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    Wyświetlanie 1-15 z 15
    Tytuł:
    Sililujące sprzęganie : użyteczne narzędzie selektywnej syntezy organicznej
    Silylative coupling : a useful tool for selective organic synthesis
    Autorzy:
    Pawluć, Piotr
    Zaranek, Maciej
    Powiązania:
    https://bibliotekanauki.pl/articles/1413309.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    sililujące sprzęganie
    zastosowanie w syntezie organicznej
    silylative coupling
    application in organic synthesis
    Opis:
    The design and development of highly selective methods for the synthesis of functionalized olefins based on sequential catalytic reactions using organosilicon reagents have been the subject of extensive study because of their versatile application in organic and organometallic synthesis. The ruthenium-catalyzed silylative coupling of olefins with vinyl-substituted organosilicon compounds (discovered by professor Bogdan Marciniec and co-workers in Poznań) represents one of the most efficient methods for the synthesis of stereodefined alkenylsilanes and isomeric bis(silyl)alkenes, which are particularly attractive scaffolds for further transformations including palladium-catalyzed cross-coupling with organic halides (Hiyama coupling) or substitution with organic and inorganic electrophiles. The unique feature of these methodologies is that the stereochemistry of the overall processes can be controlled during the initial step as the subsequent desilylation usually proceeds with retention of the configuration at the carbon atom and allows the formation of stereodefined products. The sequential silylative coupling - Hiyama coupling has been successfully used for stereoselective synthesis of (E)-stilbenes, bis-(E)-styrylarenes, stilbenoid dendrimers and poly(arylene-vinylene)s. On the other hand, the combination of silylative coupling with electrophilic halodesilylation reaction has been applied for the selective preparation of synthetically useful alkenyl halides (e.g. (E)-styryl halides, (E)-N-2-iodovinylcarbazole, (E)-N-2-iodovinylamides) - versatile coupling partners in palladium-catalyzed Suzuki and Sonogashira couplings, leading to vide variety of stereodefined ß-substituted (E)-enimides, (E,E)-dienimides and (E)- enynimides as well as related л-conjugated derivatives of N-substituted carbazole. The discovery of sequential silylative coupling and rhodium- or iridium-catalyzed acylation reactions is of great importance in the synthesis of (E)-α,ß-unsaturated ketones. The article highlights recent developments and covers literature mainly from the last decade in the sequential (also one-pot) synthetic strategies including ruthenium-catalyzed silylative coupling followed by desilylative cross-coupling, acylation and halogenation, leading to stereodefined я-conjugated organic derivatives which are widely applied as fine chemicals, functional materials or building blocks in organic synthesis.
    Źródło:
    Wiadomości Chemiczne; 2021, 75, 1-2; 93-110
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Donorowo-akceptorowe struktury oligopirolowe : projektowanie, synteza i właściwości
    Donor-acceptor oligopyrroles : design, synthesis, and properties
    Autorzy:
    Stępień, Marcin
    Powiązania:
    https://bibliotekanauki.pl/articles/1409858.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    pirol
    układy donorowo-akceptorowe
    chromofory
    synteza
    pyrrole
    donor-acceptor systems
    chromophores
    organic synthesis
    Opis:
    The review summarizes one decade of research carried out in the Stępień Laboratory at the University of Wrocław. We focus on the group’s contributions to pyrrole chemistry, notably the development of donor-acceptor pyrrole hybrids and their use as building blocks in the synthesis of porphyrins, small-molecule dyes, and nanographene analogues.
