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Wyszukujesz frazę "heterogeneous catalysis" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Kataliza heterogeniczna
Autorzy:
Rachwalik, R.
Ogonowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/273835.pdf
Data publikacji:
2010
Wydawca:
Roble
Tematy:
kataliza heterogeniczna
katalizatory heterogeniczne
jonon
heterogeneous catalysis
heterogeneous catalysts
ionium
Źródło:
LAB Laboratoria, Aparatura, Badania; 2010, 15, 2; 19-26
1427-5619
Pojawia się w:
LAB Laboratoria, Aparatura, Badania
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:
Kataliza procesów hydrosililowania z udziałem cieczy jonowych
Catalysis of hydrosilylation processes with the participation of ionic liquids
Autorzy:
Bartlewicz, Olga
Szymańska, Anna
Jankowska-Wajda, Magdalena
Dąbek, Izabela
Maciejewski, Hieronim
Powiązania:
https://bibliotekanauki.pl/articles/1413312.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
hydrosililowanie
kompleksy Rh
kompleksy Pt
ciecze jonowe
SILPC
kataliza heterogeniczna
hydrosilylation
Rh complexes
Pt complexes
ionic liquids
heterogeneous catalysis
Opis:
Hydrosilylation is a fundamental and elegant method for the laboratory and industrial synthesis of organosilicon compounds. The hydrosilylation reaction is usually performed in a single-phase homogeneous system. A major problem, particularly in homogeneous catalysis, is the separation of catalyst from the reaction mixture. The presence of metals in the reaction products, even in trace quantities, is unacceptable for many applications, therefore efforts have been made at applying heterogeneous catalysts or immobilised metal complexes in order to obtain high catalytic activity and easy product isolation at the same time. One of the methods for producing such catalysts is the employment of ionic liquids as agents for the immobilization of metal complexes. Biphasic catalysis in a liquid-liquid system is an ideal approach through which to combine the advantages of both homogeneous and heterogeneous catalysis. The ionic liquids (ILs) generally form the phase in which the catalyst is dissolved and immobilized. In our research we have obtained a number of catalytic systems of such a type which were based on rhodium and platinum complexes dissolved in phosphonium, imidazolium, pyridinium and ammonium liquids. Currently, there has a common trend to obtain heterogenized systems that combine advantages of homogeneous and heterogeneous catalysis, which makes the hydrosilylation process more cost- effective. Such integration of homo- and heterogeneous catalysts is realized in several variants, as supported IL phase catalysts (SILPC) and solid catalysts with ILs layer (SCILL). Although all the above systems show high catalytic activities, their structure is unknown. This is why we have made attempts to modify selected ionic liquids (corresponding to our most effective systems) and we have applied them as ligands in the synthesis of platinum and rhodium complexes. Another group of catalysts comprises anionic complexes of rhodium and platinum which were obtained by reactions between halide complexes of metals and a respective ionic liquid. Most of the obtained complexes are solids insoluble in hydrosilylation reagents and are characterized by a high catalytic activity. A considerable development of heterogeneous catalysts of this type and their application in many hydrosilylation processes can be expected in the future. This mini-review briefly describes the recent progress in the design and development of catalysts based on the presence of ionic liquids and their applications for hydrosilylation processes.
Źródło:
Wiadomości Chemiczne; 2021, 75, 1-2; 5-29
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Catalyst regeneration techniques in naphtha reforming: Short review
Autorzy:
Gupta, Aviral
Gupta, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/2173419.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heterogeneous catalysis
regeneration
naphtha reforming
catalyst reactivation
non-linear
modelling
kataliza heterogeniczna
regeneracja
reformowanie benzyny ciężkiej
reaktywacja katalizatora
modelowanie
Opis:
Catalytic reforming is an important intermediate in the processing of crude (naphtha in particular) to obtain gasoline. The catalyst used in the process (platinum) is quite expensive and may negatively impact the business if not used judiciously. The aforesaid not only refers to the reduction in loss of the catalyst per unit of gasoline produced but also to the manufacturing of an environmentally friendlier product alongside which is the need of the planet and also a necessity to meet the increasingly strict government norms. In order to meet the above requirements, various refineries around the world use various well-known conventional methods which depend on the quality and quantity of crude manufactured by them. This paper focuses on highlighting recent advancements in methods of catalytic regeneration (CR) in the reforming unit of petroleum industries to produce high octane gasoline, without any major replacements in their existing setup. Research papers formulated by the application of methodologies involving non-linear models and real-time refinery data have only been considered to avoid any deviations/errors in practical applications. In-depth analysis of these papers has led to the origin of some ideas which have been included as suggestions and can be considered as subjects of further research. In all, the objective of the paper is to serve as a reference for researchers and engineers working on devising optimum methods to improve the regeneration of reforming catalysts.
Źródło:
Chemical and Process Engineering; 2022, 43, 2; 101--108
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elementary steps in heterogeneous catalysis: The basis for environmental chemistry
Podstawowe kroki w katalizie heterogennej: Podstawy dla chemii środowiska
Autorzy:
Ertl, G.
