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Wyświetlanie 1-4 z 4
Tytuł:
Methanol as a High Purity Hydrogen Source for Fuel Cells: A Brief Review of Catalysts and Rate Expressions
Autorzy:
Madej-Lachowska, M.
Kulawska, M.
Słoczyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/185394.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
copper catalysts
noble metal catalysts
fuel cell
hydrogen production
CO-PROX
katalizatory miedziowe
katalizatory z metalu szlachetnego
ogniwo paliwowe
produkcja wodoru
Opis:
Hydrogen is the fuel of the future, therefore many hydrogen production methods are developed. At present, fuel cells are of great interest due to their energy efficiency and environmental benefits. A brief review of effective formation methods of hydrogen was conducted. It seems that hydrogen from steam reforming of methanol process is the best fuel source to be applied in fuel cells. In this process Cu-based complex catalysts proved to be the best. In presented work kinetic equations from available literature and catalysts are reported. However, hydrogen produced even in the presence of the most selective catalysts in this process is not pure enough for fuel cells and should be purified from CO. Currently, catalysts for hydrogen production are not sufficiently active in oxidation of carbon monoxide. A simple and effective method to lower CO level and obtain clean H2 is the preferential oxidation of monoxide carbon (CO-PROX). Over new CO-PROX catalysts the level of carbon monoxide can be lowered to a sufficient level of 10 ppm.
Źródło:
Chemical and Process Engineering; 2017, 38, 1; 147-162
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetic investigations on esterification of maleic anhydride with butanols
Autorzy:
Bartoszewicz, Maria
Kulawska, Maria
Organek, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/2034054.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acidic catalysts
butyl alcohol
dibutyl maleate
esterification reaction
plasticizer
katalizator kwasowy
alkohol butylowy
reakcja estryfikacji
plastyfikator
Opis:
Kinetic studies of esterification reaction of maleic anhydride with butan-1-ol, 2-methylpropan-1-ol and butan-2-ol were carried out in a semibatch reactor, in the presence of four acidic catalysts: sulfuric acid, phosphotungstic acid, ion exchange resin Dowex 50WX8 and tetrabutyl zirconate. Phosphotungstic acid proved to be the most active catalyst. The temperature range was 383–413 K, the initial molar ratio of alcohol to acid ranged 2.2-5:1. The kinetic parameters were given. The kinetics appeared to be that of the second order with respect both to the acid and to the alcohol. The reaction carried out in the presence of tetrabutyl zirconate was very slow and depended only on acid concentration. The effect of temperature on the reaction rate follows the Arrhenius equation well.
Źródło:
Chemical and Process Engineering; 2020, 41, 4; 293-306
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Copper/zinc catalysts in hydrogenation of carbon oxides
Autorzy:
Kulawska, M.
Madej-Lachowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/184893.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cu-based catalysts
methanol synthesis
steam reforming of methanol
higher aliphatic
alcohol synthesis
dimethyl ether
katalizator Cu
synteza metanolu
synteza alkoholu
eter dimetylowy
Opis:
A review concerning main processes of hydrogenation of carbon oxides towards synthesis of methanol, mixture of methanol and higher aliphatic alcohols and one-step synthesis of dimethyl ether as well as methanol steam reforming is given. Low-temperature methanol catalysts and low-temperature modified methanol catalysts containing copper as primary component and zinc as secondary one are described.
Źródło:
Chemical and Process Engineering; 2013, 34, 4; 479-496
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of ruthenium-based catalysts used in homogeneous transfer hydrogenation of acetophenone
Autorzy:
Mikołajczyk, Filip
Kamiński, Kamil
Powiązania:
https://bibliotekanauki.pl/articles/185307.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ruthenium-based catalysts
transfer hydrogenation
ketones
catalysis
RuCl2(PPh3)3
katalizatory na bazie rutenu
przeniesienie uwodornienia
ketony
kataliza
RuCl2 (PPh3) 3
Opis:
A detailed comparison of catalytic properties of two different ruthenium-based catalysts in the reaction of homogeneous hydrogenation of acetophenone was performed. Additionally, methods of synthesis of both catalysts were tested and optimized in order to achieve the best possible quality and purity of the final catalysts. NMR analysis was used to analyze and identify the composition of ruthenium compounds and gas chromatography was used to analyze the conversion rate of hydrogenation reactions. It was determined that RuCl2(PPh3)3 obtained with a modified method described by Shaw’s group (Shawet al., 2007) had the best catalytic properties in the reaction performed under conditions described in Liang Wang’s publication (Wang et al., 2014). It was also determined that for concentration ratio of substrate to RuCl2(PPh3)3 amounting to 250:1 the conversion rate was much higher than that of the reaction performed with a double dose of the catalyst. Results of experiments also show that samples of the post-reaction solution should be analyzed right after the reaction, because even if they are stored in low temperature the amount of product can change up to 3–5% compared to the base sample and this change is not predictable. These findings have significant implications for further research of the reaction of homogeneous transfer hydrogenation of ketones. With the right catalysts and methods of their synthesis other parameters of this reaction can be optimized. The most important one is a change of solvent from isopropyl alcohol to a less toxic substance like water. This may increase the value of the reaction in green chemistry and chemical industry.
Źródło:
Chemical and Process Engineering; 2019, 40, 2; 213--222
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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