    Źródło:
    Wiadomości Chemiczne; 2021, 75, 5-6; 593-602
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mikrofale w syntezie organicznej: historia i perspektywy
    Autorzy:
    Lipińska, T. M
    Powiązania:
    https://bibliotekanauki.pl/articles/273516.pdf
    Data publikacji:
    2013
    Wydawca:
    Roble
    Tematy:
    mikrofale
    promieniowanie mikrofalowe
    technika mikrofalowa
    synteza organiczna
    microwaves
    microwave radiation
    microwave techniques
    organic synthesis
    Źródło:
    LAB Laboratoria, Aparatura, Badania; 2013, 18, 4; 6-10
    1427-5619
    Pojawia się w:
    LAB Laboratoria, Aparatura, Badania
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kwas winowy i jego pochodne we współczesnej chemii organicznej
    Tartaric acid and its derivatives in current organic chemistry
    Autorzy:
    Grajewski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/171622.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    kwas winowy
    winiany
    stereochemia
    synteza organiczna
    kataliza
    tartaric acid
    tartrates
    stereochemistry
    organic synthesis
    catalysis
    Opis:
    The tartaric acid and its salts have been present in chemistry for almost 350 years, since Pierre Seignette isolated Rochelle salt in 1675. Since that time tartaric acid and its derivatives have been often used in chemistry due to their accessibility, enantiopurity, relatively low cost and presence of different functional groups which easily allow to modify the molecule. Many tartaric acid derivatives serve as catalysts in important stereoselective transformations such as Sharpless asymmetric epoxidation or asymmetric Rousch aryloboronation. In many others reactions tartaric acid have been employed as a chiral building block for natural products synthesis, highly functionalized molecules or ligand design such as well known TADDOL or its analogues. Its polar functional groups allow to form crystals with amines and aminoalcohols what is widely used for their enantiopurification and resolution. The relatively new subdiscipline is the use of tartaric acid in chiral recognition and chiral discrimination in nanochemistry and enantioselective chromatography. The other, recent applications of tartaric acid include functionalization of metal layers, antibacterial and antifungal activity among many others. The significance of tartaric acid is evident – since 2000, words “tartaric acid” or “tartrates” can be found in databases over four thousand times. Taking that into account this short review is concentrated on selected applications of tartaric acid and its derivatives in organic chemistry in recent several years.
    Źródło:
    Wiadomości Chemiczne; 2013, 67, 5-6; 495-519
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zastosowania enzymów z tkanek zwierzęcych w syntezie organicznej i biokatalizie. Część I. Hydrolazy
    Applications of hydrolases from animal tissues in organic synthesis
    Autorzy:
    Hibner, H.
    Ostaszewski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/172016.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    enzymy zwierzęce
    biokataliza
    synteza organiczna
    zastosowania hydrolaz
    animal enzymes
    biocatalysis
    organic synthesis
    applications of hydrolases
    Opis:
    This work presents systematically enzymes which can be obtained form animal tissue and their applications in synthesis of pharmaceuticals and nonracemic organic compounds. It lays out similarities in procedures of isolation and purification of particular enzymes. Such procedures usually are so simple that they can be used in every industrial or research laboratory. Most animal enzymes are well-investigated and their structures and substrate specificity are known. They are used as biocatalysts in many chemical processes. Others were used in one or a few reactions but their natural substrates and biochemical properties are described. Trials of predicting potential applications of such enzymes and other substrates for them were done. In this part typical applications of hydrolases: lipases (porcine pancreatic lipase [8–17], lamb pregastric lipase [22]), esterases (porcine, horse liver esterase, liver acetone powders [34–43, 46]), L-aminoacylase [48, 49], pepsin [56], trypsin [58, 59], imidase [52, 53], aldohexose hydrolases [60, 62-64], nucleotide pyrophosphatase [65]; were described. Also examples of immobilized [10, 32] or recombined [49] enzymes are given in the text. These modifications enhance catalytic properties or reduce costs of using enzymes. In practical applications a biocatalytic effect of enzymes from animal sources is often compared with microbial ones. This text is focused on processes where animal enzymes gave much better results (yield and enantioselectivity) than microorganisms. They are also proper, unlike whole microorganisms, to investigate and computer analysis of mechanism of the reaction. Enzymes isolated from animal tissues usually have well-defined structure of active site which is a key to predict mechanisms.
    Źródło:
    Wiadomości Chemiczne; 2011, 65, 7-8; 557-583
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zastosowania wybranych enzymów z tkanek zwierzęcych w syntezie organicznej i biokatalizie. Część II. Oksydoreduktazy, transferazy, liazy, izomerazy
    Applications of enzymes from animal tissues in organic synthesis, Part 2
    Autorzy:
    Hibner, H.
