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Special Laboratory Techniques
Boháčová, Zdeňka ; Merna,, Jan (referee) ; Richtera, Lukáš (advisor)
Manipulation with the materials that are very sensitive towards moisture and (or) oxygen requires controlled environment with acceptable content of these undesired species in the range of ppm units. The knowledge of vacuum techniques, techniques of the dry box and Schlenk techniques is necessary in the area of inorganic, organic, and especially organometallic and polymer syntheses. General procedures that are related to these techniques are described in many lecture notes and monographs, but the graphic form which can enhance correct understanding, is often very poor. The thesis is divided into eight chapters, beginning with laboratory safety, risk assessment and the first aid. Following chapter brings useful literature sources. Used glassware, laboratory equipment and accessories and special techniques are described in other chapters. The aim of this work was to create the study materials which could be utilized by the workers dealing with the syntheses of organometallic complexes, catalytic precursors for polymerization and polymerization in itself in the laboratory of polymer synthesis at the Faculty of Chemistry, BUT.
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Determination of propene polymerization kinetics on Ziegler-Natta catalysts by methods of batch and Stopped-Flow polymerization performed under industrial conditions
Tvrdý, Michal ; Merna,, Jan (referee) ; Kratochvíla, Jan (advisor)
This thesis is focused on the determination of the propene polymerization kinetics on phthalate and nonphthalate diester Ziegler-Natta MgCl2-supported catalysts under the industrial conditions. The kinetic profiles were determined by various laboratory techniques for propene polymerization. For assessing the profiles were utilized batch gas and liquid polymerization modes in 2-litre and 4-litre reactors. Finally, the results were complemented with the runs performed in a unique Stopped-Flow apparatus, which allows polymerization of liquid propene at very short polymerization times. The kinetics profiles of both catalysts were determined and compared by combination of experimental data of these techniques. The basic properties of the synthesized polymeric powders were measured, such as the melt flow index, bulk density and amount of polypropene fraction soluble in cold xylene.
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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...
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Homogeneous and heterogeneous titanium complexes and their use for selective ethylene trimerization to 1-hexene
Hodík, Tomáš ; Pinkas, Jiří (advisor) ; Merna, Jan (referee)
This diploma thesis is focused on the design and synthesis of new half-sandwich titanium complexes for anchoring to selected supports (SiO2, SBA-15) and the study of their catalytic activity and selectivity in ethylene trimerization to 1-hexene. The synthetic strategy of half-sandwich titanium complexes with a suitable leaving group for direct anchoring through Ti−O bond was carried out (Cl, Oi-Pr). In addition, the titanium complexes with pendant alkenyl group were prepared and utilised for anchoring to a SiMe2H modified support by Pt-catalysed hydrosilylation reaction. Prepared compounds were characterised by standard spectroscopic methods (IR, NMR, MS). The heterogeneous systems were characterised by MAS NMR and IR spectroscopy, powder XRD, ICP-OES, TGA and the textural parameters were determined from nitrogen adsorption/desorption isotherms. For all prepared materials was studied the catalytic activity for ethylene trimerization and the selectivity to 1-hexene.
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Determination of propene polymerization kinetics on Ziegler-Natta catalysts by methods of batch and Stopped-Flow polymerization performed under industrial conditions
Tvrdý, Michal ; Merna,, Jan (referee) ; Kratochvíla, Jan (advisor)
This thesis is focused on the determination of the propene polymerization kinetics on phthalate and nonphthalate diester Ziegler-Natta MgCl2-supported catalysts under the industrial conditions. The kinetic profiles were determined by various laboratory techniques for propene polymerization. For assessing the profiles were utilized batch gas and liquid polymerization modes in 2-litre and 4-litre reactors. Finally, the results were complemented with the runs performed in a unique Stopped-Flow apparatus, which allows polymerization of liquid propene at very short polymerization times. The kinetics profiles of both catalysts were determined and compared by combination of experimental data of these techniques. The basic properties of the synthesized polymeric powders were measured, such as the melt flow index, bulk density and amount of polypropene fraction soluble in cold xylene.
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Homogeneous and heterogeneous titanium complexes and their use for selective ethylene trimerization to 1-hexene
Hodík, Tomáš ; Pinkas, Jiří (advisor) ; Merna, Jan (referee)
This diploma thesis is focused on the design and synthesis of new half-sandwich titanium complexes for anchoring to selected supports (SiO2, SBA-15) and the study of their catalytic activity and selectivity in ethylene trimerization to 1-hexene. The synthetic strategy of half-sandwich titanium complexes with a suitable leaving group for direct anchoring through Ti−O bond was carried out (Cl, Oi-Pr). In addition, the titanium complexes with pendant alkenyl group were prepared and utilised for anchoring to a SiMe2H modified support by Pt-catalysed hydrosilylation reaction. Prepared compounds were characterised by standard spectroscopic methods (IR, NMR, MS). The heterogeneous systems were characterised by MAS NMR and IR spectroscopy, powder XRD, ICP-OES, TGA and the textural parameters were determined from nitrogen adsorption/desorption isotherms. For all prepared materials was studied the catalytic activity for ethylene trimerization and the selectivity to 1-hexene.
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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...
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Special Laboratory Techniques
Boháčová, Zdeňka ; Merna,, Jan (referee) ; Richtera, Lukáš (advisor)
Manipulation with the materials that are very sensitive towards moisture and (or) oxygen requires controlled environment with acceptable content of these undesired species in the range of ppm units. The knowledge of vacuum techniques, techniques of the dry box and Schlenk techniques is necessary in the area of inorganic, organic, and especially organometallic and polymer syntheses. General procedures that are related to these techniques are described in many lecture notes and monographs, but the graphic form which can enhance correct understanding, is often very poor. The thesis is divided into eight chapters, beginning with laboratory safety, risk assessment and the first aid. Following chapter brings useful literature sources. Used glassware, laboratory equipment and accessories and special techniques are described in other chapters. The aim of this work was to create the study materials which could be utilized by the workers dealing with the syntheses of organometallic complexes, catalytic precursors for polymerization and polymerization in itself in the laboratory of polymer synthesis at the Faculty of Chemistry, BUT.
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LC-NMR Analysis of Phenylsilane Polymers
Pinkas, Jiří ; Merna, J. ; Sýkora, Jan
We report the analysis of dehydrocoupling polymerization reactions of phenylsilane via on-flow LC-NMR experiment. The successful separation was achieved by isocratic elution of acetonitrile and aceton (80:20). The separation was solely monitored by 1H NMR detection. The properties of the polymeric product depend on the catalytical system. The products can differ in the molar weight distribution, degree of branching and amount of cyclic and rearranged products. In our particular cases, the weight average molar mass (Mw) varies from several silane units up to 4100 g.mol-1. The branching of polysilanes is monitored by 29Si{1H} INEPT experiment with the polarization transfer from the ortho hydrogen (J~7 Hz). The connectivity within branched unit was established via 1H à 29Si-29Si INEPT-INADEQUATE experiment.
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