共查询到20条相似文献,搜索用时 31 毫秒
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Adsorption of Triton X-100 (TX-100) on silica gel has been studied as a function of temperature (308–328 K) and composition
for mixtures of water with ethanol or t-butanol. The adsorption capacity of silica gel for TX-100 decreases with increase
in alcohol content. Adsorption isotherms of TX-100 on silica gel are four-region and were analyzed using the ARIAN (adsorption
isotherm regional analysis) model. Data in regions 2, 3 and 4 were fitted to the Temkin, bilayer and reverse desorption isotherms,
respectively. The results show that adsorption of TX-100 on silica gel in water and alcohol-water binary mixtures occurs mainly
through formation of monolayer surface aggregates or low bilayer coverage.
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3.
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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4.
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.
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5.
Nitin A. Mirgane Sandip B. Kotwal Anil V. Karnik 《Central European Journal of Chemistry》2010,8(2):356-360
Ionic liquids (IL) are gaining importance as green solvents. Imidazolium ionic liquid [bmim]+[Cl]−, an environmentally benign solvent, was found to promote the Diels-Alder reaction between anthrone and maleimides at room
temperature with excellent yields. The ionic liquid played a dual role as solvent and catalyst.
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6.
New chiral enantiopure ureas and thioureas with (R,R)-TADDOL backbone were synthesized. Bis-(thio)ureas with C2 symmetry were obtained from TADDOL iso(thio)cyanates and bifunctional
amino-(thio)ureas from TADDAMINE, respectively. These were tested for carboxylate recognition capacity and the association
constant was determined for the most stable complex.
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7.
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.
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8.
Capillary electrophoresis (CE) is an attractive technique in separation science because of its high separation performance,
short analysis time and low cost. Electrochemical detection (EC) is a powerful tool for CE because of its high sensitivity.
In this review, developments of CE-EC from 2008 to August, 2011 are reviewed. We choose papers of innovative and novel results
to demonstrate the newest and most important progress in CE-EC.
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9.
Sushilkumar A. Jadhav 《Central European Journal of Chemistry》2012,10(5):1640-1646
Two new long-chain carboxylic acids (1, 2) bearing strong fluorescent group pyrene as ligands for Self-Assembled Monolayers (SAMs) have been synthesized. The multistep targeted synthesis is accomplished by use of Pyren-1-yl methylamine hydrochloride and employing simplified synthetic protocols. Compound 2 contains a chiral center purposely introduced along the atom chain in order to make it suitable for chiro-optical studies of the resulting SAMs. 相似文献
10.
The oxidation processes of 2,6-diisopropylnaphthalene and 4,4′-diisopropylbiphenyl with oxygen in the presence of a catalyst,
composed of copper(II) chloride and tetrabutylammonium bromide, were investigated. It was found that, in essence, only one
isopropyl group undergoes oxidation, and obtained mixtures contained mainly peroxide, alcohol, ketone and only small amounts
of hydroperoxide.
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11.
This paper presents an experimental characterization of two sources of calcium carbonate, limestone and calcium carbonate precipitate (CCP) used in wet flue gas desulphurization processes. Characterization of the two carbonate sources was carried out by chemical analysis, IR spectra, thermal behavior, particle size distribution for CCP, BET surface area and absorption capacity of SO2 in calcium carbonate suspensions. The absorption temperature, suspension concentration and carbonate grain size were found to be the most influential parameters in the absorption capacity measurements. 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.
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13.
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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15.
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.
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16.
Zhen-Yu Jiang Ji-Rong Wu Li Li Xi-Huai Chen Guo-Qiao Lai Jian-Xiong Jiang Yixin Lu Li-Wen Xu 《Central European Journal of Chemistry》2010,8(3):669-673
Lewis acid-assisted Br?nsted acid (LBA) catalysis was proposed for the iron-catalyzed Friedel-Crafts alkylation of indoles
with chalcones. This proposal was supported by the ESI-MS and cyclic voltammetry. The addition of acac to the iron-catalyzed
Friedel-Crafts alkylation of indoles with chalcones created a powerful catalytic system, which makes the alkylation reactions
occur easily under mild conditions.
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17.
Mariusz Walkowiak Daniel Waszak Błażej Gierczyk Grzegorz Schroeder 《Central European Journal of Chemistry》2008,6(4):600-606
Impact of silicon tripodand-type electrolyte additives and graphite pre-treatment agents on the electrochemical intercalation
of lithium cations into graphite was investigated. Addition of Si-tripodand-type silanes to propylene carbonate-based electrolytes
was found to suppress detrimental solvent co-intercalation and graphite exfoliation. Similar effects were observed for graphite
pre-treated with the reported silane agents. It was observed that the presented supramolecular additives allow for the formation
of effective passive layers on graphite during first charging, and thus can be considered as novel low-cost film-forming components
for rechargeable lithium batteries.
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18.
Ivan Talian Veronika Kováčová Marián Petrovič Ján Sabo 《Central European Journal of Chemistry》2012,10(4):1073-1078
Polyacrylamide gel electrophoresis is a powerful tool for protein mixture separation frequently used in proteomic studies.
This article describes the problems which can arise during the identification process of separated proteins by matrix assisted
laser desorption/ionization mass spectrometry. Presence of residual acrylamide monomers in the peptide samples leads to a
significant peptide signal suppression. In the case of protein prohibitin, isolated from the MCF 7 breast cancer cell line,
the peptide signal suppression was observed in 50% of all detected peptides.
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19.
Yevgen Karpichev Hubert Matondo Illia Kapitanov Oleksandr Savsunenko Marc Vedrenne Verena Poinsot Isabelle Rico-Lattes Armand Lattes 《Central European Journal of Chemistry》2012,10(4):1059-1065
A simple and efficient protocol for the preparation of a series of N-alkyl-3-boronopyridinium salts is described which requires exposure of 3-pyridineboronic acid neopentylglycol ester and corresponding alkyle halide to microwave irradiation followed by boronic ester hydrolysis. The technique employed drastically reduces the reaction time and prevents thermal degradation and the formation of side products. Water solutions of the obtained boronopyridinium salts are shown to be stable at room temperature in wide pH range as well as in the presence of hydrogen peroxide at pH 10.0 for 72 h. 相似文献
20.
Enthalpy increment measurements on melts in the system KF-K2TaF7 were carried out by drop calorimetry at temperatures between 298 K and 1063, 1103 and 1143 K for selected compositions. Heat
capacities of the melted mixtures and enthalpies of mixing have been determined. Careful calorimetric experiments showed small
but distinct non-ideality of the melt. The molar heat capacity of melt exhibits small positive divergence from additivity.
The molar enthalpy of mixing shows negative deviation from ideality which decreases with increasing temperature. The thermal
effect at mixing was assigned predominantly to association reactions producing more complex fluorotantalate anions. The formation
of complex anions with lower coordination number of Ta may not be excluded.
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