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Wyszukujesz frazę "heterogeneous" wg kryterium: Wszystkie pola


Wyświetlanie 1-10 z 10
Tytuł:
Influence of heterogeneous nucleation on thermodynamic properties of isotactic polypropylene
Autorzy:
Barczewski, M.
Dobrzyńska-Mizera, M.
Trzeciak, M.
Powiązania:
https://bibliotekanauki.pl/articles/778993.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
isotactic polypropylene
PP
heterogeneous
nucleation
modification
sorbitol
DMTA
DSC
Opis:
In this paper we have investigated the effect of 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol sorbitol used in varying amounts (0.01 - 1 wt %) on isotactic polypropylene (iPP) matrix. We have used dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) to study glass transition temperatures and crystallinity as a function of the nucleating agent concentration. Isotactic polypropylene samples showed a strong dependency on amount of α nucleating agent used. An increasing content of sorbitol based nucleating agent led to an increase of crystallization temperature upon cooling from the melt at constant rate and a decrease of the glass transition temperatures.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 4; 71-74
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SCMNPs@Uridine/Zn: An efficient and reusable heterogeneous nanocatalyst for the rapid one-pot synthesis of tricyclic fused pyrazolopyranopyrimidine and 3-methyl carboxylate substituted pyrano[2,3-c]pyrazole derivatives under solvent-free conditions
Autorzy:
Wei, Jia
Gui, Wenjun
Cui, Yanjun
Zhang, Zhifang
Yousif, Qahtan A.
Powiązania:
https://bibliotekanauki.pl/articles/778587.pdf
Data publikacji:
2020
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
nanocatalyst
synthesis of tricyclic
carboxylate
efficient heterogeneous
Opis:
SCMNPs@Uridine/Zn is utilized as an environmental-friendly and efficient heterogeneous nanocatalyst for two one-pot four-component condensation reactions, containing hydrazine hydrate, arylaldehyde, ethyl acetoacetate, and barbituric acid to yield tricyclic fused pyrazolopyranopyrimidine derivatives (5a-q), and hydrazine hydrate, arylaldehyde, malononitrile, and dimethyl acetylenedicarboxylate/diethyl acetylenedicarboxylate to yield 3-methyl carboxylate substituted pyrano[2,3-c]pyrazole derivatives (8a-y) under solvent-free conditions with high to excellent yields. The main advantages of this process are easy work-up, short reaction times, no chromatographic purifications, and recyclability of the catalyst for a minimum of six runs without any signifcant decrease in yields of the products. Also, the prepared catalyst SCMNPs@Uridine/Zn was synthesized and fully characterized by various techniques including Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Raman spectroscopy.
Źródło:
Polish Journal of Chemical Technology; 2020, 22, 2; 20-33
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scaling diminution by heterogeneous crystallization in a filtration element integrated with membrane distillation module
Autorzy:
Gryta, M.
Powiązania:
https://bibliotekanauki.pl/articles/779308.pdf
Data publikacji:
2009
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
destylacja membranowa
moduł kapilarny
odsalanie wody
membrane distillation
capillary module
scaling
water desalination
Opis:
Water desalination by membrane distillation is restricted by calcium carbonate precipitation on the membrane surface, what resulted in a progressive decline of the permeate flux. The module rinsing by HCl solution removed this deposit, however, such operation could cause the membrane wettability, associated with lowering of the permeate flux. This phenomenon was inhibited when the membrane modules with prefiltration element, assembled directly at the inlet to module, were used. The salt deposits were formed mainly on the surface of the filtration element (nets area constituted over 10% of the membranes area), what protected the membranes assembled inside the module. The filter efficiency decreased when the deposit layer covered the entire surface of pre-filter element, and after a few hours (period of 10-20 h) the formation of crystallite on the membrane surface was also observed. Therefore, the formed deposit was systematically removed (at every 5 h) from this pre-filter by 3 wt.% HCl solutions. The periodical rinsing of nets by acid did not have a negative influence on the membrane.
Źródło:
Polish Journal of Chemical Technology; 2009, 11, 2; 60-65
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Esterification of fatty acids with C8-C9 alcohols over selected sulfonic heterogeneous catalysts
Autorzy:
Nowicki, J.
