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1.
Abdülhadi Baykal Yüksel Köseoğlu Mehmet Şenel 《Central European Journal of Chemistry》2007,5(1):169-176
Heating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size
estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements
confirm a typical Mn2+signal with a highly resolved hyperfine structure.
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2.
Andris Zicmanis Galina Vavilina Svetlana Drozdova Peteris Mekss Maris Klavins 《Central European Journal of Chemistry》2007,5(1):156-168
Alkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of
ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent
of the presence of small amounts of protic solvents or water.
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3.
Melinda Fekete Mercedesz Töröncsi Lajos Novak 《Central European Journal of Chemistry》2008,6(1):33-37
Palladium-catalyzed amination reactions of quinoline triflate and the effect of a Pd catalyst, its ligands, solvents, bases,
and temperature were studied. This method facilitated an easier pathway for the preparation of aminoquinoline derivatives
as potential precursors of new serotoninerg agents.
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4.
Paraskevas D. Tzanavaras Demetrius G. Themelis Fotini S. Kika 《Central European Journal of Chemistry》2007,5(1):1-12
The present study reviews more than twenty years (1985-present) of published research on the development and application of
analytical procedures for the determination of chlorine dioxide, a widely used disinfectant and bleaching agent. The review
covers a variety of techniques including batch and automated spectrophotometry and fluorimetry, electroanalysis and chromatography.
The analytical figures of merit to the methods are presented, while critical discussion regarding their advantages and disadvantages
is addressed.
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5.
A palladium complex with an aminophosphine ligand has been prepared and investigated as a catalyst precursor in Suzuki coupling
reactions in toluene. Nanoparticles composed of elemental palladium have been isolated from the reaction media and analyzed
using transmission electroscopic microscope (TEM), which shows the essential catalysts palladium nanoparticles to have a size
of ca. 3.0 nm.
dedicate to the 60th birthday of Prof. Dr. Yuan Kou 相似文献
6.
The determination of paeoniforin, paeonol, and censenoside Rg1 in traditional Chinese medicinal preparations, Tze Po San Pien pills and Liuwen Dihuang pills has been investigated by micellar
electrokinetic capillary electrophoresis with borate buffer (20 mM), sodium dodecylsulfate (30 mM) and acetonitrile (20%)
as background electrolytes (pH 9.30), 20 kV applied voltage and 203 nm UV detection. The effects of SDS concentration, borate,
buffer pH, and organic modifier on electrophoretic behavior and separation are discussed. Regression equations revealed linear
relationships between the peak-area of each component and the content with the correlation coefficients from 0.9982 to 0.9999.
In addition, the levels of the active compounds in two kinds of traditional Chinese medicinal preparations were easily determined
with the recoveries from 93.1% to 108.2%.
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7.
A. A. Massaoud H. A. Hanafi T. Siyam Z. A. Saleh F. A. Ali 《Central European Journal of Chemistry》2008,6(1):39-45
Poly (acrylamide-acrylic acid-dimethylaminoethylmethacrylate), p(AM-AA-DMAEM) and Poly(acrylamide-acrylic acid)-ethylenediaminetetracetic
acid disodium, p(AM-AA)-EDTANa2 were prepared by gamma radiation-induced template polymerization technique and used for the separation of Ga (III) from Cu
(II), Ni (II), and Zn (II) in aqueous media. The effect of pH and contact time on the separation process was studied. The
optimum pH value for the separation process is 3–3.5. The result shows that Ga (III) is first extracted while Cu (II), Ni
(II) and Zn(II) are slightly extracted at this pH value. The recovery of metals using HCl, HNO3 and H2SO4 has been studied. The resins may be regenerated using 2M HCl solutions.
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8.
Martin Přádný Lenka Martinová Jiří Michálek Tat’ána Fenclová Eva Krumbholcová 《Central European Journal of Chemistry》2007,5(3):779-792
The goal was to electrospin 2-hydroxyethyl methacrylate — based biocompatible polymers and prepare submicron fibres (nanofibers)
for biomedicinal applications. Syntheses of poly(2-hydroxyethyl methacrylate) (HEMA) and its copolymer with 2-ethoxyethyl
methacrylate (EOEMA), and their characterization by viscometry and molecular weight are described. Their relation to electrospinning
is discussed. Electrospinning of HEMA homopolymer from water-ethanol is successful for molecular weights 6.31 × 105 and 1.80 × 106 g/mol. Electrospinning of HEMA/EOEMA copolymers is feasible from ethanol.
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9.
