共查询到20条相似文献,搜索用时 15 毫秒
1.
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.
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2.
Octavian Staicu Domnina Razus Valentin Munteanu Dumitru Oancea 《Central European Journal of Chemistry》2009,7(3):478-485
The heterogeneous catalytic ignition of lean to stoichiometric n-butane/air mixtures were studied at various total pressures
between 10 and 100 kPa and at temperatures equal to or larger than the critical ignition temperatures. The induction periods,
ignition and extinction temperatures were measured under strict isothermal conditions. The discussion presented in this paper
is based on several literature models. The data analysis allowed for the determination of the overall kinetic parameters.
The rigorous isothermal conditions indicated that the extinction temperatures are lower than the ignition, a behavior different
from the results obtained in stagnation-point flow reactors.
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3.
Vivek Srivastava 《Central European Journal of Chemistry》2010,8(2):269-272
Sulphonimide based organocatalyst was used to catalyze the aldol reaction in ionic liquid media. On the basis of yield and
selectivity the ionic liquid mediated system was found superior in comparison with organic solvents. The added advantages
of this ionic liquid mediated organocatalysis are easy recovery of product and the recyclability of the organocatalyst.
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4.
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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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.
A novel hydroxyamino phosphane was synthesised through the reaction of 2-imidazolidinone with ClPPh2 and subsequently reaction
of the resulting bisphosphino derivative with the Grignard reagent BrMgC5H11. The interaction of the pentyl substituent with one of the two phosphino groups and the structure in solution is shown by
multinuclear NMR-spectroscopy..
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7.
8.
Tuula Kylmälä Jan Tois Youjun Xu Robert Franzén 《Central European Journal of Chemistry》2009,7(4):818-826
Diflunisal and Felbinac, two FDA-approved NSAIDs and other biphenyl carboxylic acids were prepared in one step by a simple
and clean Suzuki cross-coupling reaction using an easily synthesized, air and moisture stable, palladium-diamine complex.
The yield (93%) for the one-step preparation of Diflunisal is the best reported without using a glovebox and a phoshine-based
catalyst.
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9.
Bingcheng Yang Feifang Zhang Xinmiao Liang 《Central European Journal of Chemistry》2012,10(3):472-479
This review summarizes the development of capillary ion chromatography (CIC) over approximately the last 5 years. It mainly
focuses on the technologic aspects of several key components associated with CIC, including micropump, microscale electrodialytic
eluent generator, microscale suppressor and the detector.
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10.
Santosh S. Katkar Pravinkumar H. Mohite Lakshman S. Gadekar Balasaheb R. Arbad Machhindra K. Lande 《Central European Journal of Chemistry》2010,8(2):320-325
A rapid and an efficient one-pot method for the synthesis of quinoxalines catalysed by ZnO-beta zeolite at room temperature
is described. This environmentally benign method provides several advantages over methods that are currently employed such
as a simple work-up, mild reaction conditions, good to excellent yields, and a process to recover and reuse the catalyst for
several cycles with consistent activity.
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11.
Ardeshir Shokrollahi Mojtaba Shamsipur Fahimeh Jalali Hamid Nomani 《Central European Journal of Chemistry》2009,7(4):938-944
A simple, sensitive and selective flotation method is described for the preconcentration and atomic absorption spectrometric
determination of zinc ion in water and blood samples. At a solution pH of 5.2, 4-(2-pyridylazo-resorcinol) and Triton X-114
were used as hydrophobic ligand and non-ionic surfactant, respectively. The chemical variables affecting the preconcentration
process were optimized. Under the optimized experimental conditions, the selective preconcentration and determination of as
low zinc concentration as 6.5 μg L−1 can be made. The proposed method was successfully applied to the preconcentration and low-level determination of zinc in
different water and blood serum samples.
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12.
The triplet excited state properties and photosensitization mechanisms of indigo were investigated based on density functional
theory calculations. The solvent effects on the photosensitization mechanisms of indigo have also been considered. The thermodynamic
feasibility of the possible 1O2 and O2·−-photogeneration pathways by triplet excited state indigo in different solvents was explored, in order to gain some deeper
insights into the photosensitization characters of the dye.
