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1.
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
2.
Tsonko Kolev Bojidarka B. Koleva Michael Spiteller 《Central European Journal of Chemistry》2008,6(3):393-399
The applications of linear-polarized IR-spectroscopy to oriented colloid suspensions in a nematic host are demonstrated with
croconic and rhodizonic acids. The experimental IR vibrational assignments of the solid-state of both neutral compounds are
presented. Assignments are supported by theoretical quantum chemical calculations and vibrational analysis at the DFT level
of theoretical approximation with the 6-311++G** basis set.
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3.
The paper reports on the dependence of the absorbance and luminescent intensity from pH of novel poly(oxyethylene phosphate)
tris(β-diketonate) europium (III) complexes. The photophysical data obtained allow some preliminary assumptions about the
nature of this phenomenon. Increase in luminescent efficiency is a consequence of enhanced efficiency of energy transfer caused
by structural changes in complexes after water deprotonation. Remarkable change has been observed in photophysical properties
of the polymer complexes by studying the fluorescent emission and excitation spectra and absorption recorded at various pH
both in solution and in the solid state. Some of the complexes derivative of the dibenzoylmethane (DBM) show more than hundred
times increase in the luminescence after alkalization. The pH value, at which the maximum luminescent efficiency appears,
depends on the type of the fourth ligand. The difference between luminescent efficiency of the complexes in alkaline and neutral
environment depends on the β-diketonate ligands and on polymer type as well.
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4.
D. A. Svechkarev G. V. Karpushina L. L. Lukatskaya A. O. Doroshenko 《Central European Journal of Chemistry》2008,6(3):443-449
Three 2-(benzimidazol-2-yl)-3-hydroxychromone derivatives were synthesized. Their spectroscopic and fluorescent properties,
due to excited state intramolecular proton transfer (ESIPT) from OH to carbonyl, were studied. Theoretical possibility of
an alternative intramolecular H-bonding and experimental evidence for such behavior are discussed.
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5.
Adriana Czímerová Alexander Čeklovský Juraj Bujdák 《Central European Journal of Chemistry》2009,7(3):343-353
Layer charge is one of the key parameters used for the characterisation of expandable clay minerals, smectites. It determines
most significant properties of the material which are important from the industrial application point of view. This work is
related to a novel method introduced to characterize the layer charge of smectites, based on using cationic organic dyes as
molecular sensors. One xanthene and four phenothiazine cationic dyes were tested using reduced charge montmorillonites (RCMs)
and compared with methylene blue, which has been used most frequently. The characterization of the charge was based on the
formation of molecular assemblies (H- and J-aggregates) composed by dye cations, which were easily detectable using absorption spectroscopy in the UV/VIS spectrum. More
detailed characterization of the spectra required calculations of second-derivative curves. For all of the reaction systems
tested in this work, the molecular aggregation increased with the layer charge of RCMs. Slight to moderate differences in
the formation of dye assemblies related to the differences in the molecular structures of the individual dye cations. For
example, the molecular asymmetry of azure A brought about the formation of coexistent species of similar structures. The structure
of the heteroaromatic skeleton affected the extent of the aggregation and spectral changes with time. The presence of reactive,
non-substituted amino groups in thionine cations probably partially decomposed in the clay mineral colloids based on high-charge
RCMs. Any of the tested dyes could be used as molecular sensors for empirical characterization of the layer charge of clays
taking into account the differences mentioned above.
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6.
Silica gel was chemically modified with Congo red and characterized by Fourier transform infrared spectroscopy, elemental
and thermogravimetric analysis. The pH-sensitive immobilized Congo red retains the same properties as its solution counterpart
and could be applied as solid indicator. The functionalized silica gel was also employed to extract different cations from
water solutions. The concentration of cations extracted was determined by inductively coupled plasma optical emission spectrometry.
The solid support is able to selectively extract silver and copper from water solutions and retains its properties after treatment
with different organic and inorganic solvents.
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7.
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.
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8.
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.
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9.
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.
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10.
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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11.
Raluca Turdean Elena Bogdan Anamaria Terec Anca Petran Laurian Vlase Ioan Turcu Ion Grosu 《Central European Journal of Chemistry》2009,7(1):111-117
The synthesis of new 3,7-dibromophenothiazine derivatives bearing bromoalkyl, mercaptoalkyl and alkylthioacetate groups on
the N atom at position 10 is reported. The Suzuki coupling reaction of one of these derivatives via the bromine atoms at positions
3 and 7 with bromothiophene derivatives is also discussed.
