共查询到20条相似文献,搜索用时 78 毫秒
1.
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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2.
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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3.
4.
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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5.
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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6.
Rodica Buhaceanu Ioan Sarghie Adriana Barsanescu Viorica Dulman Ioan Bunia 《Central European Journal of Chemistry》2009,7(4):827-835
The sorption capacity of three weak base ion exchangers based on acrylic copolymers functionalized with ethylenediamine, triethylenetetramine
and N, N- dimethylamino propylamine for Ag(I) ions was evaluated. Adsorption experiments were carried out by batch method.
The effect of pH, crosslinking degree of copolymers, amount of sorbent, initial ion concentration, contact time and temperature
was studied. The parameters which characterize the retention process were estimated using Langmuir and Freundlich isotherm
models, the best fitting being for the first model. Kinetic data were fitted to pseudo-first order, pseudo-second order and
intraparticle diffusion models. Experimental data were in good agreement with the pseudo second order.
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7.
Rayna Bryaskova Nelly Georgieva Dimitar Peshev 《Central European Journal of Chemistry》2010,8(5):1053-1058
Polyvinyl alcohol (PVA) and tetraethoxysilane (TEOS) hybrid materials were prepared by sol-gel methods and tested as matrices
for immobilization of Trichosporon cutaneum R57, capable of removing cadmium and copper ions from aqueous solutions. A kinetic model was applied and the effects of matrix
TEOS content on the copper and cadmium uptake equilibria and rate constants were investigated.
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8.
Kateřina Vítková Markéta Pechová Jan Petr Joanna Znaleziona Václav Ranc Vítězslav Maier Juraj Ševčík 《Central European Journal of Chemistry》2010,8(2):273-277
A method for the fast determination of yohimbine, a potent adrenoreceptor antagonist used for the treatment of sexual dysfunctions,
is proposed in this article. MEKC under basic and acidic conditions (sodium borate, pH 9.5 and sodium phosphate, pH 2.5) with
SDS was developed. The effect of the experimental parameters, e.g. pH, SDS concentration and injection time, on yohimbine
migration was also studied. Both methods were validated in terms of linearity, limits of detection and quantification, accuracy,
and precision using caffeine as an internal standard. The application for the determination of yohimbine in hand-made medicaments
is also investigated in this study.
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9.
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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10.
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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11.
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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12.
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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13.
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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14.
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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15.
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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16.
Dispersive liquid-liquid microextraction and liquid chromatographic determination of pentachlorophenol in water 总被引:1,自引:0,他引:1
Khalil Farhadi Mir A. Farajzadeh Amir A. Matin Paria Hashemi 《Central European Journal of Chemistry》2009,7(3):369-374
A simple and sensitive dispersive liquid-liquid microextraction method for extraction and preconcentration of pentachlorophenol
(PCP) in water samples is presented. After adjusting the sample pH to 3, extraction was performed in the presence of 1% W/V
sodium chloride by injecting 1 mL acetone as disperser solvent containing 15 μL tetrachloroethylene as extraction solvent.
The proposed DLLME method was followed by HPLC-DAD for determination of PCP. It has good linearity (0.994) with wide linear
dynamic range (0.1–1000 μg L−1) and low detection limit (0.03 μg L−1), which makes it suitable for determination of PCP in water samples.
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17.
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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18.
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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19.
Jorge García-Barrasa José M. López-de-Luzuriaga Miguel Monge 《Central European Journal of Chemistry》2011,9(1):7-19
Chemical methods provide an easy way to synthesize silver nanoparticles (Ag NPs) in solution. These metal nanoparticles have
a great potential for biomedical applications as an antibacterial, antifungal, and antiviral agent or in wound healing. The
adjustment of the parameters involved in these reactions permits a precise control over the size, shape, monodispersity, and
the surfaces of the nanoparticles. These nanoparticles are being used in the design of new hybrid organic-inorganic or inorganic
nanomaterials for biomedical applications.
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20.
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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