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13.
Lakshman S. Gadekar Shivshankar R. Mane Santosh S. Katkar Balasaheb R. Arbad Machhindra K. Lande 《Central European Journal of Chemistry》2009,7(3):550-554
Natural scolecite has been found as an effective catalyst for the one-pot synthesis of 2,4,5-triarylimidazole derivatives
via a three component reaction using benzil or benzoin, aldehydes and ammonium acetate. This method provides several advantages
such as being environmentally benign, reusable, possessing high yields with increased variations of the substituents in the
product and preparative simplicity.
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14.
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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15.
Renata Farkas Mercedesz Törincsi Pal Kolonits Jenö Fekete Oscar Jimenez Alonso Lajos Novak 《Central European Journal of Chemistry》2010,8(2):300-307
During the diazo-coupling reaction, nucleophilic displacement of a nitro group was also observed. This was the main reaction
(1→7) when the starting amine bore either a chlorine or methoxy group at the para position (1b–c). The newly prepared compounds (7) might serve as convenient building blocks in synthesis of some heterocycles.
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16.
17.
Oksana Makota Yuriy Trach Roman Leboda Jadwiga Skubiszewska-Zięba 《Central European Journal of Chemistry》2009,7(4):731-738
The catalytic effect of VSi2 on initial stages of the liquid-phase oxidation of cyclooctene by molecular oxygen was studied. The vanadium disilicide influences
on the oxidation process in the presence of hydroperoxide. VSi2 takes part in a radical formation stage by catalysis of hydroperoxide decomposition reaction. The catalyst was investigated
before and after reaction using FTIR spectroscopy. From the data obtained, the kinetic model of the catalytic oxidation process
was proposed and the equation for the reaction rate was derived. The equation has described all observed dependences of reaction
rate on the concentration of reactants and content of catalyst.
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18.
Robert Musiol Josef Jampilek Barbara Podeszwa Jacek Finster Dominik Tabak Jiri Dohnal Jaroslaw Polanski 《Central European Journal of Chemistry》2009,7(3):586-597
In the present paper we describe results on the synthesis and lipophilicity determination of a series of biologically active
compounds based on their heterocyclic structure. For synthesis of styrylquinoline-based compounds we applied microwave irradiation
and solid phase techniques. The correlation between RP-HPLC retention parameter log k (the logarithm of retention factor k) and log P data calculated in various ways is discussed, as well as, the relationships between the lipophilicity and the chemical structure
of the studied compounds.
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19.
Eugenia D. Teodor Simona C. Liţescu Antonela Neacşu Georgiana Truică Camelia Albu 《Central European Journal of Chemistry》2009,7(3):560-568
The study aims to establish several definite criteria which will differentiate Romanian amber and Baltic amber to certify
the local or Baltic origin of the materials found in archaeological sites on the Romanian territory, by using light microscopy
and performing analytical methods, such as Fourier transform infrared spectroscopy-variable angle reflectance and liquid chromatography
with mass spectrometry detection. Experiments especially by Fourier transformed infrared spectroscopy, were applied to a wide
range of samples with controlled origin. The methods were optimised and resulted in premises to apply the techniques to analysis
of the archaeological material.
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20.
Dominique R. Duguay Matthew T. Zamora Johanna M. Blacquiere Francis E. Appoh Christopher M. Vogels Susan L. Wheaton Felix J. Baerlocher Andreas Decken Stephen A. Westcott 《Central European Journal of Chemistry》2008,6(4):562-568
The addition of formylphenylboronic acid derivatives to thiourea and ethyl acetoacetate proceeds in the presence of an additional
Lewis acid catalyst to give the corresponding 3,4-dihydropyrimidin-2(1H)-(thio)ones (Biginelli products) in moderate yield.
Compounds were tested for antifungal activity against pure cultures of Aspergillus niger, Aspergillus flavus, Candida albicans and Saccharomyces cerevisiae but, unfortunately, none showed any appreciable activity.
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