    Ostaszewski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/172018.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    enzymy zwierzęce
    biokataliza
    synteza organiczna
    zastosowania enzymów
    animal enzymes
    biocatalysis
    organic synthesis
    application of enzymes
    Opis:
    This work shows systematically known types of animal enzymes and their applications in synthesis of pharmaceuticals and nonracemic organic compounds. It lays out similarities in procedures of isolation and purification of particular enzymes. Such procedures usually are so simple that they can be used in every industrial or research laboratory. Most animal enzymes are well-investigated and their structures and substrate specificity are known. They are used as biocatalysts in many chemical processes. Others were used in one or a few reactions but their natural substrates and biochemical properties are described. Trials of predicting potential applications of such enzymes and other substrates for them were performed. Typical applications of: – Oxidoreductases: horse liver alcohol dehydrogenase [3–13], lactate dehydrogenase [16–18], glutamate dehydrogenase [19, 20], carbonyl reductase [24], catalase [27]; – Transferases: transaldolase [29], galactosyltransferase [30], UDP-glucuronosyltransferase [31], fucosyltransferase [34], farnesyl diphosphate synthase [35]; – Lyases: DOPA decarboxylase [38, 39], aldolase [42]; – Isomerases: N-acyl-D-glucosamine 2-epimerase [44] were described. Also examples of or recombined [24, 39, 44] enzymes are given in the text. These modifications enhance catalytic properties or reduce costs of using enzymes. In practical applications a biocatalytic effect of enzymes from animal sources is often compared with microbial ones. This text is focused on processes where animal enzymes gave much better results (yield and enantioselectivity) than microorganisms. They are also proper, unlike whole microorganisms, to investigate and computer analysis of mechanism of the reaction. Enzymes isolated from animal tissues usually have well-defined structure of active site which is a key to predict mechanisms. A quantitative analysis of applications of these enzymes was performed. Among animal enzymes hydrolases and oxidoreductases have found the most applications in synthesis. Transferases are also often used. Other classes of enzymes seldom act as biocatalysts. It is general tendency, true also in relation to microbial and plant enzymes.
    Źródło:
    Wiadomości Chemiczne; 2011, 65, 7-8; 585-607
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Biokatalityczne metody otrzymywania nieracemicznych alkoholi aryloallilowych
    Biocatalytic methods for preparation of nonracemic arylallylic alcohols
    Autorzy:
    Szymkuć, S.
    Ostaszewski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/172469.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    biokataliza
    nieracemiczne alkohole aryloallilowe
    synteza organiczna
    enzymy
    mikroorganizmy
    biocatalysis
    nonracemic arylallylic alcohols
    organic synthesis
    enzymes
    microorganisms
    Opis:
    Different methods for preparing nonracemic arylallylic alcohols are presented in this work. A key feature was an application the biocatalyst as a mean to obtain final products. These compounds play an important role in pharmaceutical industry, because they are substrates in the synthesis of various important therapeutics [1–3]. Methods presented in this work are divided into five main groups: 1. enantioselective hydroxylation, 2. microbiological deracemization, 3. enzymatic kinetic resolution, 4. enzymatic dynamic kinetic resolution, 5. enantioselective reduction. First two methods use only microorganisms like bacteria [4, 5, 10], fungi [6–8] or yeasts [11] as biocatalysts. Owing to the metabolic processes in the cells it was possible to obtain nonracemic arylallylic alcohol (results for method 2 are presented in Table 1). Unfortunately, the data were insufficient to create direct correlation between values of enantiomeric excess and types of applied microorganisms. Methods 3 and 4 used only isolated enzymes as biocatalysts. They belong to two classes: hydrolases and oxidoreductases. Oxidoreductases were used in the enzymatic kinetic resolution based on the enantioselective oxidation [28] of one enantiomer of the racemic arylallylic alcohol. Nevertheless, hydrolases [12–27], mainly lipases, isolated from