Ksenija R. Kumrić Tatjana M. Trtić-Petrović Ljubiša M. Ignjatović Jožef J. Čomor 《Central European Journal of Chemistry》2008,6(1):65-69
Lutetium has been determined by differential pulse anodic stripping voltammetry in an acidic solution containing Zn-EDTA.
Lutetium (III) ions liberated zinc (II), which was preconcentrated on a hanging mercury drop electrode and stripped anodically,
resulting in peak current linearly dependent on lutetium (III) concentration. Less than 0.4 ng mL−1 lutetium could be detected after a 2 min deposition.
相似文献
10.
Ruta Bariseviciute Justinas Ceponkus Valdas Sablinskas 《Central European Journal of Chemistry》2007,5(1):71-86
A new method is used for the separation of ethene secondary ozonide (SOZ) from the other products of ethene ozonization reaction.
The reaction was performed in the neat films of the reactants at 77 K. Ethene SOZ was separated from other products of the
reaction by vacuum distillation at 190–210 K and analyzed by means of the matrix isolation IR absorption spectroscopy. Spectroscopic
data from photolysis of the matrix isolated ozonide was used as an argument for assignment of the infrared spectral bands
either to ethene SOZ or to other products of the reaction. The spectra of ethene SOZ isolated in the Ar matrix were analyzed
by combining experimental results with the theoretical calculations performed at the MP2 6-311+G (3df, 3pd) level.
A new assignment of some experimental fundamental bands is proposed taking in to account the Fermi resonance between CH stretch
and the five membered ring vibrations. For the first time more than 30 weak infrared absorption bands were observed and assigned
to various combination vibrations and overtones. By using new spectral information concerning the overtones and the combination
bands it is concluded that the dissociation of unstable ethene SOZ involving breaking of any of the four CO bonds of the five
membered ring of ethene SOZ has low probability. Dissociation of the ring starts from breaking of the OO bond.
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11.
The geometry, frequency and intensity of the vibrational bands of 8-hydroxyquinoline and its 5,7-dichloro, 5,7-dibromo, 5,7-diiodo
and 5,7-dinitro derivatives were obtained by the density functional theory (DFT) calculations with Becke3-Lee-Parr (B3LYP)
functional and 6-31G* basis set. The effects of chloride, bromide, iodide and nitro substituent on the vibrational frequencies
of 8-hydroxyquinoline have been investigated. The assignments have been proposed with aid of the results of normal coordinate
analysis. The observed and calculated spectra are found to be in good agreement.
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12.
Irina Yurkova Mikhail Kisel Juergen Arnhold Oleg Shadyro 《Central European Journal of Chemistry》2007,5(4):970-980
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and thin-layer chromatography
(TLC) have been used to study dopamine and iron mediated free-radical transformation of lipids in their hydrophilic parts.
It has been shown that the action of the dopamine/Fe2+ system on galactocerebroside or cardiolipin, which are the components of mixed micelles, results in formation of ceramide
or phosphatidic acid and phosphatidylhydroxyacetone, respectively. These data, when combined with results obtained using the
ascorbate/Fe2+/H2O2 oxidizing system with the same substrates, demonstrate that the formation of these products proceeds via an OH-radical induced
fragmentation taking place in polar moiety of the starting lipids.
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13.
Yuhai Sun Yujun Feng Hongwei Dong Zhi Chen Likun Han 《Central European Journal of Chemistry》2007,5(2):620-634
A series of homologous gemini surfactants possessing identical hydrophobic chains but different ionic head groups (cationic,
anionic, zwitterionic) were synthesized, and their aqueous solution properties were examined. The results showed that the
surface activities of gemini surfactants are superior to those of corresponding conventional monomeric surfactants, and molecular
arrangements of gemini surfactants at the air-water interface are tighter than those of corresponding conventional surfactants.
It was also found that zwitterionic gemini surfactant possesses the highest surface activity among the three surfactants.
The behavior at the air-water interface is closely related to the molecular structural features of surfactants, which provide
an indication for synthesizing highly-efficient surfactants.
相似文献
14.
Adina Raducan Alexandra Olteanu Mihaela Puiu Dumitru Oancea 《Central European Journal of Chemistry》2008,6(1):89-92
The kinetics of the reaction between malachite green (MG) and sodium hydroxide (MG fading) was studied using a spectrophotometric
method in the presence of two cationic surfactants, cetyl-benzyl-dimethyl-ammonium chloride (CBDAC) and hexadecyl-trimethylammonium
bromide (HTAB) and one anionic surfactant, sodium dodecyl sulphate (SDS) at concentrations below and above critical micellar
concentrations. The cationic surfactants have a catalytic effect, while the anionic surfactant has an inhibitory effect on
the reaction. A kinetic model describing the influence of surfactant on reaction rate was developed. The results are discussed
on the basis of electrostatic and hydrophobic interactions between the kinetic micelles and malachite green.
