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Wyświetlanie 1-8 z 8
Tytuł:
Study of the anatase to rutile transformation kinetics of the modified TiO2
Autorzy:
Grzmil, B.
Gleń, M.
Kic, B.
Lubkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/779360.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
TiO2
anatase
rutile
modification
phase transformation kinetics
Opis:
TiO2 attracts much interest because of its many potential applications. The use of titanium dioxide strongly depends on its polymorphic form: brookite, anatase, or rutile. Only rutile and anatase play an important role in industry. Anatase as a metastable form undergoes a non-reversible transformation into rutile. Understanding the kinetics of phase transformation and the processes of crystal growth of a material is essential for controlling its structure and, thus, its specific properties. The main purpose of this paper is to explain the anatase to rutile recrystallization kinetics in the modified TiO2 calcined from industrial hydrated titanium dioxide. The apparent activation energy of anatase to rutile transformation and the average size of titanium dioxide crystallites were determined for the unmodified TiO2 and TiO2 modified with P, K, Al, B, Zn, Zr, Ce, Sn, or Sb introduced in the amount of 0.5 mol% and 1.0 mol% when recalculated for their oxides. The growth of TiO2 crystallites during calcination was strongly inhibited by P, Ce and Zr, and inhibited to a lesser degree by Al, Sn and Sb. B and Zn did not affect the investigated process and K accelerated crystallites growth. The values of apparent activation energy depending on a modifier formed a relationship: Al
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 2; 73-80
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The dependance of an activity of vanadium catalysts on a carrier regeneration method and an active phase composition
Autorzy:
Grzesiak, P.
Grobela, M.
Hłyń, T.
Łukaszyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/780011.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
carrier properties
composition of active phase
SO2 oxidation
vanadium catalysts
Opis:
The results of the research studies concerning the reaction rate of SO2 oxidation on the vanadium catalysts have been described. A carrier of the active phase - silica has been regenerated from spent vanadium mass by leaching with H2SO4 solution. The dependence of the oxidation reaction rate on the method of treating a catalyst carrier as well as the composition of an active phase of the new catalyst systems has been also presented.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 4; 107-110
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Barium oxide as a modifier to stabilize the γ-Al2O3 structure
Autorzy:
Pakdeh, S. G.
Rasoolzadeh, M.
Moghadam, A. S.
Powiązania:
https://bibliotekanauki.pl/articles/778807.pdf
Data publikacji:
2016
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
γ-Al2O3
thermal stability
phase transition
barium oxide
pentacoordinated Al3+ ions
Opis:
This research concentrated on the structural stability of γ-alumina (γ-Al2O3 ) was investigated by a combination of differential thermal analysis, X-ray diffractometry and surface-area measurements. The γ –to– θ and then α phase transitions were observed as an exothermic peak at 1000°C–1400°C in the DTA curves. The role of barium oxide as a modifier to stabilize γ-Al2O3  structure has been investigated. XRD measurements show that after calcination at 1000°C for 2 h, a significant fraction of the pure γ-Al2O3  (BaO-free) transformed to θ-Al2O3  while that the transition phase in alumina samples modified by BaO have been reduced significantly. Barium oxide, eliminate pentacoordinated aluminum ions through coordinative saturation and alter these ions into octahedral cations and effectively suppressed the γ –to– α phase transition in Al2O3 , which concluded as improving the thermal stability and porous properties of the experimental samples.
Źródło:
Polish Journal of Chemical Technology; 2016, 18, 4; 1-4
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Epoxidation of 1-buten-3-ol under atmospheric pressure over the Ti-Beta catalyst
Autorzy:
Wróblewska, A.
Wajzberg, J.
Powiązania:
https://bibliotekanauki.pl/articles/779898.pdf
Data publikacji:
2007
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
epoksydacja w fazie ciekłej
1,2-epoksy-3-butanol
katalizator Ti-Beta
liquid phase epoxidation
1,2-epoxy-3-butanol
Ti-Beta catalyst
Opis:
The results of 1-buten-3-ol (1B3O) epoxidation with 30% hydrogen peroxide over the Ti-Beta catalyst were presented. The studies were performed under the atmospheric pressure and at the presence of methanol as a solvent. There was examined the influence of the following parameters: the temperature (0 - 60°C), the molar ratio of 1B3O/H2O2 (1:1 - 5:1), methanol concentration (5 - 90 wt%), the Ti-Beta catalyst concentration (0.1 - 5.0 wt%) and the reaction time (0.5 - 5.0 h). The optimal parameters were determined by using the following functions: the selectivity of the transformation to 1,2-epoxy-3-butanol (1,2E3B) in relation to 1B3O consumed, the selectivity of the transformation to organic compounds in relation to hydrogen peroxide consumed, the conversions of 1B3O and hydrogen peroxide. The main product of epoxidation was 1,2-epoxy-3-butanol, epoxide having several applications.
Źródło:
Polish Journal of Chemical Technology; 2007, 9, 2; 110-113
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The pressure method of 1-butene-3-ol epoxidation over Ti-beta catalyst
Autorzy:
Wróblewska, A.
Wajzberg, J.
Milchert, E.
Grzmil, B.
Ziebro, J.
