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641.
Synthesis,characterization, metal sorption,and biological activities of organosoluble and thermally stable azoxanthone‐based polyester 下载免费PDF全文
The aim of this work was to develop functionalized polyxanthones, poly(azoxanthone‐ester)s (PAXEs), with biological activities and heavy metal sorption abilities. For this purpose, at first, new xanthone‐based diol moiety was synthesized and then used for polymerization with commercial dicarboxylic acids via polycondensation reaction by Vilsmeier adducts. The monomer and all polymers were characterized by Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) spectroscopies, and the physical properties of these PAXEs including solution viscosity, solubility properties, thermal stability, and thermal behavior were studied. The prepared polyesters showed excellent thermal stability and good solubility in polar aprotic solvents. In addition, evaluation of antioxidant activity of the PAXEs by 2,2‐diphenyl‐1‐picrylhydrazyl assay revealed that synthesized polymers have higher antioxidant activity than xanthone nucleus. Also, evaluation of the antibacterial activities of the diol monomer and polymer showed good antibacterial activity against some bacterial strains (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa). The results showed that these PAXEs can be used in pharmaceutical and food industry (food packaging). Furthermore, these functionalized polyesters were utilized for extraction of environmentally harmful metal cations such as Cr (VI), Co (II), Ni (II), Cu (II), Pb (II), and Cd (II) from aqueous solutions. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
642.
The electrocatalytic oxidation of sulfite has been studied at a stable electroactive thin film of copper‐cobalt hexacyanoferrate (CuCoHCF) hybrid electrodeposited on a carbon paste electrode (ECMCPE). A linear range of 5 μM to 5 mM of sulfite, with an experimental detection limit of 1 μM, was obtained using the cyclic voltammetric method. The oxidation of sulfite showed no significant fouling effect on the modified electrode surface at sulfite concentrations below 5 mM. The proposed modified electrode exhibited several attractive features, including simple preparation, fast response, good stability and repeatability, and could be applied to sulfite determination in real samples. 相似文献
643.
Babak Mokhtarani Ali Sharifi Hamid Reza Mortaheb Mojtaba Mirzaei Morteza Mafi Fatemeh Sadeghian 《The Journal of chemical thermodynamics》2009,41(3):323-329
Densities and viscosities of two pyridinium-based ionic liquids, 1-butylpyridinium tetrafluoroborate [BuPy][BF4] and 1-octylpyridinium tetrafluoroborate [OcPy][BF4], and their binaries with water at atmospheric pressure and temperatures from (283.15 to 348.15) K were determined. The densities and viscosities of pure ionic liquids were correlated successfully by empirical equations. The Vogel–Fulcher–Tammann equations can fit the experimental viscosities for pure and binary of both IL systems. Excess molar volume and viscosity deviation were calculated for the binaries. The excess molar volumes have positive deviation from ideal solution while the viscosity deviations have negative values. 相似文献
644.
Mojtaba Shamsipur Nazir Fattahi Marzieh Sadeghi Meghdad Pirsaheb 《Journal of the Iranian Chemical Society》2014,11(1):249-256
A solid-phase extraction coupled with dispersive liquid–liquid microextraction (DLLME) method followed by graphite furnace atomic absorption spectrometry (GFAAS) was developed for the extraction, preconcentration, and determination of ultra trace amounts of lead in water samples. Variables affecting the performance of both steps were thoroughly investigated. Under optimized conditions, 100 mL of lead solution were first concentrated using a solid phase sorbent. The extracts were collected in 1.50 mL of THF and 18 μL of carbon tetrachloride was dissolved in the collecting solvent. Then 5.0 mL pure water was injected rapidly into the mixture of THF and carbon tetrachloride for DLLME, followed by GFAAS determination of lead. The analytical figures of merit of method developed were determined. With an enrichment factor of 1,800, a linear calibration of 3–60 ng L?1 and a limit of detection of 1.0 ng L?1 were obtained. The relative standard deviation for seven replicate measurements of 30 ng L?1 of lead was 5.2 %. The relative recoveries of lead in mineral, tap, well, and river water samples at spiking level of 10 and 20 ng L?1 are in the range 94–106 %. 相似文献
645.
