|
|
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...
|
|
|
Templating as a new method of creating and modifying the porous texture of polyacetylene networks
Sokol, Jiří ; Sedláček, Jan (advisor) ; Balcar, Hynek (referee)
A new method of introducing permanent micropores into hyper-cross-linked polyacetylene networks has been developed. The method used a combination of polyacetylene chemistry and Schiff base chemistry. Through the coordination chain-growth polymerization of monomers with polymerizable ethynyl groups, a wide series of homopolymer and copolymer networks with rigid polyene main chains interconnected by arylene links was prepared. The networks carried substituents of the predominantly aromatic Schiff-base-type in the pendant groups. With increasing content and volume of these substituents the specific surface area of the networks decreased. The networks with a high content of Schiff-base-type substituents were non-porous. The prepared networks were subsequently hydrolyzed under the conditions optimized in this diploma thesis. The hydrolysis led to a highly efficient cleavage of the Schiff base methanimine linkages and to the removal of the cleaved low molecular weight aromatic amine and aldehyde segments from the networks. In this way, new functional groups were generated in the networks, either CH=O or NH2. The hydrolytic modification had a fundamental effect on the texture parameters of the networks. The modification of the originally microporous networks mostly led to an increase in the specific...
|
|
|
Conjugated porous polymers derived from diethynylarenes by chain-growth polymerization and polycyclotrimerization
Slováková, Eva ; Sedláček, Jan (advisor) ; Merna, Jan (referee) ; Červený, Libor (referee)
4 ABSTRACT The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated...
|
|
|
Functionalized microporous polymer networks prepared from ethynylarenes
Stahlová, Sabina ; Sedláček, Jan (advisor) ; Etrych, Tomáš (referee) ; Červený, Libor (referee)
The preparation of a new group of functionalized conjugated polymer networks has been described based on spontaneous quaternization polymerization of ethynylpyridines with bis(bromomethyl)arenes. The networks consisted of polyacetylene chains with pyridyl and pyridiniumyl pendants cross-linked with -CH2(arylene)CH2- links. The variation of the ratio of monomer and quaternization agent in the feed modified the ratio of pyridyl and pyridiniumyl groups in the networks (pyridyl/pyridiniumyl ratios from 0 to 1.32). The networks did not exhibit a permanent microporosity that could be confirmed by nitrogen adsorption at 77 K. Nevertheless, all networks were active in capture of CO2 at 293 K (up to 0.73 mmol CO2/g, 750 Torr). It has been hypothesized that CO2 capture reflected formation of a temporary porous texture of the networks through conformational changes of the network segments enabled by the segments mobility at room temperature. The preparation of functionalized conjugated polymer networks with permanent micro/mesoporosity (SBET up to 667 m2 /g) has been described that was based on chain coordination copolymerization of acetylenic monomers. The copolymerization of 1,4-diethynylbenzene or 4,4'-diethynylbiphenyl with mono or diethynylbenzenes bearing NO2 or CH2OH groups has been demonstrated as...
|
|
|
Preparation of functionalized polyacetylenes with linear and cross-linked architecture
Havelková, Lucie ; Sedláček, Jan (advisor) ; Balcar, Hynek (referee)
The phenylacetylene type monomers with benzene ring substituted with one or two aldehyde groups (besides an ethynyl group) were efficiently polymerized into linear mostly high-molecular-weight polyacetylenes with aldehyde groups in pendants if the complex [Rh(NBD)acac] was used as the polymerization catalyst. To achieve high yield and molecular weight of the polymer the positioning of the aldehyde group to meta position with respect to the ethynyl group was most appropriate. It was confirmed that polyacetylenes with aldehyde groups were modifiable by a reaction with p-toluidine under formation of Schiff base type pendant groups. 1,3-Diethynylbenzenes with various substituents in position 5 on the ring (R = H, F, Cl, Br, HCO, NO2, COOCH3) were efficiently polymerized with [Rh(NBD)acac] catalyst into microporous or micro/mesoporous polyacetylene networks that exhibited specific surface area from 311 to 1146 m2 /g. In the case of the networks with HC=O groups, the positive effect of these groups was confirmed on the capacity of the network in CO2 and methanol vapor capture. The composition and texture of the networks possessing HC=O groups were partly reversibly modifiable in reaction with p-toluidine.
