共查询到20条相似文献,搜索用时 951 毫秒
1.
Mónica Díaz-Pérez Manuel Aboal-Somoza Pilar Bermejo-Barrera Adela Bermejo-Barrera 《Central European Journal of Chemistry》2008,6(4):520-525
Preliminary results of development of a direct and fast method of determination of antimony in samples of tap water using
GFAAS are presented. The found levels of antimony were lower than permitted for human consumption. A mixture of Pd and Mg(NO3)2 (concentrations in the injected solution: 8.6 μg mL−1 and 5.8 μg mL−1 respectively) was used as the chemical modifier. The pyrolysis and atomization temperatures were 1000 and 1700°C, respectively
and the mean analytical recovery 98.2%.
相似文献
2.
Oliver Staller Dietmar Holzmann Gerhard Gritzner Pavel Diko Daniel Mikolaj František Kováč 《Central European Journal of Chemistry》2008,6(2):135-139
Textured Ni tapes were fabricated from commercially available nickel pellets (98.5% Ni). Ingots produced by a melt process
were cold rolled to 150–400 μm thick tapes. Texturing was achieved by annealing in a reducing atmosphere (Ar + 6.5% v/v H2). Sharp cubic biaxial textured Ni tapes were obtained by thermal treatment at 1000°C for 2 hours in a reducing atmosphere.
The tapes were characterized by scanning electron microscopy, X-ray diffraction and by electron backscattering diffraction.
The tensile strength, the thermal expansion behavior and the Vickers hardness for the cold rolled tapes and for the heat-treated
tapes were measured.
相似文献
3.
Sandip A. Sadaphal Kiran F. Shelke Swapnil S. Sonar Murlidhar S. Shingare 《Central European Journal of Chemistry》2008,6(4):622-626
1-benzyl-3-methyl imidazolium hydrogen sulphate [bnmim][HSO4] was found to be an effective catalyst for the condensation reaction of indoles and derivatives with benzaldehydes in microwave
irradiation with lower reaction time and higher yields to give bis(indolyl) methanes.
相似文献
4.
İlkay Şişman Çağla Tütünoğlu Ali Osman Aydın 《Central European Journal of Chemistry》2008,6(2):253-257
Sub-micrometer nickel powders of controlled size and morphology were produced by a surfactant-assisted polyol method, using
ethylene glycol (EG) as solvent and reductant in the presence of sodium dodecyl sulfate (SDS) surfactant and NaOH. The resultant
Ni powders were characterized by XRD, SEM, EDS, and FTIR. Spherical, hexagonal, and triangular fcc Ni powders from 0.30 to
0.60 μm were obtained in the presence of SDS; irregular spherical fcc Ni powders were obtained in its absence. The concentrations
of SDS, NaOH and Ni(CH3COO)2·4H2O greatly influence the product morphology and size.
相似文献
5.
Carla Ferragina Romolo Di Rocco Pasquale Patrono Lucantonio Petrilli 《Central European Journal of Chemistry》2009,7(1):31-34
Layered compounds with CdS particles supported on the ion-exchanger, γ-titanium dihydrogen phosphate, were prepared by the
stepwise reaction of the ion-exchanger and cadmium solution, followed by reaction with H2S gas. The CdS content on the ion-exchanger is dependent on the timeframe of the H2S gas flow. The materials obtained were layered, as shown by the X-ray measurements that exhibit both precursor and CdS diffraction
peaks. The thermal treatment of the material obtained gives evidence of its stability (≤ 320°C) before the CdS decomposition,
which occurs in a single step.
相似文献
6.
A one-pot multi-component reaction is developed for the efficient synthesis of 4,5-dibenzylidene octahydroacridines in high
yields. The reaction is performed by the tandem reaction of three molar equivalent aromatic aldehydes with two molar equivalent
4-alkylcyclohexanone in the system of NH4OAc/HOAc under microwave irradiation.
相似文献
7.