Mosio-Mosiewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/779516.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
esterification of fatty acids
C8-C9 alcohols
sulfonic acid catalysts
Opis:
A study on the synthesis of esters of fatty acids of natural origin (oleic acid from rapeseed oil) and branched synthetic isostearic acid with commercially available alcohols C8-C9 i.e. 2-ethylhexanol (2-EH) and 3,5,5-trimethylhexanol (TMH) in the presence of selected heterogeneous catalysts containing active sulfonic groups has been made. The catalysts were obtained using ready available amorphous silicas with different textural characteristics. The influence of catalyst porosity on the catalytic properties in the esterification of fatty acids has been investigated. The effect of the synthesis temperature has also been studied. The results were compared with the results of esterification with the use of acidic ion exchange resins. It was shown that catalysts obtained on the basis of amorphous silicas are good and reusable catalysts for the esterification of fatty acids with higher alcohols.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 3; 42-47
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphene hydrogels with embedded metal nanoparticles as efficient catalysts in 4-nitrophenol reduction and methylene blue decolorization
Autorzy:
Żelechowska, K.
Kondratowicz, I.
Gazda, M.
Powiązania:
https://bibliotekanauki.pl/articles/779599.pdf
Data publikacji:
2016
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
graphene hydrogel
metallic nanoparticles
heterogeneous catalyst
4-nitrophenol reduction
Opis:
Synthesis and characterization of the graphene hydrogels with three different metallic nanoparticles, that is Au, Ag and Cu, respectively is presented. Synthesized in a one-pot approach graphene hydrogels with embedded metallic nanoparticles were tested as heterogeneous catalysts in a model reaction of 4-nitrophenol reduction. The highest activity was obtained for graphene hydrogel with Cu nanoparticles and additional reaction of methylene blued degradation was evaluated using this system. The obtained outstanding catalytic activity arises from the synergistic effect of graphene and metallic nanoparticles. The hydrogel form of the catalyst benefits in the easiness in separation from the reaction mixture (for example using tweezers) and reusability.
Źródło:
Polish Journal of Chemical Technology; 2016, 18, 4; 47-55
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heterogeneous photocatalytic removal and reaction kinetics of Rhodamine-B dye with Au loaded TiO2 nanohybrid catalysts
Autorzy:
Zhang, D.
Powiązania:
https://bibliotekanauki.pl/articles/779739.pdf
Data publikacji:
2012
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
rozpad kinetyczny
rodamina B
katalizator Au/TiO2
Au/TiO2 catalyst
rhodamine B
decompose kinetics
Opis:
Heterogeneous photocatalytic removal of Rhodamine-B (RhB) dye by metallic Au nanopatrticles deposited TiO2 photocatalyst was studied. For this study, a chemical reduction method by hydrazine hydrate for gold deposition was employed in order to synthesize Au/TiO2 nanocomposite system. For the characterization of the synthesized nanomaterials, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), the Fourier transformation infrared spectroscopy (FTIR) and photoluminescence spectroscopy (PLS) techniques were performed. The obtained results show that the deposition of gold onto TiO2 surface could effectively inhibit the recombination of the photoinduced electron and holes, improving the absorption capability for the visible light source and leading to the increased surface OH group density. The degradation experiment reveals that the efficiency of color removal from RhB aqueous solution containing Au/TiO2 powders for the photocatalytic bleaching of RhB dye is more efficient than that of bare TiO2 sample upon UV-vis light activation. In addition, degradation kinetics of RhB dye in aqueous suspensions can be well simulated by the Langmuir-Hinshelwood model and obeys the pseudo-first order law, with a decolorization rate of 0.0252 min-1 to the photocatalytic removal of RhB dye.
Źródło:
Polish Journal of Chemical Technology; 2012, 14, 2; 42-48
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Montmorillonite as the catalyst in oxidation of limonene with hydrogen peroxide and in isomerization of limonene
Autorzy:
Malko, M.
Antosik, A. K.
Wróblewska, A.
Czech, Z.
Wilpiszewska, K.
Miądlicki, P.
Michalkiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/779496.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
montmorillonite
R-(+)-limonene
oxidation
isomerization
hydrogen peroxide
heterogeneous catalysis
Opis:
In our studies montmorillonite (MMT) was used as the heterogeneous, natural catalyst. This material was previously prepared by bentonite purification with help of the sedimentation method. The obtained catalyst was characterized by: XRD, SEM, BET and EDX. Catalytic tests with montmorillonite as the catalyst were performed with the natural terpene – R-(+)-limonene. This compound was oxidized with hydrogen peroxide and, moreover, in the separate process it was also isomerized. As the main products of limonene oxidation were detected: (1,2-8,9)-diepoxide, perillyl alcohol, carvone, carveol, 1,2-epoxylimonene and 1,2-epoxylimonene diol. In the isomerization of R-(+)-limonene were formed: terpinenes, terpinolene and p-cymene. Conversions of limonene in these processes reached 70–80%. The application of montmorillonite (the natural of origin) in the studied processes (oxidation and isomerization) is environmentally friendly, it allows to reduce the cost of the studied processes. The resulting products of the processes of oxidation and isomerization of R-(+)-limonene have many applications.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 4; 50-58
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation study of an auto-thermal double-membrane reactor for the simultaneous production of hydrogen and methanol: comparison of two different hydrogen redistribution strategies along the reactor
Autorzy:
Rahmani, F.