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12.
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.
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13.
This paper describes the preparation and characterization of poly(ethyl cyanoacrylate) colloidal particles loaded with the
organic fluorophore Rhodamine 6G. We studied the physicochemical properties of the colloidal particles: morphology, size-distribution,
ζ-potential, fluorescent properties and photobleaching upon UV-light illumination. The properties of the obtained colloidal
particles, as well as the dye loading efficiency, were found to depend on the concentrations of ethyl cyanoacrylate monomer
and Rhodamine 6G in the polymerization medium. The fluorophore release from the colloidal particles in aqueous buffer is also
studied.
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14.
15.
This article describes the simple hydrodehalogenation of halogenated anilines and their derivatives by the action of Raney
aluminium-nickel alloy in aqueous alkaline solution at room temperature. The reaction course was monitored by means of 1H
nuclear magnetic resonance (NMR) spectroscopy and GC-MS spectra.
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16.
The kinetics of the C-S coupling of arylmagnesium bromides with phenyl tosylate has been studied in THF: toluene at 90°C.
The reaction is first order in Grignard reagent and first order in phenyl tosylate. Kinetic data, Hammett relationship and
activation parameters are consistent with a nucleophilic addition mechanism involving rate determining attack of carbanion
to sulfonyl group followed by a fast phenoxide group leaving.
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17.
Olaf Kühl 《Central European Journal of Chemistry》2008,6(3):365-372
N-Heterocyclic germylenes are known to exist in two structurally different forms, the planar Meller germylenes and the monoimino
germylenes that feature an envelope structure. This essay reviews recent reports dealing with radical and cationic Meller
type germylenes featuring the monoimino germylene structure, discusses their transformations and relationships, and asks the
question whether indeed N-heterocyclic germylenes can be turned into Lewis acids.
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18.
Junhao Zhang Yuhui Wu Jia Zhu Shaoxing Huang Dongjing Zhang Qinghuan Yin 《Central European Journal of Chemistry》2010,8(5):1027-1033
Self-assembled CdS architectures with flower-like structures have been synthesized by a mixed solvothermal method using ethylene
glycol and oleic acid as the mixed solvent at 160°C for 12 h. The results of X-ray diffraction (XRD) patterns, field-emission
scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images indicate that the product exists as
the hexagonal wurtzite phase and conatins of larger numbers of flower-like CdS architectures with diameters of 1.8–3 μm. The
selected-area electron diffraction (SAED) pattern and the high resolution transmission electron microscope (HRTEM) image reveal
that the grain has better crystallinity. The optical properties of flower-like CdS architectures were also investigated by
ultraviolet-visable (UV-vis) and photoluminescence spectroscopy at room temperature. A strong peak at 490 nm is shown in the
UV-vis absorption, while an emission at 486 nm and another strong emission at 712 nm are shown in the PL spectrum.
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19.
Magda Milewska Katarzyna Guzow Wies?aw Wiczk 《Central European Journal of Chemistry》2010,8(3):674-686
The ability of new chelate ligands, benzoxazol-5-yl-alanine derivatives substituted in position 2 by heteroaromatic substituent,
to form complexes with selected metal ions in acetonitrile are studied by means of absorption and steady-state and time-resolved
fluorescence spectroscopy. Among the ligands studied, only azaaromatic derivatives form stable complexes with transition metal
ions in the ground state. Their absorption bands are bathochromically shifted enabling to use those ligands as ratiometric
sensors. The fluorescence of each ligand is quenched by metal ions, however, in the presence of Cd(II) and Zn(II) ions a new
red shifted emission band is observed.
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20.
Soufiane El Houssame Hafid Anane Larbi El Firdoussi Abdellah Karim 《Central European Journal of Chemistry》2008,6(3):470-476
The palladium(0) catalyzed amination of allylic acetates and carbonates derivatives from terpenic olefins was carried out
under mild conditions. The reaction offers a very good method for the preparation of allylic amines and thus to provide a
useful entry to new functionalized terpenic olefin products. The mechanism involving a formation of p-allyl-palladium intermediate
complex is in good agreement with the results obtained with the optically active substrates, as well as via an analysis of
the observed regio-and stereoselectivity.
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