microorganisms are enzymes of common use in enzymatic kinetic resolution. Owing to this method it was possible to obtain final products with excellent enantioselectivity (results are presented in Tables 2 and 3). Because kinetic resolution and dynamic kinetic resolution are related processes, in most cases similar enzymes are used. The choice of lipases as biocatalysts for method 4 was caused by the fact that they are able to catalyze enantioselective transesterification of arylallylic alcohols or their acetates. Furthermore, racemization is very important factor for efficacy of dynamic kinetic resolution processes. In most cases they are catalyzed by different types of complexes based on palladium [30, 31] and ruthenium [32, 34]. Final products prepared by this method had very high enantiomeric excesses and yields up to 93% (results are presented in Tables 4 and 5). The only method, presented in this work, that allowed to use both enzymes [39–41] and microorganisms [35–38] as biocatalysts, was enantioselective reduction. This method allows to obtain nonracemic arylallylic alcohols with excellent enantiomeric excess and yields up to 85% (results are presented in Table 6). In summary, all methods presented in this work show the advantages of biocatalysis as an alternative route to traditional chemical method
    Źródło:
    Wiadomości Chemiczne; 2012, 66, 1-2; 93-118
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Anion alkoksyallenowy w syntezie związków naturalnych i ich analogów
    Alkoxyallene anion in the synthesis of natural products and their analogues
    Autorzy:
    Busiak, B.
    Utecht, G.
    Jasiński, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/172377.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    alkoksyalleny
    addycja nukleofilowa
    synteza organiczna
    związki naturalne
    związki heterocykliczne
    alkoxyallenes
    nucleophilic addition
    organic synthesis
    natural products
    heterocycles
    Opis:
    Among diverse systems containing multiple bonds, cumulenes are recognized as the most reactive derivatives towards both nucleophilic and electrophilic agents, and for this reason, they are considered as important class of substrates for organic synthesis. Over the last three decades alkoxyallenes have been demonstrated as highly useful C3-building blocks for the construction of numerous N-, O-, and S-containing heterocycles, including enantiomerically pure compounds. Special attention has been paid to lithiated alkoxyallenes as suitable nucleophiles for the reactions with alkyl halides, strained heterocycles, carbonyl compounds and their derivatives. The presence of the allene unit in the initially formed adducts opens up several possibilities in the preparation of more complex systems. In this review, selected applications of lithiated alkoxyallenes in the synthesis of natural products and their analogues are discussed.
    Źródło:
    Wiadomości Chemiczne; 2016, 70, 1-2; 3-23
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Bezpośrednia synteza azydków i tioli organicznych pochodnych glikolu etylenowego w zmodyfikowanej reakcji Appela
    Direct synthesis of organic azides and thiols derived from ethylene glycol via modified Appel reaction 1
    Autorzy:
    Stefaniak, M.
    Jasiński, M.
    Urbaniak, K.
    Romański, J.
    Seliger, P.
    Gutowska, N
    Powiązania:
    https://bibliotekanauki.pl/articles/141899.pdf
    Data publikacji:
    2014
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Przemysłu Chemicznego. Zakład Wydawniczy CHEMPRESS-SITPChem
    Tematy:
    synteza organiczna
    tiole
    azydki
    reakcja „click”
    makrocykle
    kompleksy metali
    organic synthesis
    thiols
    azides
    click reaction
    macrocycles
    metal complexes
    Opis:
    Klasyczną metodę konwersji alkoholi pierwszorzędowych w odpowiednie halogenki alkilowe z użyciem trifenylofosfiny oraz tetrahalogenometanu, tzw. reakcję Appela, zaadoptowano do bezpośredniej syntezy terminalnych tioli i azydków organicznych pochodnych glikolu etylenowego oraz jego siarkowego analogu. W kluczowym etapie opisanej procedury one-pot, otrzymane in situ, w reakcji z N-bromosukcynimidem (NBS), odpowiednie dibromopochodne zostały przekształcone w związki docelowe w reakcji z nukleofilem siarkowym lub azotowym. Wybrane diazydki wykorzystano w syntezie nowych układów makrocyklicznych, które przetestowano pod kątem ich właściwości kompleksotwórczych.