Mojtaba Shamsipur Mahmoud Roushani Seied M. Pourmortazavi Nahid Shahabadi 《Central European Journal of Chemistry》2014,12(10):1091-1099
Electrocatalytic oxidation of sulfide ion on a glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNTs) and a copper (II) complex was investigated. The Cu(II) complex was used due to the reversibility of the Cu(II)/Cu(III) redox couple. The MWCNTs are evaluated as a transducer, stabilizer and immobilization matrix for the construction of amperometric sensor based on Cu(II) complex adsorbed on MWCNTs immobilized on the surface of GCE. The modified GCE was applied to the selective amperometric detection of sulfide at a potential of 0.47 V (vs. Ag/AgCl) at pH 8.0. The calibration graph was linear in the concentration range of 5 µM–400 µM; while the limit of detection was 1.2 µM, the sensitivity was 34 nA µM?1. The interference effects of SO3 2?, SO4 2?, S2O3 2?, S4O6 2?, Cysteine, and Cystein were negligible at the concentration ratios more than 40 times. The modified electrode is more stable with time and more easily restorable than unmodified electrode surface. Also, modified electrode permits detection of sulfide ion by its oxidation at lower anodic potentials. 相似文献
646.
Thiol‐functionalized fructose‐derived nanoporous carbon as a support for gold nanoparticles and its application for aerobic oxidation of alcohols in water 下载免费PDF全文
Gold nanoparticles supported on thiol‐functionalized fructose‐derived nanoporous carbon (AuNPs@thiol‐Fru‐d‐NPS) were found to be a simple bench‐top, biocompatible, recyclable and selective catalytic system for the aerobic oxidation of various types of alcohols into their corresponding aldehydes and ketones at room temperature under the environmentally friendly conditions with excellent yields. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
647.
Electrochemical Behavior of Glucose Oxidase Immobilized on Pd‐Nanoparticles Decorated Ionic Liquid Derived Fibrillated Mesoporous Carbon 下载免费PDF全文
Behzad Haghighi Babak Karimi Mojtaba Tavahodi Hesam Behzadneia 《Electroanalysis》2014,26(9):2010-2016
Pd nanoparticles with an average diameter of 5 nm were decorated on the surface of ionic liquid derived fibrillated mesoporous carbon (IFMC) to prepare a novel nano‐hybrid material (Pd@IFMC). Thereafter, glucose oxidase was immobilized on Pd@IFMC modified glassy carbon electrode to fabricate an enzymatic glucose biosensor. A pair of well‐defined redox peaks was recorded for direct electron transfer of the immobilized glucose oxidase at the formal potential of ? 0.418 V with a peak to peak separation of 25 mV. Electron transfer rate constant of was calculated to be 14.6 s?1. The response of fabricated biosensor was linear towards glucose concentration. 相似文献
648.
A selective and sensitive stripping voltammetric method for the determination of trace amounts of copper(II) with a recently synthesized naphthol-derivative Schiff's base (2,2'-[1,2-ethanediylbis(nitriloethylidyne)]bis(1-naphthalene)) is presented. The method is based on adsorptive accumulation of the resulting copper-Schiff's base complex on a hanging mercury drop electrode, followed by the stripping voltammetric measurement at the reduction current of adsorbed complex at -0.15 V (vs. Ag/AgCl). The optimal conditions for the stripping analysis of copper include pH 5.5 to 6.5, 8 microM Schiff's base and an accumulation potential of -0.05 V (vs. Ag/AgCI). The peak current is linearly proportional to the copper concentration over a range 2.3-50.8 ng ml(-1) with a limit of detection of 1.9 ng ml(-1). The accumulation time and RSD are 90 s and (3.2-3.5)%, respectively. The method was applied to the determination of copper in some analytical grade salts, tap water, human serum and sheep's liver. 相似文献
649.
Melamine trisulfunic acid is employed as a recyclable catalyst for the condensation reaction of aromatic aldehydes with 3‐methyl‐l‐phenyl‐2‐pyrazolin‐5‐one. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4′‐(arylmethylene)‐bis‐(3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐ols) in 80‐96% yields. 相似文献
650.
A new and convenient method for the synthesis of biscoumarins based on the condensation of 4‐hydroxycoumarin and aromatic aldehydes in the presence of Mohr's salt hexahydrate (ferrous ammonium sulfate hexahydrate) as a novel catalyst on water is developed. This method has advantages such as the use of inexpensive and available reagent, avoidance of organic solvents, short reaction times, and high product yields. 相似文献