Powiązania:
https://bibliotekanauki.pl/articles/779807.pdf
Data publikacji:
2007
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
epoksydacja w fazie ciekłej
1,2-epoksy-3-butanol
katalizator Ti-Beta
liquid phase epoxidation
1,2-epoxy-3-butanol
Ti-Beta catalyst
Opis:
The investigations of 1-buten-3-ol (1B3O) epoxidation by 30% hydrogen peroxide over Ti-Beta catalyst were performed. The experiments were carried out under the autogenic pressure and at the presence of methanol as a solvent. The influence of the following technological parameters on the course of epoxidation: temperature (20 - 120°C), the molar ratio of 1B3O/H2O2 (0.5:1 - 5:1), methanol concentration (5 - 90 wt%.), Ti-Beta concentration (0.1 - 5.0 wt%) and the reaction time (0.5 - 5.0 h) was investigated. The main functions describing the process were: the selectivity of transformation to 1,2-epoxy-3-butanol in relation to 1B3O consumed, conversions of substrates as well as the selectivity of transformation to organic compounds in relation hydrogen peroxide consumed.
Źródło:
Polish Journal of Chemical Technology; 2007, 9, 2; 53-56
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficiency of selected phase transfer catalysts for the synthesis of 1,2-epoxy-5,9-cyclododecadiene in the presence of H2O2/H3PW12O40 as catalytic system
Autorzy:
Lewandowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/778579.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
epoxidation
(Z,E,E)-1,5,9-cyclododecatriene
1,2-epoxy-5,9-cyclododecadiene
H2O2/H3PW12O40 catalytic system
phase transfer catalysis
Opis:
The results of the studies on the influence of the phase transfer catalyst on the epoxidation of (Z,E,E)-1,5,9-cyclododecatriene (CDT) to 1,2-epoxy-5,9-cyclododecadiene (ECDD) in the H2O2/H3PW12O40 system by a method of phase transfer catalysis (PTC) were presented. The following quaternary ammonium salts were used as phase transfer catalysts: methyltributylammonium chloride, (cetyl)pyridinium bromide, methyltrioctylammonium chloride, (cetyl)pyridinium chloride, dimethyl[dioctadecyl(76%)+dihexadecyl(24%)] ammonium chloride, tetrabutylammonium hydrogensulfate, didodecyldimethylammonium bromide and methyltrioctylammonium bromide. Their catalytic activity was evaluated on the basis of the degree of CDT and hydrogen peroxide conversion and the selectivities of transformation to ECDD in relation to consumed CDT and hydrogen peroxide. The most effective PT catalysts were selected based on the obtained results. Among the onium salts under study, the epoxidation of CDT with hydrogen peroxide proceeds the most effectively in the presence of methyltrioctylammonium chloride (Aliquat® 336) and (cetyl)pyridinium chloride (CPC). The relatively good results of CDT epoxidation were also achieved in the presence of Arquad® 2HT and (cetyl)pyridinium bromide.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 3; 96-99
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The new method of 1,2-epoxy-3-butanol production over titanium silicalite catalysts
Autorzy:
Wajzberg, J.
Wróblewska, A.
Powiązania:
https://bibliotekanauki.pl/articles/779811.pdf
Data publikacji:
2007
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
1,2-epoksy-3-butanol
epoksydacja w fazie ciekłej
TS-1
Ti-Beta
Ti-MCM-41
1,2-epoxy-3-butanol
liquid phase epoxidation
Opis:
The results of 1-butene-3-ol (1B3O) epoxidation over the titanium silicalite catalysts: TS-1, Ti-Beta, Ti-MCM-41 has been presented. The optimal parameters obtained for the individual catalyst were compared. The main functions describing the process were: the selectivity of transformation to 1,2-epoxy-3-butanol (1,2E3B) in relation to 1B3O consumed, the conversions of 1B3O and hydrogen peroxide and the selectivity of the transformation to organic compounds in relation to the H2O2 consumed. The main product of the epoxidation process was 1,2-epoksy-3-butanol, the chemical compounds having a lot of applications.
Źródło:
Polish Journal of Chemical Technology; 2007, 9, 2; 49-52
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bis(3-methyl-1-propene) ether and 3-(3-methyl-1-propene)-3-methyl-1,2-epoxypropane ether synthesis during the epoxidation of 1-butene-3-ol with hydrogen peroxide over the TS-2 catalyst
Autorzy:
Wróblewska, A.
Wójtowicz, G.
Powiązania:
https://bibliotekanauki.pl/articles/779202.pdf
Data publikacji:
2010
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
bis(3-methyl-1-propen) eter
3-(3-metylo-1-propen) eter-3-metylo-1 ,2-epoksypropan
TS-2
nadtlenek wodoru
epoksydowanie w fazie ciekłej
bis(3-methyl-1-propene) ether
3-(3-methyl-1-propene)-3-methyl-1,2-epoxypropane ether
hydrogen peroxide
epoxidation in liquid phase
Opis:
The influence of technological parameters on the transformation of 1-butene-3-ol (1B3O) to bis(3-methyl- 1-propene) ether (2x1B3O ether) and 3-(3-methyl-1-propene)-3-methyl-1,2-epoxypropane ether (1B3Ox1,2EB3O ether) over the TS-2 catalyst was presented. The reaction was performed in a glass reactor at atmospheric pressure and in methanol medium (protic solvent). The optimum conditions of 2x1B3O ether and 1B3Ox1,2EB3O ether obtaining were established by the mathematical method of experiments design (rotatable-uniform design) and after the analyses of the layer drawings.
Źródło:
Polish Journal of Chemical Technology; 2010, 12, 3; 66-71
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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