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Tytuł:
Asymetryczne reakcje pericykliczne katalizowane kompleksami magnezu
Magnesium-catalyzed asymmetric pericyclic reactions
Autorzy:
Czombik, Anna
Powiązania:
https://bibliotekanauki.pl/articles/2200433.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
chiralność
kataliza asymetryczna
reakcja pericykliczna
kwas Lewisa
magnez
chirality
asymmetric catalysis
pericyclic reactions
Lewis acid
magnesium
Opis:
II Group-metals, like magnesium, are one of the most widespread elements in the environment. The abundance of II-group metals in the Earth’s crust is over 108 times greater than the precious metals. For the industrial applications, the important factors are the low costs of production and higher accessibility of their compounds. This puts the spotlight on alkaline-earth metals competing with transition elements as catalysts in organic synthesis. Features of their derivatives, like mild Lewis acidity and strong Brønsted basicity enabled them to catalyze reactions where Lewis-acidactivation of the substrate is essential. In this review the emphasis was put on magnesium-catalyzed pericyclic reactions, which are recognized as one of the most important methods of new carbon-carbon or carbon-heteroatom bonds formation. Using the catalysts based on II-group metal cations and chiral ligands, a highly stereoselective conversion of achiral substrates into enantioenriched products is possible. The Mg-based catalysts have been used in Diels-Alder, ene and 1,3-dipolar additions. Described synthesis methods were characterized by high efficiency (chemical yields and enantiomeric excesses). Where applicable, the relationships between the structure of catalyst/substrates, conditions and efficiency were discussed. Just now there are a few applications, for example in synthesis of alkaloid (–)-manzacidine or antibiotic of algal origin – (–)-malyngolide.
Źródło:
Wiadomości Chemiczne; 2022, 76, 9-10; 755--788
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:
CO2 zamiast CO : katalityczna konwersja CO2 w syntezie związków karbonylowych
CO2 instead of CO : catalytic conversion of CO2 in the synthesis of carbonyl compounds
Autorzy:
Wójcik, Ewelina
Trzeciak, Anna M.
Powiązania:
https://bibliotekanauki.pl/articles/1410899.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
ditlenek węgla
karbonylacja
kataliza
redukcja
silany
carbon dioxide
carbonylation
catalysis
reduction
silanes
Opis:
Modem industrial carbonylation processes, leading to functionalized carbonyl compounds, are based on the application of highly toxic and flammable carbon monoxide. Recently, carbon dioxide which is non-toxic and abundant, has attracted attention as a perfect C1 source to build new C-C and C-N bonds. From the standpoint of green and sustainable chemistry, it is appealing and challenging to combine the reduction of CO2 with subsequent carbonylation using in situ formed CO. Herein we present the application of CO2 as C1 building block for the carbonylation of different organic compounds in the presence of transition metal catalysts (e.g. Pd, Rh, Ru, Fe). Industrially important organic compounds has been obtained in hydroformylation, dehydrogenation, hydrogenation, aminocarbonylation and carboxylation reactions with CO2. On the other hand, rapid reduction of CO2 to CO could processed in the metal catalyst - free systems, using a catalytic amount of fluoride salt and stoichiometric amount of di- or hydrosilane. In these reactions silyl formate has been identified as an important intermediate formed from silane and carbon dioxide. Also hydrazine and sodium borohydrate have been used for CO2 reduction to formic acid or other products. Obviously, these reactions could be restricted because of their sensitivity to the applied conditions, high cost of reactants as well as the waste generated. The presented examples of catalytic carbonylation reactions with CO2 as a source of CO group illustrate a high technological potential of this strategy.