    Classical method of conversion of primary alcohols into corresponding alkyl halides by usage of triphenylphosphine and tetrahalogenated methane, so-called Appel reaction, was adopted for the direct synthesis of terminal organic thiols and azides derived from ethylene glycol and its sulfurated analogue. In key step of the presented ‘one-pot’ protocol, corresponding dibromides, generated in situ via reaction with N-bromosuccinimide (NBS), were converted into desired products by treatment with appropriate sulfur or nitrogen nucleophile. A series of diazides and dithiols derived from (poly)ethylene glycols and their sulfur analogues were obtained. Selected diazides were utilized for the construction of novel macrocyclic systems, that were tested incontext of their complexing properties.
    Źródło:
    Chemik; 2014, 68, 7; 592-599
    0009-2886
    Pojawia się w:
    Chemik
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ditlenek węgla w syntezie organicznej
    Carbon dioxide in organic synthesis
    Autorzy:
    Burczyk, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/172758.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    wiązanie ditlenku węgla
    surowce odnawialne
    synteza organiczna
    kataliza
    kompleksy metali przejściowych
    carbon dioxide fixation
    renewable resources
    organic synthesis
    catalysis
    transition metal complexes
    Opis:
    Carbon dioxide is an abundant, cheap, almost nontoxic, thermodynamically stable, inert electrophile. Exploitation of CO 2 as a chemical feedstock, although will almost certainly not reduce its atmospheric concentration significantly, aims to generate high-value products and more-efficient processes. In recent years efficient transition-metal complexes have been used to perform homogeneously catalyzed transformations of CO 2 . This paper presents an overview of available catalytic routes for the synthesis of carboxylic acids, lactones, urea and carbamates, linear and cyclic carbonates as well as polycarbonates. Reduction processes of CO 2 are shortly men - tioned as well. C arboxylic acids have been synthesized via : (i) carboxylation of organolithium, organomagnesium (Scheme 2 [35]), organoboron (Scheme 3 [40 -42]), organozinc (Scheme 4 [43, 44]) and organotin (Scheme 5 [45, 46]) compounds; (ii) oxidative cycloaddition of CO 2 to olefins and alkynes (Scheme 6 -10 [47 -50, 57]) catalyzed by Ni(0)-complexes; (iii) transition-metal catalyzed reductive hydrocarboxylation of unsaturated compounds (Scheme 11, 12 [64 -67]); (iv) carboxylation of C-H bond (Scheme 13 [69 -71]). Telomerization of dienes, for instance 1,3-butadiene, and CO 2 in the presence of Ni(II) and Pd(II) complexes leads to lactones and esters of carboxylic acids (Scheme 14, 15 [73 -79]). Nucleophilic ammonia, primary and secondary amines react with CO 2 to give, respectively, urea and carbamic acid esters - carbamates and isocyanates (Scheme 16 -18 [94, 95]), thus eliminating the use of phosgene in their synthesis. CO 2 reacts with alcohols, diols and epoxides in the presence of transition-metal complexes (Fig. 2) and the reaction products are: linear carbonates (Scheme 20, 21 [110 -118]), cyclic carbonates (Scheme 22 -24 [153 -170]) and polycarbonates (Scheme 25, 26, Fig. 3, Tab. 1 [179 -186]). Finally, hydrogenation of CO 2 , leading to the formation of CO, HCOOH, CH 3 OH, CH 4 , C 2 H 6 and C 2 H 4 (Scheme 27), as well as electrochemical and photochemical reductions in the pre - sence of homogeneous and heterogeneous catalysts have been shortly reviewed.
    Źródło:
    Wiadomości Chemiczne; 2013, 67, 1-2; 1-53
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microwave synthesis of sulfanilic acid
    Synteza mikrofalowa kwasu sulfanilowego
    Autorzy:
    Havlíček, J.
    Myška, K.
