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Tytuł:
Błękit Majów , jedno z najważniejszych osiągnięć Mezoameryki
Maya Blue , one of the most important achievements of Mesoamerica
Autorzy:
Łukarska, M.
Zywert, A.
Kowalak, S.
Powiązania:
https://bibliotekanauki.pl/articles/172584.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
Błękit Majów
zeolity
pigmenty
enkapsulacja
indygo
Maya Blue
pigments
zeolites
indigo
encapsualtion
Opis:
The Maya Blue is a famous blue pigment developed by pre-Columbian civilizations of Mesoamerica and manufactured there for about thousand years. It was applied for body decoration, important for cruel religious rituals, as well as for artistic paintings, murals, or coloration of ceramics. Its production was abandoned in XVII century and the procedure forgotten. The chemical nature of this blue pigment remained a puzzle for a long time and only in nineteen sixties it was revealed [1, 2] that it is a composite consisting of inorganic matrix (palygorskite) that accommodates molecules of organic dye – indigo. The preparation procedure was rediscovered [3] and the products analogous to classical Maya Blue could be obtained by simple thermal insertion of indigo into palygorskite (and also into sepiolite). However, the nature of chemical interaction between dye and matrix that provides very high resistibility of resulting pigments remains still not satisfactorily explained. The hydrogen bonds or coordinative interaction with matrix cations are taken into an account. Zeolites and other molecular sieves can be efficiently applied as matrices for pigments similar to Maya Blue. The coloration and other properties of pigments can be considerably changed by initial modification of zeolites with various cations, what supports an important role of complexes formed by dye molecules and zeolite cations. On the other hand, the zeolite-like materials AlPO4 as well as to some extent mesoporous silica (with some contribution of micropores) lacking any cations are also efficient matrices for pigments analogous to Maya Blue. Not only indigo, but also indigo derivatives (leucoindigo, thioindigo, indigo carmine) could be embedded inside the molecular sieves. The thermal insertion as well as crystallization of zeolites from gels supplemented with respective dye can be used for pigment synthesis. It is interesting that role of matrix can be also played by representative of novel MOF family of the molecular sieves.
Źródło:
Wiadomości Chemiczne; 2012, 66, 7-8; 715-739
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
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
    Wyświetlanie 1-2 z 2

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