Źródło:
Wiadomości Chemiczne; 2021, 75, 3-4; 395-422
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Insight into the Catalytic Mechanism of MFe2O4 (M = Ni, Zn and Co) on the Thermal Decomposition of TKX-50
Autorzy:
Hou, Xiaoting
Zhang, Ming
Zhao, Fengqi
Yang, Yanjing
An, Ting
Li, Hui
Pan, Qing
Wang, Xiaohong
Zhang, Kun
Powiązania:
https://bibliotekanauki.pl/articles/27788010.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
bimetallic iron oxide
thermal decomposition
TKX-50
catalysis
mechanism
Opis:
Synthesized dihydroxylammonium 5,5’-bistetrazole-1,1’-diolate (TKX-50) owes its outstanding application prospects in the field of insensitive solid propellants not only to its high energetic performance but also to its low mechanical sensitivity. Based on the excellent catalytic activity of bimetallic iron oxides for the thermal decomposition of TKX-50, the catalytic mechanism of bimetallic iron oxides (NiFe2O4, ZnFe2O4 and CoFe2O4) for TKX-50 pyrolysis has been explored. For this study, the decomposition process of TKX-50, before and after mixing with the bimetallic iron oxides NiFe2O4, ZnFe2O4 and CoFe2O4 was monitored by in-situ FTIR and gas-phase MS-FTIR instruments. Of the different catalysts, ZnFe2O4 gave the best result for reducing the initial decomposition temperature of TKX-50. Additionally, the activation energy of functional group cleavage of TKX-50, before and after mixing with ZnFe2O4, was also calculated for mechanism analysis from the results of the in-situ FTIR measurements. The results showed that the condensate and the gas-phase decomposition products of TKX-50 remained unchanged after mixing with different catalysts, while the activation energy of tetrazole ring cleavage was significantly reduced. The results of this study will be helpful for the rational design of insensitive solid propellant formulations containing TKX-50, and for understanding the pyrolysis mechanisms of TKX-50 before and after mixing with the efficient catalyst ZnFe2O4.
Źródło:
Central European Journal of Energetic Materials; 2021, 18, 2; 223--244
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
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
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:
Kataliza przeniesienia międzyfazowego jako nowoczesna technika w syntezie organicznej
Phase-transfer catalysis as a modern technique in organic synthesis
Autorzy:
Siewniak, Agnieszka
Chrobok, Anna
Powiązania:
https://bibliotekanauki.pl/articles/1853730.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
kataliza przeniesienia międzyfazowego
czwartorzędowe sole amoniowe
poli glikole etylenowe
katalizatory chiralne przeniesienia międzyfazowego
phase-transfer catalysis
quaternary ammonium salts
polyethylene glycols
chiral phase-transfer catalysts
Opis:
Phase-transfer catalysis (PTC) has been already known for 60 years and has an established position both on a laboratory and industrial scale. It is an energy-saving technique, ensuring high yields and selectivity under mild conditions. PTC is successfully used, among others, in the pharmaceutical, polymer, agrochemical industries, for the production of dyes, fragrances and flavors, to name a few. Currently, the development of phase-transfer catalysis is focused mainly on the search for active catalysts as well as extending the scope of its applications. In particular, catalysts immobilized on an insoluble carrier, which can be easily separated from the reaction mixture and recycled many times, are of great interest. The growing demand for chiral compounds has resulted in the development of phase-transfer catalysts which, while retaining the advantages of conventional PTC, will allow to obtain a product with high enantiomeric excess. This work characterizes the phase-transfer catalysis and presents examples of its applications in organic synthesis.
Źródło:
Wiadomości Chemiczne; 2021, 75, 9-10; 1297-1315
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kompleksy platyny typu Markó zawierające n-heterocykliczne ligandy karbenowe O właściwościach supersterycznych
Markó-type platinum complexes containing bulky n-heterocyclic carbene ligands
Autorzy:
Bolt, Małgorzata
Żak, Patrycja
Powiązania:
https://bibliotekanauki.pl/articles/1413313.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
N-heterocykliczne ligandy karbenowe
kompleksy platyny
kataliza homogeniczna
hydrosililowanie
dimeryzacja
N-heterocyclic carbene ligands
platinum complexes
homogeneous catalysis
hydrosilylation
dimerization
Opis:
Progress in technology implying increasing demand for advanced materials dedicated for specific application has become a driving force stimulating research in different branches of science. It has been estimated that over 90% highly processed compounds have been obtained by the methods whose pivotal processes take place in the presence of catalysts based on transition metal complexes. Although these processes permit obtaining desired products, they are often charged with numerous drawbacks that prevent their implementation in industry. That is why the search for new catalytic systems ensuring high efficiency of final products and a possibility of reaction control is still an important direction of studies. Markó complexes are a group of platinum(0) coordination compounds of type [(NHC)Pt(dvtms)]. Although much attention has been recently attracted to these class of compounds, their number reported in hitherto literature is still limited. Owing to the possibility of wide modification of NHC carbene ligand attached to metal, the structures, and thus also properties, of the final complexes can be relatively easily matched to the requirements of individual catalytic reactions. It is particularly interesting in view of permanent development of new technologies and still increasing demand for new synthetic methods of more sophisticated materials dedicated to specific applications. In this paper, the synthesis and characterization of Markó type platinum(0) complexes containing bulky N-heterocyclic carbene ligands is described and their applications in the synthesis of new and unknown organic and organosilicon compounds are discussed. The main advantages of these complexes are highlighted providing an overview of this fascinating area of research.