|
|
|
Characterization of poly(1,4-diethynylbenzene) by IGC method
Petrášová, Sabina ; Sedláček, Jan (advisor) ; Pacáková, Věra (referee)
Poly(1,4-diethynylbenzene) ( -conjugated polymer) was prepared as an insoluble polymer network via chain coordination polymerization of 1,4-diethynylbezene catalyzed with [Rh(NBD)acac] complex. Thermodynamic properties and acid-base characteristics of the prepared poly(1,4-diethynylbenzene) were studied by means of Inverse Gas Chromatography (IGC) in the temperature range 80-100 řC. Retention data of selected testing substances were used to determine the Gibbs energy of sorption, the sorption enthalpy and their acid-base and disperse parts as well as the disperse contribution to the surface energy and parameters of KA, KD, ANHPS and DNHPS quantifying the acid-base character of the studied polymer. The results showed that poly(1,4-diethynylbenzene) interacted more efficiently with Lewis bases than with Lewis acids. The values of experimental sorption enthalpy were used for the determination of the parameters KA and KD. Values of these parameters classify poly(1,4-diethynylbenzene) as the material with a slightly acid character. This conclusion is further supported by the results of H. P. Schreiber method based on the application of ANHPS and DNHPS parameters for the evaluation of the acid-base properties of the material. The infrared spectroscopy proved that poly(1,4-diethynylbenzene) contained...
|
|
|
Study of molecular weight and configurational stability of substituted polyacetylenes
Trhlíková, Olga ; Sedláček, Jan (advisor) ; Netopilík, Miloš (referee) ; Žigon, Majda (referee)
3 ABSTRACT Complexes [Rh(cycloolefin)(acac)] (cycloolefin = norborna-2,5-diene, cycloocta- 1,5-diene and cyclooctatetraene) were investigated as catalysts of polymerization of monosubstituted acetylenes into stereoregular cis-transoid polyacetylenes. All complexes were highly active in arylacetylenes polymerizations in both coordinating and non-coordinating solvents. Selection of solvent and cycloolefin ligand of the catalyst allowed the control over polymer MW. The onset of initiation in the [Rh(cycloolefin)(acac)]/monomer systems proceeded as the proton transfer from the monomer molecule to the acac ligand under the release of acetylacetone and coordination of -C≡CR ligand to Rh(cycloolefin) moiety. Cis-transoid poly(phenylacetylene) and poly[(2,4-difluorophenyl)acetylene]s with required initial MW were prepared with these catalysts and submitted to the long-term ageing in which the polymers were exposed to the atmosphere and diffuse daylight either dissolved in tetrahydrofuran or in the solid state. Tightly connected processes of cis-to-trans isomerization of the polymer main-chains double bonds and oxidative degradation were found to proceed during polymers ageing in the solution. Besides, the formation of corresponding cyclotrimers accompanied the polymers ageing. However, the cyclotrimers amount was...
|
|
|
Conjugated porous polymers derived from diethynylarenes by chain-growth polymerization and polycyclotrimerization
Slováková, Eva
The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated that...
|
|
|
Functionalized microporous polymer networks prepared from ethynylarenes
Stahlová, Sabina
The preparation of a new group of functionalized conjugated polymer networks has been described based on spontaneous quaternization polymerization of ethynylpyridines with bis(bromomethyl)arenes. The networks consisted of polyacetylene chains with pyridyl and pyridiniumyl pendants cross-linked with -CH2(arylene)CH2- links. The variation of the ratio of monomer and quaternization agent in the feed modified the ratio of pyridyl and pyridiniumyl groups in the networks (pyridyl/pyridiniumyl ratios from 0 to 1.32). The networks did not exhibit a permanent microporosity that could be confirmed by nitrogen adsorption at 77 K. Nevertheless, all networks were active in capture of CO2 at 293 K (up to 0.73 mmol CO2/g, 750 Torr). It has been hypothesized that CO2 capture reflected formation of a temporary porous texture of the networks through conformational changes of the network segments enabled by the segments mobility at room temperature. The preparation of functionalized conjugated polymer networks with permanent micro/mesoporosity (SBET up to 667 m2 /g) has been described that was based on chain coordination copolymerization of acetylenic monomers. The copolymerization of 1,4-diethynylbenzene or 4,4'-diethynylbiphenyl with mono or diethynylbenzenes bearing NO2 or CH2OH groups has been demonstrated as...
|
guest ::