    Tejchman, W.
    Karásková, N.
    Doležal, R.
    Maltsevskaya, N. V.
    Kolář, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/106593.pdf
    Data publikacji:
    2017
    Wydawca:
    Towarzystwo Chemii i Inżynierii Ekologicznej
    Tematy:
    synthesis of sulfanilic acid
    microwave assisted synthesis
    solvent-free synthesis
    school experiment
    organic chemistry education
    synteza kwasu sulfanilowego
    synteza mikrofalowa
    synteza bez rozpuszczalnika
    eksperyment szkolny
    edukacja chemii organicznej
    Opis:
    Sulfanilic acid represents an important substance, which is frequently utilized in the industry of azo dyes as well as in drug development of antimicrobials (e.g. of sulfonamides). Students can also meet with such type of compounds in chemistry labs, for example, when they estimate pH by methyl orange indicator or prepare Orange II for textile colouring. Both of these dyes are products of azo coupling of sulfanilic acid as diazonium salt with N,N-dimethylaniline or 2-naphthol, respectively. In the article, we focus on the synthesis of sulfanilic acid as a well-known experiment in the organic chemistry education. The synthesis was modified as the solvent free and microwave assisted experiment under semimicroscale conditions. That experiment is very convenient for the organic chemistry courses in the university or the high school teaching.
    Kwas sulfanilowy stanowi ważną substancję, często stosowaną w przemyśle barwników azowych, jak również w produkcji leków przeciwdrobnoustrojowych (np. sulfonamidów). Studenci mogą również spotykać się z takimi związkami w laboratoriach chemicznych, na przykład przy oznaczaniu pH z wykorzystaniem oranżu metylowego lub przy przygotowywaniu Oranżu II dla przemysłu tekstylnego. Oba te barwniki są produktami sprzężenia soli diazoniowych kwasu sulfanilowego odpowiednio z N,N-dimetyloaniliną lub 2-naftolem. W artykule przedstawiono syntezę kwasu sulfanilowego jako przykład dobrze znanego eksperymentu w edukacji chemii organicznej. Syntezę zmodyfikowano jako reakcję bez rozpuszczalników i wspomagano mikrofalowo w warunkach półmikropreparacji. Eksperyment ten powinien być przedstawiany podczas kursów chemii organicznej na uniwersytecie lub w szkole średniej.
    Źródło:
    Chemistry-Didactics-Ecology-Metrology; 2017, 22, 1-2; 93-98
    2084-4506
    Pojawia się w:
    Chemistry-Didactics-Ecology-Metrology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wspomagana mikrofalowo synteza 1,2,4-triazol-5-onu (TO)
    Microwave enhanced synthesis of 1,2,4-triazol-5-one (TO)
    Autorzy:
    Szala, M.
    Cudziło, S.
    Lewczuk, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/210885.pdf
    Data publikacji:
    2012
    Wydawca:
    Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
    Tematy:
    triazolon
    wspomagana mikrofalami synteza
    kondensacja kwasów z aminami
    triazolone
    microwave enhanced synthesis
    condensation of organic acids with amines
    Opis:
    Dokonano przeglądu literatury dotyczącej metod otrzymywania 1,2,4-triazol-5-onu od odkrycia tego związku w 1905 roku do 2010 r. Zaproponowano nową metodę syntezy TO polegającą na naświetlaniu mikrofalami mieszaniny kwasu metanowego (FA) i chlorowodorku semikarbazydu (SCH) przy stosunku molowym równym 2,0 i 2,5. Naświetlanie prowadzono wiązką mikrofal o mocy 800 W w czasie 6-40 minut. Mieszaninę poreakcyjną rozcieńczano wodą lub etanolem w celu odseparowania nieprzereagowanego kwasu mrówkowego. Uzyskaną zawiesinę ochładzano do 5°C, odsączano produkt i suszono w temperaturze 75°C. Zastosowanie mikrofal powoduje, że mieszanina reakcyjna ulega homogenizacji już po ok 10 minutach, co w tradycyjnym procesie wymaga (zależnie od skali) ok 30 minut. TO o najwyższej czystości uzyskano po 15 minutach reakcji przy stosunku molowym FA:SCH wynoszącym 2,5. Budowę produktu potwierdzono technikami analizy strukturalnej (¹H, ¹³C NMR) i jakościowej (FTIR).