Haghighi, M.
Estifaee, P.
Rahimpour, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/779084.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
pure hydrogen production
methanol synthesis
auto-thermal double-membrane reactor
steady-state heterogeneous model
operation mode
Opis:
In a continuing effort to realize the simultaneous hydrogen and methanol production via the auto-thermal methanol synthesis process, the effect of two different hydrogen redistribution strategies along a double-membrane reactor has been considered. A steady-state one-dimensional heterogeneous model was developed to compare two strategies applied in the operation of the auto-thermal methanol synthesis. It was found that the counter-current configuration exhibited the better performance compared to the reactor operated in the co-current mode from both the economic and environmental points of view. This superiority is ascribed to the establishment of a more favourable temperature profile along the reactor and also more hydrogen extraction from the reaction zone. Moreover, the influence of some operating variables was investigated on the performance of the auto-thermal double-membrane reactor in the counter-current configuration. The results suggest that utilizing this configuration for pure hydrogen and methanol production could be feasible and beneficial.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 2; 115-124
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biodiesel production from Argemone mexicana seed oil using crystalline manganese carbonate
Autorzy:
Rao, R. Y.
Zubaidha, P. K.
Kondhare, D. D.
Reddy, N.J.
Deshmukh, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/778331.pdf
Data publikacji:
2012
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
biodiesel
estry metylowe kwasów tłuszczowych
olej z nasion Argemona meksykańskiegp
krystaliczny węglan manganu
kataliza wielofazowa
fatty acid methyl esters
argemone mexicana seed oil
crystalline Manganese carbonate
heterogeneous catalyst
Opis:
This communication explores the feasibility of biodiesel production from a weed plant Argemone mexicana seed oil and an efficient catalyst crystalline manganese carbonate. To the best of the authors' knowledge, this is the first study making use of pure, crystalline, ash colored manganese carbonate as a heterogeneous catalyst for the production of methyl esters as fuel from Argemone mexicana seed oil. The optimum process conditions for the conversion of Argemone mexicana oil to its methyl ester by transesterification required 1% manganese carbonate as catalyst with alcohol to oil ratio 5:1 at 60°C to yield biodiesel of 99.99% purity. The methyl esters obtained were examined by Gas chromatography analysis.
Źródło:
Polish Journal of Chemical Technology; 2012, 14, 1; 65-70
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solvent-free synthesis of 1-amidoalkyl-2-naphthol and 3-amino-1-phenyl-1H benzo[f]chromene-2-carbonitrile derivatives by Fe3O4@enamine-B(OSO3H)2 as an efficient and novel heterogeneous magnetic nanostructure catalyst
Autorzy:
Li, Fangping
Zhang, Jun
Wang, Longjiang
Liu, Weijian
Yousif, Qahtan A.
Powiązania:
https://bibliotekanauki.pl/articles/778863.pdf
Data publikacji:
2020
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
1-amidoalkyl-2-naphthol
3-amino-1-phenyl-1H benzo[f]chromene-2-carbonitrile
solvent-free conditions
magnetic
catalyst
Opis:
A green procedure for the one-pot three-component synthesis of 1-amidoalkyl-2-naphthol and 3-amino-1-phenyl-1H benzo[f]chromene-2-carbonitrile derivatives from the reaction of 2-naphtol, aldehydes, and malononitrile/acetamide in the presence of a catalytic amount of Fe3O4@enamine-B(OSO3H)2 as an efficient and novel heterogeneous magnetic nanostructure catalyst is described. The catalyst was characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). These strategies possess some merits such as simple work-up method, easy preparation of the catalyst, short reaction times, good-to-high yields, and non-use of hazardous solvents during all steps of the reactions. Moreover, due to the magnetic nature of the catalyst, it was readily recovered by magnetic decantation and can be recycled at least six runs with no considerable decrease in catalytic activity.
Źródło:
Polish Journal of Chemical Technology; 2020, 22, 2; 9-19
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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