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Polycyclotrimerization of alkynes with internal ethynyl groups
Sokol, Jiří ; Sedláček, Jan (advisor) ; Balcar, Hynek (referee)
The diynes of both aliphatic and aromatic types comprising either (i) two internal ethynyl groups or (ii) one internal and one terminal ethynyl group in the molecule were revealed as appropriate monomers for the Co2(CO)8 catalyzed polycyclotrimerization yielding high-molecular-weight products. The polycyclotrimerization of aliphatic diynes with a short (CH2)2 link between ethynyl groups and the polycyclotrimerization of aromatic diynes provided polycyclotrimer networks with tri-, tetra-, penta- and hexasubstituted benzene segments. The polycyclotrimers of aliphatic diynes did not exhibit microporous texture. On the other side, the polycyclotrimers of aromatic monomers were mostly microporous with specific surface area up to SBET = 499 m2 /g. The nitrogen desorption isotherms on microporous polycyclotrimers exhibited a significant unclosed hysteresis. This indicated that the penetration of nitrogen into polymers was accompanied by formation of temporary pores or opening permanent pores of worse accessibility.
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Preparation and properties of building blocks of specialty polymers
Šichová, Kristýna ; Svoboda, Jan (advisor) ; Sedláček, Jan (referee)
This Diploma Thesis presents results obtained by solution of two partial projects: a) Preparation of monomers from renewable sources using metathesis and tandem hydrogenation catalyzed with ruthenium compounds - project solved during my Erasmus stay at the Université de Rennes 1 in France; b) Preparation and properties of ,-bis(tpy)quarterthiophene oligomers carrying ionic side groups as oligomonomers for polyelectrolyte conjugated dynamers - project solved at the Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague. Project a): Self-metathesis of 1,2-epoxyhex-5-ene (but-3-enyloxirane) and its cross-metathesis with methyl acrylate and acrylonitrile catalyzed with ruthenium compounds as well as tandem design of these metatheses and consecutive hydrogenation of their products by gaseous hydrogen have been optimized. The following influences have been studied and tuned: (i) type of the catalyst (Grubbs, Hoveyda, Zhan) and its concentration and method of dosing, (ii) concentration of reactants and additives, (iii) type of solvent, and (iv) reaction temperature. Reactions were monitored by the GC, GC and MS methods and the products were characterized by the NMR method. Methyl 6,7-epoxyheptanoate (methyl 5-oxiranylpentanoate) obtained by the tandem...
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Study of adsorption efficiency of diosmectite and charcoal on selected model compounds causing acute intoxication in the Czech Republic
Mináriková, Michaela ; Martínková, Markéta (advisor) ; Sedláček, Jan (referee)
The first step in treatment of acute intoxications is usually based on a method suitable to eliminate the toxic agent from the poisoned body. The principle of such a method consists of binding the harmful substances to the surface of a suitable adsorbent material. The aim of the present study was to compare the adsorption ability of two adsorbent materials, namely diosmectite and activated charcoal towards selected model compounds which are most commonly involved in acute intoxication in the Czech Republic. The eleven model compounds were selected: acetylsalicylic acid, α-amanitin, amlodipine, digoxin, phenobarbital, ibuprofen, imipramine, carbamazepine, oxazepam, promethazine, and theophylline. Of the tested compounds, promethazine was most effectively adsorbed to diosmectite. Its adsorption to diosmectite (0.191 ± 0.035 mg promethazine/mg diosmectite) was significantly higher than its adsorption to activated charcoal. Amlodipine, imipramine and carbamazepine were adsorbed both to diosmectite and to charcoal, by analogous efficiencies. The effect of temperature and pH on the adsorption efficiencies of these adsorbents was also evaluated. The utilized pH simulated physiological conditions in the various parts of the gastrointestinal tract. Surprisingly, the pH was not found to significantly...
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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...
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Palladium catalysts deposited over novel siliceous supports
Křečková, Pavlína ; Štěpnička, Petr (advisor) ; Sedláček, Jan (referee)
Title: Palladium catalysts deposited over novel siliceous supports Author: Pavlína Křečková Department: Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague Supervisor: prof. RNDr. Petr Štěpnička, Ph.D. Supervisor's e-mail address: stepnic@natur.cuni.cz Advisor: prof. Ing. Jiří Čejka, DrSc. Advisor's e-mail address: jiri.cejka@jh-inst.cas.cz Abstract Keywords: palladium; deposited catalysts; siliceous supports; C-C coupling reaction. The aim of this work was to prepare a deposited palladium catalyst from Pd2+ and twodimensional zeolite ITQ-2 bearing ≡SiCH2CH2CH2NHCH2CH2NEt2 groups at the surface. This catalys has been evaluated in the Heck reaction between n-butyl-acrylate and brombenzene to give n-butyl-cinnamate. Influence of the reaction temperature, the solvent, base and hydrate water on the progress of the Heck reaction was investigated. This work also deals with the possibility of recycling the catalyst and, due to its nature, with the quantity of leached palladium into the reaction mixture. Furthermore, the work describes differences in morphology between the fresh and a recycled catalyst.
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Přirozená retence vody v krajině versus výstavba retenčních nádrží
SEDLÁČEK, Jan
This work is focused on natural water retention in landscape. There are described basic principles of water behaviour in soil, comparing of water retention in different types of land-use and anthropogenic influences including flood-protection and land-use changes. In the practicle part, there is described an experiment which focuses on comparing of retention potential of land-use changes in catchment of water dam Orlík with retention capacity of the dam. This work includes GIS analysis which focuses on areas of each type of land-use in the Orlík catchment.
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To Dvur Kralove by train - Transfer Terminal in Dvur Kralove nad Labem
Černá, Tereza ; Sedláček, Jan (referee) ; Ponešová, Barbora (advisor)
During the design process, I used the approaches of individual transport and pedestrian facilities to the plot. When analyzing pedestrian access, it became clear that the parcel can be taken from almost all directions, so the orientation of the terminal is not clearly predetermined. In connection with a diverse surrounding area that at present does not offer any attractive surrounding scene, I decided to turn the orientation towards the center to create a yard that will link individual transport sites, allow access from all corners of the parcel, and create a central area for visitors of terminal.
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To Dvur Kralove by train - Transfer Terminal in Dvur Kralove nad Labem
Vinklárková, Eliška ; Sedláček, Jan (referee) ; Foretník, Jan (advisor)
The main objective of the proposal was not to create a barrier for the inhabitants or tourists by integrating transport on this parcel, leaving it as far as possible to the pedestrians. Movement of pedestrians and vehicles should not cross. The new tracks are therefore moved to the existing siding. Bus traffic should take place at busy local roads. The terminal building is in the center of the plot and is a link between bus, train, car and pedestrians. Thanks to the selected transport solution, the parcel is free from the traffic barriers and there is a free pedestrian spread. At the same time, the transport solution does not allow the free passage of the population to the south. The location of the scatter surface naturally guides the visitor and the inhabitants of the city to their area of interest - a departure from the industrial part of the city.
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Deposited palladium catalysts for C-C bond forming reactions
Semler, Miloslav ; Štěpnička, Petr (advisor) ; Sedláček, Jan (referee)
Palladium based catalysts are widely used for C-C bonding reactions. This work describes the preparation of several such catalysts deposited onto siliceous, SBA-15 type support and common silica gel, whose surface was modified by organic chains with amine donor groups. The prepared catalysts have been tested in coupling reactions of organotin compounds and organic halides (Stille reactions) under various conditions.
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