|
| |
|
|
Chemistry of polynitro heterocyclic compounds
Kubátková, Nela ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
The review of polynitro heterocyclic compounds was written. These are substances with ability to detonate, which is caused mainly by presence of nitrogroups, which are bonded to carbon atoms in their cycles. The thesis deals with common polynitro five-membered heterocycles with one nitro atom, up to six-membered heterocycles with three nitrogen atoms. There are processed basic information of these compounds, as well as their physical-chemical properties and properties of detonation, the possibility of their preparation, which are displayed in the form of chemical reactions.
|
|
|
The Usage of Separation Methods for Research of Biologically Active Substances in Waters
Vydrová, Lucie ; Friedl, Zdeněk (referee) ; Opatřilová, Radka (referee) ; Chýlková,, Jaromíra (referee) ; Vávrová, Milada (advisor)
Pharmaceuticals are biological active compounds with different functional groups, physico-chemical and biological properties. These chemical compounds are called as “new contaminants” which cumulate in various environmental components. These contaminants input to environment from industrial processes, hospitals and health care institutions or household sources and these pollutants can to negatively interact with environmental components. Pharmaceuticals are separated according to structure and their effects to live organisms. On the basis of drug consumption in Czech Republic the non-steroidal anti-inflammatory drugs are the most using pharmaceuticals, because these drugs can be obtain without prescriptions. The choosing analgesics for study were monitored in waste water from waste waters treatment plant (WWTP Brno – Modřice) and in surface water from two sampling sites of river Kretinka. Pharmaceuticals were monitored in surface waters in Czech Republic, in Scotland (river Thurso) and in Taiwan (river Erren, Agongdian, Yanshuei and canal of Tainan) Solid phase extraction (SPE) is used for extraction of study pharmaceutical from water system. The high performance liquid chromatography (HPLC) with diode array detection or mass spectrometry was used for determination of drugs in surface waters from Czech Republic. The water samples from Scotland and Taiwan were analysed and the high performance liquid chromatography with mass spectrometry (HPLC/MS) was used for determination of pharmaceuticals. The method of HPLC/MS enables the determination of study compounds in the very low range of concentrations (ng ? l-1). All monitored pharmaceuticals were identified and quantified in water samples from river Kretinka in Czech Republic, river Thurso (Scotland) and rivers Erren, Agongdian, Yanshuei and canal of Tainan in Taiwan and the obtained data were compared.
|
|
|
Study of Thiophene Oligo-copolymers: Synthesis and Optoelectronic Properties
Krajčovič, Jozef ; Mazal,, Ctibor (referee) ; Kapička, Vratislav (referee) ; Friedl, Zdeněk (advisor)
Thesis presents synthesis and study of thiophene monomers, oligomers and polymers. The new series of thieno[3,4-b]pyrazine copolymers based on 3-dodecylthiophene and pyrazine monomers were prepared by oxidative polymerization with FeCl3. The effective synthetic method for preparation of 3-alkylthiophenes and thiophene oligomers was developed by optimizing of Kumada cross-couplig. The mentioned method could be realized for multikilos scale with possibility of transfer to pilot plant production. The second part of thesis focuses on synthesis and study of new thiophene compounds, which consist of both 2,3-diazo-1,3-butadiene bridge with two terminal chromophores and two thiophene units linked together via -position by pyrazine or hydrazine bridge. Finally, the new type of regular alternating copolymer consists of 2,2´:5´,2´´-terthiophene-5,5´-dicarboxylic acid (TEDA) and polyethyleneoxide (PEO) was prepared. Formation of polymer nano-subunits as separated phases in solid state was confirmed by TEM.