相似文献
15.
Surface analysis of the size-fractioned urban aerosols by secondary ion mass spectrometry (ToF-SIMS)
The secondary ion mass spectrometry method (ToF-SIMS) has been applied to the analysis of some mineral and organic species
on the surface layers of airborne urban particulates. Particulate matter was collected on aluminum sheets of the 8-stage Anderson
type cascade impactor from three different sampling sites in the city of Lodz, Poland, which were different in terms of aerosol
source apportionment. The obtained results show that vehicle combustion products occur mainly in fine fraction with aerodynamic
diameters below 1μm. The main contribution to the mineral components comes from direct and traffic related soil resuspension.
相似文献
16.
Emil Ioan Muresan Spiridon Oprea Theodor Malutan Mihai Vata 《Central European Journal of Chemistry》2007,5(3):715-726
The esterification reaction of palmitic acid with epichlorohydrin catalyzed by an anionic macroporous resin was studied. Purolite
A-500 resin proved to be a very effective catalyst in the synthesis of 3-chloro-2-hydroxypropyl palmitate. The effects of
certain parameters such as speed of agitation, catalyst particle size, catalyst loading, temperature, initial molar ratio
between reactants on the rate of reaction were studied. It was found that the overall rate is intrinsically kinetically controlled.
The structure of synthesized ester was confirmed by FTIR and 1H NMR analyses.
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17.
A procedure for direct electrochemical deposition of polyaniline-polypyrrole blend coating on the surface of stainless steel
wire was suggested. Incorporation of polyaniline and polypyrrole into the blend coating was confirmed by infrared spectroscopy.
Key parameters (pyrrole, aniline, dopant and sulphuric acid concentrations and deposition potential) influencing the coating’s
mechanical stability and surface homogeneity were optimised and thermostability of the coating was investigated. A possibility
to apply the coating as a new fibre for solid phase microextraction was demonstrated. The coating showed better selectivity
toward aromatic, hydrophobic compounds.
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18.
Li-Wen Xu Ming-Song Yang Jian-Xiong Jiang Hua-Yu Qiu Guo-Qiao Lai 《Central European Journal of Chemistry》2007,5(4):1073-1083
Ionic liquid-functionalized mesoporous materials exhibited high catalytic activity in versatile organic reactions, such as
cycloaddition of carbon dioxide (CO2) with epoxide, aza-Michael addition of amines to α, β-unsaturated carbonyl compounds, and the Biginelli reaction of aldehyde, ethyl acetoacetate and urea. Recycling of the catalyst
in these reactions could be carried out and the catalyst used at least five times without significant loss in activity.
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19.
Danuta Barałkiewicz Anetta Kanecka-Hanc Hanka Gramowska 《Central European Journal of Chemistry》2007,5(4):1148-1157
Pb, Mg and Ca were simultaneously determined in plant roots by slurry introduction into inductively coupled plasma optical
emission spectrometry (SS-ICP-OES). Slurries were prepared in 0.5% or 5% (v/v) HNO3 with 0.5, or 5% (v/v) Triton X-100. Omission of the Triton X-100 improved results. Compared with wet ashing of the root sample
followed by ICP-OES, ICP-MS and FAAS, the method offers: comparable results, simplification of sample preparation, less sample
contamination, and reduction in the use of dangerous and corrosive reagents. The precisions varied: 1.7% for Mg, 2.8% for
Ca and 4.3% for Pb, and were not significantly different (95% confidence level) from those of conventional analysis.
相似文献
20.
Electrochemical determination of dopamine (DA) in the presence of ascorbic acid (AA) was achieved on boron-doped diamond (BDD)
film electrode by differential pulse voltammetry. The experimental results indicated that the oxidative peaks of DA and AA
could be separated completely on anodically-treated (BDD) electrode without further modification, although these two peaks
can not be separated on glassy carbon electrode. The peak separation of DA and AA was developed to be 0.44 V. High sensitivity
was obtained to determine DA selectively with the coexisting of a large excess of AA in acidic media by DPV. The detection
limit of DA was achieved to be 1.1 × 10-6 M in the presence of AA with the concentration of 200 times more than DA. This technique was also applied to the determination
of DA in real samples.
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