Źródło:
Wiadomości Chemiczne; 2021, 75, 1-2; 31-53
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synteza i zastosowanie styrylopochodnych arenów, karbazolu i ferrocenu w projektowaniu e-stereoregularnych krzemoorganicznych materiałów hybrydowych
Synthesis and application of styryl derivatives of arenes, carbazol and ferrocene for designing e-stereoregular organosilicon hybrid materials
Autorzy:
Majchrzak, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/1413279.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
kataliza
sprzęganie Suzuki
sililujące sprzęganie
materiały hybrydowe
polimery
catalysis
Suzuki coupling
silylative coupling
hybrid materials
polymers
Opis:
The potential for expanding the variety of catalytic methods for carbon-carbon bond formation is being currently explored in many research centres all over the world. An increasing use of selected d-block metals as catalysts in the synthesis has brought new methods of functionalization of organic and organometallic compounds of great importance for development of polymer chemistry and organic chemical technology [5, 6]. This work describes very precise and controlled catalytic transformations as useful tools for the synthesis of new E-conjugated organic, organosilicon molecular and polymeric compounds. The combination of Suzuki-Miyaura coupling and silylative coupling reactions as a simple and efficient method is established for designing new E-stereoregular hybrid materials in the presence of well-defined transition metal (TM) catalysts. All presented compounds can be interesting precursors for a further functionalization that may significantly increase the possibility of their application in the design and synthesis of new functional materials.
Źródło:
Wiadomości Chemiczne; 2021, 75, 1-2; 137-162
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie zielonych rozpuszczalników w syntezie nienasyconych związków boro- i krzemoorganicznych na drodze reakcji hydrometalacji i sprzęgania Marcińca
Application of green solvents in the synthesis of unsaturated organoboron and organosilicon compounds via catalytic hydrosilylation and Marciniec coupling reactions
Autorzy:
Walkowiak, Jędrzej
Powiązania:
https://bibliotekanauki.pl/articles/1413280.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
hydrometalacja
reakcja sprzęgania
CO2 w stanie nadkrytycznym
ciecze jonowe
poli(glikol etylenowy)
PEG
kataliza homogeniczna
hydrometallation
coupling reaction
supercritical CO2
ionic liquids
poly(ethylene glycol)
homogeneous catalysis
Opis:
Unsaturated organoboron and organosilicon compounds constitute an important class of organometallic compounds, which due to the presence of silyl- or boryl- group attached to Csp2 atoms, their simple and straightforward transformations in coupling and demetallation reactions, found a broad range of applications in the synthesis of fine chemicals or new materials with tailored properties. Such compounds might be synthesized in many transformations but two of them: hydrometallation and Marciniec coupling reactions permitted to obtain compounds with high effectivity, selectivity, and in the case of hydrometallation reactions with excellent atom economy. Most of these processes occur in a homogeneous phase, which ensures excellent yields and stereo- and regioselectivity. On the other hand, such conditions generate problems with catalyst reuse, product separation, and substantial consumption of toxic, volatile organic solvents. According to the assumptions of sustainable development in chemistry, the new procedures, which allow to intensify the process in terms of its efficiency, according to green chemistry rules are of prior importance in modern chemical industry. In this manuscript, the newest achievements in the application of green solvents (ionic liquids, liquid polymers, and supercritical CO2) in catalytic hydrometallation of alkynes and coupling of vinylmetalloids with olefins are discussed. Such an approach builds a new strategy for effective catalyst immobilization and its reuse, the increase of process productivity by the application of repetitive batch processes, and elimination of organic solvents, typically used in these transformations. Selected contributions in this field of chemistry are presented within this review.
Źródło:
Wiadomości Chemiczne; 2021, 75, 1-2; 111-136
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charakterystyka struktury elektronowej heteropolikwasu fosforowolframowego H3PW12O40 modyfikowanego kationem Fe2+
The electronic structure of phosphotungstic (H3PW12O40) heteropolyacids modified by Fe2+ cation
Autorzy:
Niemiec, Piotr Jan
Powiązania:
https://bibliotekanauki.pl/articles/1402364.pdf
Data publikacji:
2020
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Tarnowie
Tematy:
heteropolikwasy
DFT
analiza strukturalna
heteropolyacids
density functional theory
electronic structure
catalysis
NOCV-SR
Opis:
W pracy zbadano wpływ podstawienia atomu wolframu atomem żelaza w pierwszorzędowej strukturze heteropolikwasu fosforowolframowego o budowie anionu Keggina. Charakterystykę struktury elektronową zmodyfikowanego heteropolikwasu przeprowadzono za pomocą: analizy populacyjnej NBO, całkowitych (PDOS) i parcjalnych (PDOS) widm gęstości stanów, energetyki i charakteru chemicznego orbitali granicznych (HOMO/LUMO) oraz rozmiaru przerwy wzbronionej (gap). Dodatkowo zbadano mechanizm oddziaływania modyfikowanego kationem Fe2+ heteropolikwasu fosforowolframowego z cząsteczką H2O pełniącą rolę środowiska reakcji chemicznej. W większości charakterystyk stwierdzono istotny wpływ wprowadzonego metalu przejściowego na ww. właściwości w stosunku do heteropolikwasu wyjściowego H3PW12O40.
