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1
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Preparation and characterization of catalyst mix Fe-Co/MgO for carbon nanotubes growth

100%
Steplewska A., Jedrzejewski R., Borowiak-Palen E.
Polish Journal of Chemical Technology
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2008
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vol. 10
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issue 3
1-3
EN
Fe-Co/MgO is one of the most common catalyst mix applied to carbon nanotubes (CNTs) growth in chemical vapor deposition process. Therefore, here we present detailed study on the preparation and characterization of Fe-Co/MgO. The precursors of Fe and Co are iron (II) acetate and cobalt acetates, correspondingly. The molar ratio of the catalyst mix is Fe:Co:MgO=1:1:100. Initially, thermogravimetric analysis (TGA) of the mixture was performed. TGA analysis of it indicated the stepwise mass losses which pointed out the crucial thermal conditions for the changes in the elemental composition, morphology, crystallographic structure and vibrational properties. In current state of the art the lowest growth temperature for singlewalled carbon nanotubes is 550°C in CVD technique and here the characterization of the catalyst mix strongly suggest that this temperature can be decreased what would enhance the compatibility of CNT growth with current complementary metal-oxide-silicon (CMOS) technology for CNTs-based nanoelectronics. The morphology, crystallographic structure, elemental composition of the samples and its spectroscopic properties were performed via high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD) and Infrared spectroscopy (IR), respectively.
2
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Novel Ni−Fe-oxide systems for catalytic oxidation of cyanide in an aqueous phase

100%
Stoyanova M., Christoskova S.
Open Chemistry
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2005
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vol. 3
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issue 2
295-310
EN
Catalytic activity of mixed Ni−Fe oxide systems with respect to air oxidation of aqueous cyanide solution at 308 K was investigated. The catalysts employed were prepared by an oxidation-precipitation method at room temperature and were characterized by powder X-ray diffraction (XRD), Mössbauer spectroscopy, and chemical analysis. The cyanide oxidation rate was found to be dependent on the catalyst's calcination temperature, pH of the medium, and catalyst loading. Results revealed that the catalyst calcined at 120°C is the most active where up to 90% of free cyanide (4 mM) was removed after oxidation for 30 minutes in the presence of 2.5 g/L catalyst at pH 9.5. The cyanide conversion becomes less favorable as the pH of the solution increases (with other constant parameters). The selectivity data showed that carbon dioxide is the main oxidation product, regardless of pH of the solution.
3
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Microwave Assisted Fast Synthesis of CuO Nanoflakes: Catalytic Application in the Synthesis of 1,4-Dihydropyridine

100%
Bajaj S., Tekade P., Lakhotiya G., Borkar P.
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EN
CuO nanoflakes were successfully synthesized by microwave irradiation, using copper(II) sulphate and sodium hydroxide (NaOH) as the starting materials and ethanol as the solvent. The CuO nanoflakes were characterized by using techniques such as X-ray powder diffraction, field emission scanning electron microscopy, and UV-visible absorption spectroscopy, Fourier transform infra-red spectroscopy. The synthesized CuO nanoflakes were found to have morphology like nanoflakes with narrow size distribution and high purity. Moreover, the synthesized CuO nanoflakes were used as an efficient catalyst for synthesis of a series of dihydropyridine derivatives. Optimization studies with different catalysts and solvents reveal that CuO nanoparticle in the water/ethanol mixture is efficient catalyst/solvent system for the synthesis of dihydropyridine derivative.
4
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Technological aspects of the synthesis of 2,4-dichlorophenol

88%
Białek A., Moszczyński W.
Polish Journal of Chemical Technology
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2009
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vol. 11
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issue 2
21-30
EN
The main factors influencing the selectivity of chlorophenols synthesis were described. The loss of raw materials and the composition of wastes obtained in a conventional technology of 2,4-D production based on 2,4-dichlorophenol (2,4-DCP) of the 89% purity were presented. The influence of some homogenous catalysts on the selectivity of 2,4-dichlorophenol obtained in phenol and chlorine reaction was examined. Using the combined catalyst enables to chlorinate selectively the monochlorophenols to 2,4-DCP without an undesirable increasing of the 2,6-dichlorophenol and 2,4,6-trichlorophenol contents. The catalyst transformations during the reaction of phenol chlorination were investigated and the method of its elimination after the reaction was elaborated.
5
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Optimization of an active phase composition in the low-temperature nitric oxide reduction catalyst

88%
Kułażyński M., Bratek K., Walendziewski J.
Polish Journal of Chemical Technology
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2007
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vol. 9
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issue 3
33-37
EN
In the first research studies series a selection of the quantitative composition of catalyst active phase composition (iron, copper and manganese) deposited on mineral-carbon support was carried out. It was found on the basis of the selection studies series that the best results were attained when copper and manganese were used as catalyst components. The quantitative composition of the denitrogention catalyst was estimated using a statistical method of experiment planning and metals content changed in the range 0.5 - 1.5wt % for both metals. Catalyst activity in nitric oxide reduction by ammonia was determined in the dependence on an active phase composition in the temperature range 100 - 200°C, at GHSV (Gas Hour Space Velocity) 6 000 and 10 000 Nm3/m3h, NO concentration 400 ppm, NH3/NO ratio 1:1. A graphic presentation of the obtained results was made using the UNIPLOT program. The highest activity in nitric oxide reduction by ammonia presented copper - manganese catalysts prepared by the impregnation of mineral-carbon support with active metals salts solutions and calcination after each metal impregnation with copper (up to 1.5 wt %) and manganese (up to 1.5 wt %).
6
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Catalytic air oxidation of manganese in synthetic waters