    A new, simplified synthetic route for 1,2,4-triazol-5-one (TO) is reported. Microwave assisted condensation of semicarbazide hydrochloride with formic acid (1.0:2.0 and 1.0:2.5 mole ratio) is time and energy-efficient process. Triazolone synthesis by using classic heating requires 2 h to attain optimum yield. Microwave-enhanced condensation of semicarbazide hydrochloride with formic acid gave the desired product after 15 min with 63% yield. Structure of the final product was confirmed by the use of ¹H and ¹³C NMR and FTIR spectroscopy. Melting point determined by DTA technique for a sample obtained in microwave enhanced synthesis was identical like this parameter measured for sample from classical synthesis.
    Źródło:
    Biuletyn Wojskowej Akademii Technicznej; 2012, 61, 1; 299-308
    1234-5865
    Pojawia się w:
    Biuletyn Wojskowej Akademii Technicznej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Materiały MOF, nowa rodzina sit molekularnych o niezwykłych właściwościach i możliwościach zastosowań
    MOF materials, the new family of the molecular sieves with exceptional properties and possible applications
    Autorzy:
    Florczak, P.
    Janiszewska, E.
    Kędzierska, K.
    Kowalak, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/171820.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    organiczno-nieorganiczne sita molekularne
    związki metaloorganiczne MOF
    synteza
    zastosowanie
    właściwości
    organic-inorganic molecular sieves
    MOF
    structure
    synthesis
    properties
    applications
    Opis:
    The metal organic frameworks (MOFs) are a novel group of molecular sieves discovered in the last decade of the twentieth century. Most of conventional molecular sieves such as microporous zeolites and zeolite-like materials, ordered mesoporous materials (M41S) are typical inorganic compounds. Although their synthesis often involves an assistance of organic compounds acting as structure directing agents and organic solvents are sometimes applied during their crystallization, the organics are always removed from resulted products (mainly by calcinations). The MOFs are crystalline materials build of metal ions or ion clusters coordinatively bonded with organic segments (linkers) that form porous (one-, two-, or threedimensional) structures. The various coordination number of selected metal and the nature of organic linkers allow to prepare a great variety of structures with different properties. The inorganic components comprise a great variety of transition (e.g. Zn Cu, Fe, rare earths) and base metal (e.g. Al) cations of different valence. The organic linkers are functionalized compounds containing O, N, P, S atoms (i.e. carboxylates, phosphonates, sulfonates, cyanides, amines, imidazoles) enable to chelate the inorganic cations. The organic subunits can be additionally modified by substitution of other functional groups (halogens, hydroxyls, aminogroups). The MOF materials are mostly prepared similarly as zeolitic materials by crystallization in solvothermal conditions. The solvents (water or organic compounds) can play a role of templates, although sometimes additional structure directing agents are admitted into the initial mixtures. The crystallization is always conducted in moderate temperatures (20–200°C). After removal of solvents well ordered pore systems are available for selective adsorption and for other applications. The thermal stability of this family of molecular sieves is obviously lower than that of inorganic materials, but most of them can withstand heating at 350–400°C, which still makes them suitable for variety of potential applications. The adsorption properties of MOFs makes them very appealing for practical application. The recorded surface areas of some types are overwhelming and they surpass 5000 m2/g. The high adsorption capacity is very promising for storage of fuels (natural gas, hydrogen) or waste gases (CO2, SO2) as well as for their separation. The great and very fast growing variety of structures and chemical compositions brings also a hope to use them as efficient catalysts. The metal segments, functional groups in organic blocks as well as occluded or encapsulated species can play a role of catalytically active sites. The MOF materials can be also applied as matrices for sensors, pigments, and microelectronic or optical devices.