Zielińska, M.
Rajfur, M.
Wacławek, M.
Powiązania:
https://bibliotekanauki.pl/articles/106550.pdf
Data publikacji:
2017
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
heterogeneous catalysis
environmental chemistry
oxidation of carbon monoxide
synthesis of ammonia
kataliza heterogenna
chemia środowiska
utlenianie tlenku węgla
synteza amoniaku
Opis:
Catalysis is an alternative way for reaching an immediate formation of a product, because of a lower energy barrier (between the molecules and the catalysts). Heterogeneous catalysis comprises the acceleration of a chemical reaction through interaction of the molecules involved with the surface of a solid. It is a discipline, which involves all the different aspects of chemistry: inorganic and analytical chemistry in order to characterize the catalysts and the forms of these catalysts. The industrial chemistry puts all these things together to understand the solid chemical handling, chemical reaction and energy engineering and the heat and mass transfer in these catalytic processes. Very often there are more than one, but several products, then the role of the catalyst is not so much related to activity, but to selectivity. The underlying elementary steps can now be investigated down to the atomic scale as will be illustrated mainly with two examples: the oxidation of carbon monoxide (car exhaust catalyst) and the synthesis of ammonia (the basis for nitrogen fertilizer). There is a huge market for the catalysts themselves despite of their high costs. A large fraction is used for petroleum refineries, automotive and industrial cleaning processes. The catalytic processes is a wide field and there are still many problems concerning energy conservation and energy transformation, so there is much to do in the future.
Kataliza stała się obecnie alternatywnym sposobem na natychmiastowe tworzenie produktu chemicznego z uwagi na niższą barierę energetyczną (między cząsteczkami a katalizatorami). Kataliza heterogenna obejmuje przyspieszenie reakcji chemicznej poprzez oddziaływanie cząsteczek związanych z powierzchnią ciała stałego. Jest to dyscyplina, która obejmuje różne aspekty chemii: chemię nieorganiczną i analityczną w celu scharakteryzowania katalizatorów i form tych katalizatorów. Chemia przemysłowa następnie łączy te wszystkie zagadnienia razem, aby zrozumieć chemiczną manipulację ciał stałych, reakcję chemiczną i inżynierię energetyczną oraz przenoszenie ciepła i masy w tych procesach katalitycznych. Bardzo często tworzy się nie jeden, lecz kilka produktów, wtedy rola katalizatora nie jest tak bardzo związana z aktywnością, ale z selektywnością. Podstawowe etapy można teraz zbadać w skali atomowej, co będzie zilustrowane głównie dwoma przykładami: utlenianiem tlenku węgla (katalizator spalin samochodowych) i syntezą amoniaku (podstawa nawozu azotowego). Istnieje ogromny rynek katalizatorów pomimo wysokich ich kosztów. Duża ich część jest stosowana w samochodach, w rafineriach ropy naftowej i przemysłowych procesach czyszczenia. Procesy katalityczne stanowią szeroki obszar badań i nadal istnieją liczne problemy związane z oszczędzaniem i transformacją energii.
Źródło:
Chemistry-Didactics-Ecology-Metrology; 2017, 22, 1-2; 11-41
2084-4506
Pojawia się w:
Chemistry-Didactics-Ecology-Metrology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Functional materials based on carbon : encapsulated iron nanoparticles
Materiały funkcjonalne oparte na magnetycznych nanokapsułkach węglowych
Autorzy:
Kasprzak, Artur
Popławska, Magdalena
Koszytkowska-Stawińska, Mariola
Powiązania:
https://bibliotekanauki.pl/articles/2057908.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
nanomateriały węglowe
magnetyczne nanokapsułki węglowe
nanomedycyna
elektrochemia
kataliza heterogeniczna
adsorpcja
carbon nanomaterials
carbon-encapsulated iron nanoparticles
nanomedicine
electrochemistry
heterogeneous catalysis
adsorption
Opis:
The chemistry of carbon nanomaterials attracts continuous attention of scientists because of their promising properties and applications. Carbon-encapsulated iron nanoparticles (CEINs) are subgroup of carbon nanomaterials. CEINs are the core-shell nanostructures including the metallic phase permanently encapsulated in a tight carbon coating. The carbon shell protects CEINs against oxidation of metal into a corresponding oxide, as well as prevents them from spontaneous aggregation. It has been documented that the magnetic properties of CEINs are superior in comparison with the respective materials comprising metal oxides. Additionally, the presence of the carbon shell enables surface functionalization of CEINs by means of various synthetic routes, both covalent and non-covalent ones. Chemical functionalization enables tuning the materials’ properties and applications, for example toward introducing catalytically active sites or improving colloidal stability. One may conclude that CEINs combine physicochemical properties of graphene and iron nanoparticle. Therefore, this is prospective material for many applications. In this article, we discuss the properties, chemistry and selected applications of CEINs.
Źródło:
Wiadomości Chemiczne; 2021, 75, 11-12; 1211--1233
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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