88%
Kaya N., Karadurmus E., Alicilar A.
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EN
An attempt was made to study the oxidation of manganese by air in synthetic waters. A series of batch experments were performed at differnet values of concentration, temperature and pH. Unoxidized manganese in the solution was determined by formaldoxime spectrometric method. Results of these studies indicated that the air oxidation of manganese soluble in water can be effectively performed in basic media and that oxidation yield increasedwith an increase in pH and concentration. The yield was very high in the presence of manganese dioxide, sepiolite or clinoptilolite in solution and, the oxidation was almost completed especially at high values of pH and concentration. The reaction was found to be first order with respect to Mn2+ with a very low activation energy. A yield of 62% was obtained for the air oxidation of wastewater taken from the treatment plant of Corum Municipality.
7
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Effect of TiO2-ZnO/GAC on by-product distribution of CVOCs decomposition in a NTP-assisted catalysis system

88%
Abedi K., Ghorbani-Shahna F., Bahrami A., Jaleh B., Yarahmadi R.
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EN
In this study, the catalytic effect of TiO2-ZnO/GAC coupled with non-thermal plasma was investigated on the byproducts distribution of decomposition of chlorinated VOCs in gas streams. The effect of specific input energy, and initial gas composition was examined in a corona discharge reactor energized by a high frequency pulsed power supply. Detected by-products for catalytic NTP at 750 J L-1 included CO, CO2, Cl2, trichloroacetaldehyde, as well as trichlorobenzaldehyde with chloroform feeding, while they were dominated by CO, CO2, and lower abundance of trichlorobenzaldehyde and Cl2 with chlorobenzene introduction. Some of the by-products such as O3, NO, NO2, and COCl2 disappeared totally over TiO2-ZnO/GAC. Furthermore, the amount of heavy products such as trichlorobenzaldehyde decreased significantly in favor of small molecules such as CO, CO2, and Cl2 with the hybrid process. The selectivity towards COx soared up to 77% over the catalyst at 750 J L-1 and 100 ppm of chlorobenzene.
8
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One-pot synthesis of (S)-2-(6-methoxynaphtalen-2-yl)propanoic acid, (S)-Naproxen using Preyssler and Keggin-type heteropolyacids as green and reusable catalysts

88%
Gharib A., Daneshtalab M., Scheeren J., Bamoharram F., Roshani M., Jahangir M.
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EN
A simple, clean and environmentally benign route to the enantioselective synthesis of (S)-2-(6-methoxynaphtalen-2-yl)propanoic acid, (S)-Naproxen 3 is described by using Preyssler heteropolyacid, H14[NaP5W30O110], as a green and reusable catalyst in water and in the presence of 1-(6-methoxynaphthalen-2-yl)propan-1-one 1, D-mannitol 2. The products were obtained in very good yields.
9
Content available remote

Novel catalytic synthesis of 6,7-dimethoxyisatin with the use of heteropolyacids (HPAs) as acid solid catalyst

88%
Gharib A., Daneshtalab M., Scheeren J., Bamoharram F., Roshani M., Jahangir M.
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EN
An efficient method for the preparation of 6,7-dimethoxyisatin and its derivatives was developed with good yield by using Preyssler-type heteropolyacid (HPA) as acid catalyst under green conditions. The comparison between Keggin type heteropolyacids, H3[PW12O40], H4[SiW12O40] and H4[SiMo12O40], H3[PMo12O40] and mineral acids with Preyssler's anion shows that the latter possess better catalytical activity than the other heteropolyacids and no degradation of the structure was observed.
10
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Content available

Effect of NF3 Gas on Stabilization of Alkaline Earth Metal-CU Mordenite Catalysts During N2O Decomposition Reaction

75%
Seo M., Lee S.-Y., Cho S.-S., Song H. W., Kim H.-K., Kim D. S., Lee S.
Archives of Metallurgy and Materials
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2019
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vol. 64
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issue 2
11
Content available remote

The influence of a hard coal type on the degree of sulphur dioxide removal

75%
Marcewicz-Kuba A., Olszewska D.
Polish Journal of Chemical Technology
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2007
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vol. 9
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issue 3
127-129
EN
In this paper the authors have studied the properties of zeolite and montmorillonite doped with the nickel and cobalt cations in the removal of SO2 from the combustion gases process based on the DESONOX method. Burning coal from the hard coal from the Silesian Coal Basin mine "Julian" and the Lubelskie Coal Basin mine "Bogdanka" with supports only - did not show any reduction of the SO2 emission in the combustion gases.
12
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Thick-film gas microsensors based on tin dioxide

63%
Licznerski B.
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issue 1
13
Content available remote

Co(Salen) Catalysed Oxidation of Synthetic Lignin-Like Polymer: Naoh Effects

63%
Zhou X.-F.
Polish Journal of Chemical Technology
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2014
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vol. 16
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issue 3
91-96
EN
Abstract An attempt has been made to selectively oxidise synthetic lignin-like polymer for fine chemicals. The G- and S-type polymers (G- and S- type lignin model polymers) were synthesized using simple aromatic compounds as starting materials and then oxidised to benzaldehydes by reacting them with Co(salen) catalytic system. The reaction was characterized by measuring the change of the polymer with FTIR, C-13 NMR and GC-MS spectroscopy. The results obtained by the FTIR and C-13 NMR showed that the effects of NaOH were important and higher yield of benzaldehydes characterized by GC-MS in the presence of NaOH in the course of catalytic oxidation of the polymer demonstrated these effects. From the results, the catalyst could suitably be used in green procedures for lignin transformation.
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