Jorge Luis Sague Doimeadios 《Central European Journal of Chemistry》2008,6(4):505-508
Herein, the first example of a co-crystal system formed by an imidazolium nitrate, a carbene precursor, and copper (II) nitrate,
{[Cu(NO3)2(H2O)2]L1(NO3)2} (1) (L1 = 1,1′-dibenzyl-3,3′-butyl-diimidazolium-2,2′-diylidene) is reported. These two building blocks are connected in the solid
state through hydrogen bonds to generate a three-dimensional supramolecular network.
相似文献
8.
Tevhide Özkaya Abdulhadi Baykal Muhammet Sadaka Toprak 《Central European Journal of Chemistry》2008,6(3):465-469
Water-soluble Mn3O4 nanocrystals have been prepared through thermal decomposition in a high temperature boiling solvent, 2-pyrrolidone. The final
product was characterized with XRD, SEM, TEM, FTIR and Zeta Potential measurements. Average crystallite size was calculated
as ∼15 nm using XRD peak broadening. TEM analysis revealed spherical nanoparticles with an average diameter of 14±0.4 nm.
FTIR analysis indicated that 2-pyrrolidone coordinates with the Mn3O4 nanocrystals only via O from the carbonyl group, thus confining their growth and protecting their surfaces from interaction
with neighboring particles.
相似文献
9.
In this report, we described the synthesis and characterization of a variety of diaminotriarylmethane derivatives with dimethylamino
functional groups. These compounds were synthesized by the tandem regio-selective electrophilic aromatic substitution reaction
of N,N-dimethylaniline with aryl aldehydes to form the corresponding diaminotriarylmethane compounds. In our strategy, Bi(NO3)3 was used as a catalyst under solvent free conditions to afford the desired products in good to excellent yields.
相似文献
10.
Francis E. Appoh Marcy J. Manning Teri J. Gullon Margaret A. Hansen Emily C. Bevans Krista D. M. Hogan Courtney S. Turner Christopher M. Vogels Andreas Decken Stephen A. Westcott 《Central European Journal of Chemistry》2008,6(3):359-364
The Ugi reaction with formylphenylboronic acid derivatives as the carbonyl component proceeds to give the corresponding boron-containing
dipeptide derivatives (Ugi products) in good yields.
相似文献
11.
Ágnes Zsigmond Suhsen Undrala Ferenc Notheisz Áron Szöllősy József Bakos 《Central European Journal of Chemistry》2008,6(4):549-554
Using a modified Augustine’s method variously substituted Rh complexes were anchored on Al2O3 support. The prepared catalysts were characterized by spectroscopic methods and were applied in the hydrogenation of several
acetophenone derivatives (p-CF3-acetophenone, acetophenone, p-NH2-acetophenone). Enantioselective C=O hydrogenations were observed with reasonable activity and selectivity on all heterogenized
complexes, e.e. up to 80%. At the same time the immobilized samples showed the advantages of the heterogeneous systems: easy handling and
recyclability.
相似文献
12.
Nikolai N. Kolesnikov Elena B. Borisenko Dmitrii N. Borisenko Boris A. Gnesin 《Central European Journal of Chemistry》2011,9(4):619-623
In the present study newly produced semiconductor ceramic nanopowder materials made of CdTe and Cd1−xZnxTe (CZT) are considered. Common features and differences in microstructures, phase transformations, grain growth and properties
of the ceramic materials of the binary and ternary compositions are studied.
相似文献
13.
Noora Kuuloja Tuula Kylmälä Youjun Xu Robert Franzén 《Central European Journal of Chemistry》2008,6(3):390-392
Xenbucin 1, an analgesic drug, was synthesized in 4 steps using two different routes. The biaryl fragment could successfully be produced
via a Pd/C catalysed Suzuki coupling in water using sodium tetraphenylborate as a phenylation reagent. Overall yields of the
routes were 36% and 59%, respectively.
相似文献
14.
Yonglei Chen Wenjuan Lü Xingguo Chen Min Teng 《Central European Journal of Chemistry》2012,10(3):611-638
Capillary electrophoresis (CE) has become one of the most useful tools in separation science because of its high separation
efficiency, low cost, versatility, ease of sample preparation and automation. However, some limitations of CE, such as poor
concentration sensitivity due to its lower sample loading and shorter optical path length, limits its further applications
in separation science. In order to solve this problem, various on-line sample preconcentration techniques such as transient
isotachophoresis preconcentration, field-enhanced sample stacking, micelle to solvent stacking, micelle collapse, dynamic
pH junction, sweeping, solid phase extraction, single drop microextraction and liquid phase microextraction have been combined
with CE. Recent developments, applications and some variants together with different combinations of these techniques integrating
in CE are reviewed here and our discussions will be confined to the past three years (2008–2011).
