release of drug from nanocomposite and pure hydrogel hydrogels, it was observed that its release rate in nanocomposite hydrogels was lower and the amount of its release decreased with increasing percentage of nanoparticles. In the cytotoxicity test after 24 h, the cell viability was in the range of 74. 35%-96. 05% (compared with the control sample, which was 100%). In the hydrogel nanocomposite sample containing insulin had the lowest cell viability of insulin 31. 25 μ g/ml after 24 h and it had the highest cell viability at 1000 (μ g/ml) concentration with 25. 7% cell cytotoxicity compared to the control group.

In this study, the degradation of 4-nitrophenol in aqueous environments was studied by Electro Fenton and Electro Persulphate in electrochemical batch reactor equipped with four iron electrodes and a direct power source. The results showed that the removal of 4nitrophenole in Electro-Persulphate and electro Fentone were 99. 2% and 94% at optimum operation condition including operational pH at 3, the initial concentration of 4-nitrophenol at 100 mg / l, hydrogen peroxide and persulphate at 0. 5 mM, with the density of 0. 1 A/dm and 60 min of reaction. The research results showed that the processes of electro-persulfate and electro-fenton had the same elimination efficiency in acidic media for 4-nitrophenol removal and, in general the combination of electrochemical with persulfate and hydrogen peroxide for electrical production of iron and activation of persulfate and hydrogen peroxide had more ability compared to separate use. The removal percent of COD in real wastewater samples with the initial COD of 5000 mg/l were 82 and 86% in ElectroFenton and Electro-persulfate processes, respectively.

The polymer matrix in the organic-mineral hybrid nanocomposites is flexible and lightweight, and inorganic nanoparticles are responsible for high thermal stability and improved their mechanical properties. In this study, Methyl Methacrylate-Butyl Acrylate copolymer (BAMMA) was synthesized by conventional emulsion polymerization with conversion percentage of 96. 15%. In order to synthesize nanocomposite, nanoparticles of silver, titanium dioxide, iron oxide (Fe3O4), unmodified silica, and modified silica with 3-(tri-methoxysilyl) propyl methacrylate (MPS) and dichloromethyl vinylsilane (DMVS) modifiers were used. Based on the results of the thermal gravimetric analysis, nanocomposite prepared from BA-MMA copolymercontaining 0. 3 g of modified silica with 0. 183 milliliters of chloro-methyl vinyl-silane modifier showed the highest thermal stability. Mechanicl resistance of this sample in terms of the scratch was investigated by nano-scratch instrument and the results showed that, the coating with the lower friction coefficient 0. 724 and lower scratch coefficient 0. 267 12  N has high scratch resistance. Chemical structure of synthesized compounds were confirmed by Fourier transform infrared spectroscopy.

In this study, a novel vortex-assisted liquid-liquid microextraction based on solidification of a floating organic droplet (VALLME-SFO) was proposed for the microextraction of Pd(II) before its determination by flame atomic absorption spectrometry. A central composite design was used to find the optimum conditions for the preconcentration procedure through response surface methodology. Five variables, including type and volume of extraction solvent, solution pH, ligand concentration, and duration of vortex exposure, were investigated. Under optimum conditions, pH=7, 1. 5 ml of 2-mercaptobenzimidazole 3 mM, 40 μ l of 1-Undecanol, a detection, and 5 min vortex, detection limit 3. 3 μ g/l and quantitation limit 11 μ g/l with the relative standard deviation 2. 4% was achieved. The recoveries of the analytes in Karadj river samples were in the range of 96– 104 %. Analysis of variance (ANOVA) was used to show lack of interferences in the matrix of real samples.

In present work, the gas phase reforming of normal heptane was used to study the catalytic activity of micro/mesoporous composites. The influence of the structures of these catalysts on the normal heptane conversion and the selectivity to various products including multi and mono branched isomers and cracking products was studied. Various characterization techniques, i. e., X-ray diffraction (XRD), X-ray florescence (XRF), Fourier transform infrared (FTIR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), thermogravimetry and differential thermal analyzer (TGA/DTA), and nitrogen adsorption-desorption measurements were used for characterization of the catalysts. The catalytic activity and stability in normal heptane reforming for platinated composite materials consisting of HMS mesopore section (hexagonal mesoporous silica) and microspore section of series A zeolites including 3A, 4A, and 5A, were very close to each other. However, the results show that the selectivity toward the formation of isomers is remarkably high for Pt/4A-HMS composite catalyst. The results show that the effective parameter on catalytic performance is the aluminum amount (or Si/Al ratio) in the structure of the prepared catalysts.