    Źródło:
    Wiadomości Chemiczne; 2011, 65, 5-6; 427-460
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synteza policyklicznych, skondensowanych węglowodorów heteroaromatycznych zawierających w pierścieniu atomy azotu i siarki
    Synthesis of polycyclic, linearly fused heteroaromatic hydrocarbons containing nitrogen and sulfur atoms
    Autorzy:
    Bodzioch, A.
    Bałczewski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/410271.pdf
    Data publikacji:
    2010
    Wydawca:
    Uniwersytet Humanistyczno-Przyrodniczy im. Jana Długosza w Częstochowie. Wydawnictwo Uczelniane
    Tematy:
    organiczna elektronika
    liniowo skondensowane, policykliczne węglowodory heteroaromatyczne
    związki czynne biologicznie
    synteza
    organic electronics
    linearly fused, policyclic heteroaromatic hydrocarbons
    biologically active compounds
    synthesis
    Opis:
    W przeglądzie zaprezentowano metody syntezy policyklicznych, liniowo skondensowanych węglowodorów heteroaromatycznych zawierających w pierścieniu aromatycznym atomy siarki i azotu. W ostatnich latach związki te znalazły praktyczne zastosowanie w syntezie produktów czynnych biologicznie oraz w badaniach nad najnowszej generacji organicznymi elementami elektronicznymi, takimi jak diody, tranzystory, ogniwa, lasery, bramki logiczne, koncentratory słoneczne, itp.
    In this review, methods of syntheses of polycyclic, linearly fused heteroaromatic hydrocarbons containing nitrogen and sulfur atoms are presented. These compounds have recently found applications in synthesis of biologically active compounds and in research on the newest generation of organoelectronic devices, like diodes, transistors, photovoltaics, lasers, logic gates, solar concentrators, etc.
    Źródło:
    Chemistry, Environment, Biotechnology; 2010, 14; 7-33
    2083-7097
    Pojawia się w:
    Chemistry, Environment, Biotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Otrzymywanie i właściwości adsorpcyjne sieci metaloorganicznych
    Synthesis and adsorption properties of metal-organic frameworks
    Autorzy:
    Szeligowska, S.
    Choma, J.
    Jaroniec, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/171540.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    sieci metaloorganicze
    MOF
    synteza materiałów MOF
    adsorpcja
    CO2
    adsorpcja H2
    metal-organic frameworks
    synthesis of MOF materials
    adsorption
    H2 adsorption
    Opis:
    MOF materials or metal-organic frameworks are compounds consisting of metal ions or clusters (metal junctions) and organic ligands (bridging groups) connected via coordination bonds. Since a variety of organic ligands and metal junctions is available, metal-organic frameworks of desired composition and structures can be synthesized. These compounds are relatively new, intensively studied, their number is continuously growing from year to year. Metalorganic frameworks may also possess elastic properties due to the presence of coordination bonds in their structure. A distinct feature of MOF materials, which differentiates them from other sorbents, is the possibility of changing their pore structure under influence of external stimuli and the ability of adjusting their pore size to the dimensions of the adsorbed molecules. An interesting phenomenon observed in these materials is the so-called “breathing” effect that is manifested by drastic changes in the pore volume upon external stimuli such as temperature, pressure, type of adsorbate, presence of solvent. There are numerous methods for the preparation of MOF materials: solvothermal, electrochemical, mechanochemical, sonochemical and microwave-assisted syntheses. An additional activation of these materials is often required to remove the remaining solvents from pores and consequently, increase their adsorption capacity. The latter can be also increased by additional modifications that can be used to tune their physicochemical properties, and especially porosity. Due to the excellent adsorption properties of MOF, especially very high BET specific surface area (up to 6200 m2/g) and large pore volume, these materials have been intensively studied for capture or storage of various gases such as CO2, H2 and CH4. Applications of metal-organic frameworks are continuously growing and range from gas storage, chemical sensors and phosphors to medicine, where they are used as drug carriers.
    Źródło:
    Wiadomości Chemiczne; 2017, 71, 5-6; 299-322
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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