相似文献
15.
Phase equilibria established in the PbO - BiVO4 system over the whole component concentration range up to 1000°C have been investigated. A phase diagram has been constructed
using DTA and XRD.
相似文献
16.
Mi?osz Mi?tkiewski Beata Powa?a Bartosz Staniszewski Maciej Kubicki W?odzimierz Urbaniak Cezary Pietraszuk 《Central European Journal of Chemistry》2011,9(4):728-736
Selected β-diketones bearing unsaturated derivatives have been demonstrated to undergo homo-metathesis and cross-metathesis with selected
olefins in the presence of Grubbs catalysts. The reactions led to respective homo- and cross-metathesis products mainly with
good yields and selectivities.
相似文献
17.
The interaction between bovine serum albumin and the mono azo reactive dye Orange ZT has been investigated using absorption
difference spectroscopy. The influence of pH and ionic strength of the solution on the stability of the dye-protein complex
has been determined. At 25°C, the complex dissociation constants were equal to 24.0, 28.0, 7.0, 11.0, 17.6 and 46.0 μM at
pH 7.0, 6.5, 6.0, 5.5, 5.0 and 4.3, respectively. In the presence of 0.1, 0.2, 0.3 M KCl, at pH 6.0 and 25°C, the complex
dissociation constants were 8.8, 20.0, 18.0 μM, respectively. The protein-dye complex dissociation constants show that Orange
ZT could be used as an affinity ligand for protein purification.
相似文献
18.
Seied M. Pourmortazavi Iraj Kohsari Seiedeh S. Hajimirsadeghi 《Central European Journal of Chemistry》2009,7(1):74-78
The present study concerns the electrochemical synthesis of basic copper carbonate nanoparticles by oxidation of metallic
copper on the anode in an aqueous bicarbonate solution. This simple and one-step preparation can be considered as green synthesis.
The scanning electron microscopy (SEM) analysis indicates that average particle size of the product is in the range of about
70 nm. On the other hand, basic copper carbonate micro-powder has been prepared, by mixing solutions of copper(II) sulphate
and sodiu bicarbonate. The SEM analysis showed that the size of particles prepared in the same way is in the range of about
1 μm. In another part of this study, the thermal decomposition of micro and nanoparticles of copper carbonate produced by
various methods was studied in air using TG-DTA techniques. The results of thermal study show that the decomposition of both
samples occurs in single step. Also, the TG-DTA analysis of the nanoparticles indicates that the main thermal degradation
occurs in the temperature range of 245–315°C. However, microparticles of Cu(OH)2 · CuCO3 decomposed endothermally in the temperature range of 230–330°C.
相似文献
19.
The relative enthalpies of melts in the system KF - K2NbF7 were measured by drop-calorimetry at the temperatures 1058, 1140 and 1208 K as a function of composition. Heat capacities
of melted mixtures and enthalpies of mixing were determined using the experimental data. The molar heat capacity of melts
diverges slightly from additivity. The molar enthalpy of mixing of melts shows small negative deviation from ideality which
decreases with decreasing temperature. The thermal effect at mixing was assigned predominantly to association reactions producing
more complex fluoroniobate anions.
相似文献
20.
Ghasem Rezanejade Bardajee Farnaz Jafarpour Hamid Samareh Afsari 《Central European Journal of Chemistry》2010,8(2):370-374
In this report, a rapid, efficient and environmental friendly synthesis of 3-carboxycoumarins under ultrasound irradiation
in water media is described. The Knoevenagel condensation of Meldrum’s acid with substituted benzaldehydes in the presence
of zirconium oxide chloride (ZrOCl2·8H2O) and ultrasonic irradiation in water gave the corresponding 3-carboxycoumarins in good to excellent yields.
相似文献