|
|
| |
|
|
Separation of Azaarenes by High Performance Liguid Chromatography
Kočí, Kamila ; Friedl, Zdeněk (referee) ; Večeřa, Zbyněk (referee) ; Ventura, Karel (referee) ; Šimek, Zdeněk (advisor)
Under the framework of this PhD project, a study on chromatographic behaviour of selected azaarenes on octadecylsilica stationary phases during their separation by reversed phase liquid chromatography was developed. The main goal was aimed at an application of the basic RPLC principles on the retention behaviour of azaarenes including the effects such as peak tailing, peak broadening, irreproducible retention or strong retention on a stationary phase. This study was particularly focused on basic azaarenes, also called acridines, which belong to a group of persistent organic pollutants providing mutagenic and/or carcinogenic activity. The retention patterns were studied on a group of eight acridines that are often present in environmental samples polluted with polycyclic aromatic compounds. The mixture of acridines was separated under isocratic elution conditions on three octadecylsilica stationary phases using two different binary mixtures as a mobile phase. Evaluation of the surface properties of the selected stationary phases was firstly performed, followed by the separation experiments. The structure of the experiments was designed to evaluate the effect of three different factors on the retention behaviour of acridines: properties of a stationary phase, composition of a mobile phase and physical-chemical properties of acridines. The treatment of the results was based on the capacity factor values providing the best fitting and repeatability of data, but other parameters that evaluate thermodynamic and kinetic aspects of the separation process were also given. Simple correlations between the three factors and a character of retention mechanism of acridines on the given separation system were found. Application of this knowledge simplifies an optimisation process and helps to solve common separation problems for acridines, but also for other basic analytes displaying similar physical-chemical properties (Mr and pKa).
|
|
| |
|
|
Thermochemical properties of linear polynitramines
Teplá, Romana ; Pekař, Miloslav (referee) ; Friedl, Zdeněk (advisor)
The work is focused on the obtaining thermochemical properties of the linear polynitramines to predict their detonation properties. The basic thermochemical parameters are enthalpies ?f H° (298,g) in the gas and solid phase as well. The values of the enthalpy in the gas phase were obtained at a theoretical level by quantum chemical DFT calculations using both an isodesmic reactions and direct thermochemical G-Gaussian recipes. Conversion to the enthalpy in the solid phase ?f H° (298,s) was carried out using sublimation enthalpies ?s H° (298,g) obtained on the empirical level. The results were mutually compared and correlated with the structure of the linear polynitramines.
|
|
|
Thermochemistry of high nitrogen heterocyclic compounds
Bartošková, Monika ; Pekař, Miloslav (referee) ; Friedl, Zdeněk (advisor)
The prediction of detonation properties of the new generation of high-nitrogen energetic materials (HNEM) is based on knowledge of their heats of formation, which are sum of values of particular nitrogen heterocyclic fragments. The diploma thesis describes theoretical calculations of heats of formation in gas phase ?f H°(298,g) for series of azines (number of N atoms 2-6) and azoles (number of N atoms 2-5) by means of quantum chemical methods. The semiempirical methods as PM3, DFT methods utilizing isodesmic approach and finally thermochemical G-recipes were used. All calculated values of heats of formation were scrutinized and for future application to HNEM materials the DFT B3LYP/cc-pVTZ method and thermochemical recipe T1 were recommended.
|
|
|
Nitramide-based energetic materials
Křištof, Adam ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
Homolytic dissociation of the N-NO2 bond represents primary fission process of energetic materials under the influence of heat, impact, vibration and electric spark. The fission of nitramide bonds is characterized by homolytic bond dissociation energy BDE(RCON-NO2) or disproportionation bond energy DISP(RCON-NO2), which is expressed by an isodesmic reaction RCON-NO2 + SCON-H › RCON-H + SCON NO2, where SCON NO2 is a standard nitramide (1-nitropiperidin-2-on, NPO). This kind of virtual chemical calculation cancels the effect of electron correlation, accompanying the theoretical calculations of free radicals. In this thesis, the homolytic dissociation bond energy BDE(RCON-NO2) and disproportionation bond energy DISP(RCON-NO2) were evaluated for 13 cyclic nitramides using the DFT B3LYP/6-311+G(d,p) method and at the same time the total charges of corresponding nitro groups Q(NO2) were calculated by DFT B3LYP/6-31G(d,p) method. The evaluated BDE and DISP energies were correlated with detonation parameters as squares of detonation velocities and detonation heats. The resulting relationships allow a more detailed description of dependence between the molecular structure of evaluated nitramides and their explosive properties.
|
guest ::
RSS feed.