|
|
Functionalized hyper-cross-linked porous polyacetylenes
Havelková, Lucie
An atom-economic one-step chain-growth coordination homopolymerization providing high yields of functionalized hyper-cross-linked polyacetylenes with permanent micro/mesoporous texture and specific surface area up to 1062 m2 /g was introduced and optimized. Substituted 1,3-diethynylbenzenes served as monomers simultaneously providing functionalization and hyper-cross-linking of the networks. The homopolymerization was compatible with the heteroatom groups of the monomers and allowed to prepare polyacetylene networks with the wide spectrum of univalent functional groups: -F, -Cl, -Br, -NO2, -COOCH3, -CH2OH, -COOH and -CH=O decorating the aromatic segments of the networks in a high extent (7.87 mmol/g). A novel two-step synthesis of functionalized hyper-cross-linked polyacetylenes was introduced combining chain-growth coordination polymerization of acetylenic monomers and covalent templating using acetal and Schiff base protecting groups. By postpolymerization hydrolytic removal of the protecting segments from the primary networks, the networks with a high content (up to 9.61 mmol/g) of univalent functional groups -CH2OH, -CH=O and -NH2 were prepared. These groups were placed either on the cross-linking or linear (aromatic and aliphatic) network segments, even in the vicinity of the main...
|
|
|
Functionalized hyper-cross-linked porous polyacetylenes
Havelková, Lucie ; Sedláček, Jan (advisor) ; Brožek, Jiří (referee) ; Balcar, Hynek (referee)
An atom-economic one-step chain-growth coordination homopolymerization providing high yields of functionalized hyper-cross-linked polyacetylenes with permanent micro/mesoporous texture and specific surface area up to 1062 m2 /g was introduced and optimized. Substituted 1,3-diethynylbenzenes served as monomers simultaneously providing functionalization and hyper-cross-linking of the networks. The homopolymerization was compatible with the heteroatom groups of the monomers and allowed to prepare polyacetylene networks with the wide spectrum of univalent functional groups: -F, -Cl, -Br, -NO2, -COOCH3, -CH2OH, -COOH and -CH=O decorating the aromatic segments of the networks in a high extent (7.87 mmol/g). A novel two-step synthesis of functionalized hyper-cross-linked polyacetylenes was introduced combining chain-growth coordination polymerization of acetylenic monomers and covalent templating using acetal and Schiff base protecting groups. By postpolymerization hydrolytic removal of the protecting segments from the primary networks, the networks with a high content (up to 9.61 mmol/g) of univalent functional groups -CH2OH, -CH=O and -NH2 were prepared. These groups were placed either on the cross-linking or linear (aromatic and aliphatic) network segments, even in the vicinity of the main...
|
|
|
Three-dimensionally ordered micromesoporous carbon as adsorbent for CO2 capture
Vorokhta, Maryna ; Řimnáčová, Daniela ; Pilař, Radim
In this work, ordered three-dimensionally micromesoporous carbon composed of large spherical mesopores 13 nm in diameter and small micropores with a mean micropore width of 1.46 nm, connecting the main spheres, was synthesized and investigated for CO2 capture ability at temperatures of 25°C, 35°C and 50°C, and at pressures up to 6.5 MPa. Because of the big pore volume occupying 3.62 cm3/g, composed of mesopores and micropores, the carbon sample showed very high adsorption capacity at high pressures. The highest CO2 adsorption capacity of 24.03 mmol/g was obtained at 25°C and at 5.5 MPa. As the temperature increased, the CO2 adsorption capacity decreased to 13.34 mmol/g at 50°C and at 6.5 MPa. The Freundlich fittings of the measured adsorption isotherms at pressures up to 2 MPa showed very high correlation coefficients. The estimated isosteric heats of adsorption in the range of 5.62-6.90 kJ/mol indicated a physical adsorption process, and suggested a stronger interaction between CO2 molecules than between CO2 molecules and the surface of the carbon sample.
|
|
|
Adsorption study of waste materials as potential adsorbents for pollutant removal and storage
Řimnáčová, Daniela ; Vorokhta, Maryna ; Vöröš, Dominik ; Borecká, Lenka ; Bičáková, Olga
The study shows how changing the experimental conditions during carbonization of a waste material such as sewage sludge influences textural properties and the CO2adsorption capacity of final carbonized productsin their potential use for removaland storage of pollutantssuch as carbon dioxide. The CO2adsorption measurements were done with gravimetric and manometric sorption devices in a wide range of pressures and temperatures. Further, CO2adsorption capacities of other materialssuch as activated carbon prepared from black carbon and a Czech Silurian shalewere compared toadsorption capacities of the studied carbonized sewage sludge. These two compared materials were chosen according to their compositionsand porosity.The porosityof the studied materials was determined from the N2sorption isotherms and measurements of their skeletal density with He.The adsorption capacity depended on the ratio of micropores and mesopores in the carbonized sewage sludge, because CO2fillsmicropores and mesopores at lowand highpressures, respectively, and was decreasing with the temperature increase atconstant pressure.The adsorption capacity of the carbonized sewage sludgewas increased by increase inthe carbonization temperature.The obtained adsorption capacities showed that the carbonization of sewage sludge can lead to preparation of perspective adsorbents for CO2capture and storage.
|
guest ::