In this paper the influence of substituting the tungsten atom with an iron ion in the primary structure of the phosphotungstic heteropolyacid with the Keggin anion structure was investigated. Characterization of the electronic structure of the modified heteropolyacid was performed using: population analysis according to NBO scheme, total (TDOS) and partial (PDOS) density of states spectra, energy and chemical character of frontier orbitals (HOMO / LUMO) and the size of the HOMO-LUMO band gap. Additionally, the mechanism of interaction between the Fe2+ with H2O molecule, acting as a chemical reaction medium, was investigated. Most cases showed a significant effect of the introduced transition metal ion (Fe2+) on the above-mentioned properties in relation to the nonmodified heteropolyacid H3PW12O40.
Źródło:
Science, Technology and Innovation; 2020, 11, 4; 24-32
2544-9125
Pojawia się w:
Science, Technology and Innovation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Study on NH3-SCR of High Entropy Mineral Catalytic Materials for Different Ratios of Rare Earth Concentrate/Rare Earth Tailing
Autorzy:
Meng, Zhaolei
Zhu, Chao
Wang, Jian
Wu, Wenfei
Powiązania:
https://bibliotekanauki.pl/articles/778344.pdf
Data publikacji:
2020
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
rare earth concentrate
rare earth tailings
catalytic denitrification
modification
mineral catalysis
Opis:
A series of high-entropy mineral catalytic materials were obtained by mixing rare earth tailings containing Fe oxide and rare earth concentrate rich in Ce in Baiyun Obo in different proportions, and by acid-base leaching and microwave roasting. The effects of different proportions of mixed rare earth minerals on the denitrification activity of the samples were analyzed by various techniques, including XRD, EDS and SEM. The mineral phase structure and surface morphology of the catalysts were analyzed. The surface properties of the samples were tested by TPD and XPS methods. The denitrification activity of the sample was simultaneously evaluated and compared in the microreactor. The results show that the denitration efficiency of the active powder is the best when the mixing ratio of rare earth tailings/rare earth concentrate is 1:1, the denitration rate can reach 82%. In summary, different proportions of optimization are extremely effective methods to improve catalyst performance.
Źródło:
Polish Journal of Chemical Technology; 2020, 22, 3; 70-78
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
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
Tytuł:
Katalizatory palladowe immobilizowane w materiałach typu MOF aktywne w reakcjach uwodornienia
Palladium catalysts immobilized in MOF materials active in hydrogenation reactions
Autorzy:
Augustyniak, Adam W.
Trzeciak, Anna M.
Powiązania:
https://bibliotekanauki.pl/articles/172135.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
sieci metaliczno-organiczne
kataliza
pallad
uwodornienie
selektywność
metal-organic frameworks
catalysis
palladium
hydrogenation
reaction
selectivity
Opis:
Palladium immobilized in metal-organic frameworks (MOF) exhibit promising catalytic properties in hydrogenation of different unsaturated substrates. Due to the specific porous and crystalline structure MOFs can contribute in bonding and activation of organic substrates, increasing catalytic efficiency of Pd@MOF composites. The superior tunability of MOFs structures enables to design highly selective catalysts for hydrogenation of different substrates, such as olefins, esters, ketones, alcohols or alkynes. Due to the synergistic effects of palladium and MOF not only high activity but also high selectivity can be achieved. The article presents representative examples of MOF-based palladium catalysts for hydrogenation to illustrate perspectives, also technological, of their application.
Źródło:
Wiadomości Chemiczne; 2019, 73, 3-4; 221-241
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Możliwości pracy z osobami wykluczonymi społecznie w inkluzyjno-katalaktycznym modelu w procesie reintegracji społecznej
Possibilities for people with social disabilities
Autorzy:
Kieszkowska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/1811083.pdf
Data publikacji:
2019
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II. Towarzystwo Naukowe KUL
Tematy:
wyrównywanie szans
wymiana społeczna – katalaktyka
reintegracja społeczna
inkluzja społeczna
koncepcja reorganizacji społecznej
equal opportunities
social exchange – catalysis
social reintegration
social inclusion
the concept of social reorganization
Opis:
Za zintegrowany można uznać ten system społeczny, w którym cele wyznaczane przez daną kulturę są w pełni akceptowane przez jednostki i osiągane za pomocą społecznie uznanych, zinstytucjonalizowanych środków z uwzględnieniem pracy określonych grup specjalistów. Wysoki poziom integracji społecznej charakteryzuje się intensywnością kontaktów między członkami danej zbiorowości, układem trwałych więzi społecznych spajających jednostki i grupy oraz ukształtowaną świadomością identyfikacji i łączności między nimi. Programy profilaktyczne, readaptacyjne, reintegracyjne lub doskonalące funkcjonowanie systemu społecznego dla określonej grupy czy środowiska społecznego powinny wychodzić od najniższego poziomu, czyli konkretnych osób uwikłanych w problemy społeczne i społeczeństwa, aby zmienić ich sposób myślenia i wartościowania, wzajemnego funkcjonowania i uczestnictwa w danym systemie. Przekształcenie sposobów działania jednostki lub grupy może wynikać z przemiany wewnętrznej lub oznaczać zewnętrzne dostosowanie się do zmienionych warunków działania, nie naruszając w istotny sposób dotychczasowego kształtu struktury wewnętrznej podmiotu. Obie możliwości, tzn. zmiana zachowania wynikająca ze zmiany wartości i poglądów oraz instrumentalna zmiana zachowań przy utrzymaniu dotychczasowych wartości i przekonań, wyznaczają dwa krańce kontinuum adaptacji społecznej, w tym również readaptacji społecznej jako ponownego przystosowania jednostki będącej w izolacji do pełnego samodzielnego, aktywnego i wartościowego życia według warunków i zasad społeczno-moralnych panujących w środowisku lokalnym. Działania reintegracyjne, w tym również samopomocowe, mają na celu odbudowanie i podtrzymywanie umiejętności uczestniczenia w życiu społeczności lokalnej i przyjęciu nowych, akceptowanych ról społecznych w miejscu pracy, zamieszkania lub pobytu na zasadzie wymiany dóbr materialnych i niematerialnych. Wymiana społeczna oparta na odpowiedzialności za drugiego człowieka, zaufaniu, prawie do wyboru i zaciągania zobowiązań stanowi szansę dla wykluczonych społecznie w odnajdywaniu własnych zasobów i potencjałów w warunkach środowiska otwartego. W myśl catallaxy bycie członkiem społeczeństwa oznacza nie tylko ekonomiczną wymianę poprzez wytwarzanie określonych dóbr, ale także przyjmowanie do społeczności jako pełnoprawnego obywatela i podejmowanie ważnych i odpowiedzialnych zadań w społeczności.
Entering re-adaptation programs until recently aroused some concerns and lack of skills of their implementation, which after some time, at least in the belief that prison staff raises greater understanding and motivation to implement. It is likely that in the near future, those who are excluded, and returning to society, they can have a sense of freedom, the responsibility for their actions. Prevention programs, readaptation, reintegration or improving the functioning of the social system for a specific group or social environment should Reaching-you generously from the lowest level, or individuals involved in social issues and society to change their way of thinking and evaluating, mutual functioning and participation in a given system. The transformation of modes of action of individuals or groups may result from the transformation of the inner or outer mean to adapt to changing conditions without affecting significantly the current shape of the internal structure of the entity. Both options, ie. Change in behavior resulting from changes in the values and beliefs and the instrumental behavior change while maintaining the existing values and provi-Konan nominate two ends of a continuum of social adaptation, including social reintegration as a readjustment in the entity being in isolation to fully autonomous, active and valuable life according to the terms and conditions of socio-moral prevailing in the local environment. Reintegration activities, including self-help, they have to build and maintain skills for participation in the local community and the adoption of new acceptable social roles in the workplace, residence or domicile in an exchange of tangible and intangible. Exchange-based social responsibility for another human being, trust, the right to choose and commit represents an opportunity for socially excluded people in finding their own resources and potentials within the open environmental conditions. In thought catalaxy being a member of society means not only economic exchange through the production of certain goods, but also accepting the community as a full citizen and make important and responsible tasks in the community.
Źródło:
Roczniki Pedagogiczne; 2019, 11(47), Numer specjalny; 229-256
2080-850X
Pojawia się w:
Roczniki Pedagogiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
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