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The acid which is analogous to the next member of the diphenylpolyenes, 1,4-diphenylbutadiene, is muconic acid. This acid has been chosen to be investigated in an effort to isolate all the stereoisomers of a set containing more than two isomers.

Creation of electronic materials for chemistry education Bc. Petra Váňová Faculty of Science, Charles University in Prague, 2014 The theme of my thesis is formation of educational instruments/tools for distance education and e-learning which at the same time can be inspirational for teachers of present learning. The theoretical section elaborates on the problems of distance education and e-learning. Furthermore, it describes Moodle, the system for teaching management. For the purpose of the applied section two teaching units were created during the class of Didactics of Organic Chemistry (MC280P06) at Department of Teaching and Didactics of Chemistry, Faculty of Science, Charles University in Prague. The two units focus on the problematic of carboxylic acids and their derivatives. Beside the information about these topics, the contents of the teaching units should provide the students with an insight into modern study tools which increase the effectiveness of distance education as well as present learning. The teaching units are supplemented by study texts, Power Point presentations, handouts with key answers, projects/designs of chemical experiments applying theoretical knowledge to practical level, and a test designed for verifying the improvement of the course participants. The study tools were...

This project studied the biodegradation of a plasticizer, di-(2-ethylhexyl) adipate (DEHA), by two mammalian cell lines, HepG2 and WIF-B, in vitro . An MTT assay showed that DEHA had a toxic effect on both cell lines. Despite this, both hepatocyte cell lines successfully degraded the plasticizer. Metabolites were identified and quantified by gas chromatography. HepG2 cells showed minimal alcohol dehydrogense activity and this resulted in the accumulation of 2-ethylhexanol. WIF-B cells were able to breakdown the alcohol and produced 2-ethylhexanoic acid. It is important to note that an enzyme was essential for this step in the degradation of the plasticizer, as this proves that it was biodegradation and not physical degradation. By comparing the metabolites formed and the order of their appearance, the degradation pathway in these mammalian cells was found to be similar to the established degradation pathways for bacteria, fungi and yeast.

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published_or_final_version / Biological Sciences / Master / Master of Philosophy

VLE data is essential for the design and optimisation of industrial separation processes. Carboxylic acids are of significant interest because of their importance in both industrial and biological processes. Carboxylic acids are used as raw materials for a wide range of products, which include soaps , detergents, nylon , biodegradable plastics, medical drugs and food additives, They are also used both as solvents and as additives and co solvents under a wide range of conditions. Carboxylic acids exhibit strong self and cross -association through hydrogen bonds in both liquid and vapour phases. A thorough understanding of how these molecules interact both with themselves and with other solvents becomes necessary if existing processes may be optimised and new processes developed. Vapour-liquid equilibrium (VLE) data were measured for carboxylic acid systems ranging from C3 to C6• New vapour-liquid equilibrium data were measured for the following binary carboxylic acid systems: • Propionic acid + Hexanoic acid at 20 kPa, 403.15 K, 408.15 K and 413.15 K. • Isobutyric acid + Hexanoic acids at 20 kPa, 413.15 K and 423.15 K. • Valerie acid + Hexanoic acid at 15 kPa, 423 .15 K and 433.15 K. • Hexanoic acid + Heptanoic acid at 10 kPa and 443.15 K. A highly refined dynamic VLE Still by Raal (Raal and Muhlbauer [1998]) was used to undertake the VLE measurements. The still was operated either isothermally or isobarically using a computer control scheme. The isobaric and isothermal control was measured to be ±0.03 kPa and ±0.02 K respectively. The experimental procedure was verified with the highly volatile cyclohexane (l) + ethanol (2) system. The cyclohexane (l) + ethanol (2) measured VLE data was found to be in good agreement with that of Joseph (2001) and passed both the direct test and point test for thermodynamic consistency. A high degree of confidence was then placed on the equipment set-up and experimental procedure, as well as the new carboxylic acids VLE data . The VLE data for all the systems measured were modelled. Two data reduction methods were used: I. The combined ( r- ¢ ) method u. The direct method (¢ - ¢ ) method. In the combined method, the vapour phase non-idea lity was corrected using the Pitzer-Curl (1957) correlation and the Hayden and O' Connell (1975) chemical theory approach. Three liquid phase activity coefficient models were used namely the Wilson, NRTL, and UNIQUAC equations. The Peng-Robinson equation of state (Peng and Robinson [1976]) in combination with the Twu and Coon mixin g rule was used in the direct method. Thermodynamic consistency tests were done on all the systems measured. The point test (Van Ness et a!. [1973]) and the direct test Van Ness ([ 1995]) were used for consistency tests . The direct test could not be carried out on the carboxylic acids data because of the model's inability to adequately characterise the experimental activity coefficients. Generally the models fitted the data well but failed to accurately predict the "S" shape of the carboxylic acids phase diagrams. Considerable work still exists for further investigation into carboxylic acids. Currently, many experimentalists are working in this area . Penget a!. (2004) present ed their progress on developing an equation of state incorporating chemical theory to specifically handle carboxylic acids at the ICCT conference in Beijing, 2004. Raal and Clifford (University of Kwa-Zulu Natal, Thermodynamics Research Unit) are currently developing activity coefficient models incorporating chemical theory for a binary mixture of carboxylic acids. This work is part of the continuing research to under stand the phase behaviour of carboxylic acids. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2005.

Contrairement aux effluents aqueux issus du procédé PUREX, les effluents issus des procédés de séparation poussée actuellement en développement pour séparer les actinides mineurs contiennent des réactifs organiques en quantité importante. Afin de minimiser l'impact de ces composés sur les étapes en aval du procédé et pour respecter les normes de rejet, la destruction de ces composés est indispensable. De par des conditions opératoires et de sûreté adaptées au domaine du nucléaire, la voie sonochimique apparaît comme une solution très prometteuse pour l'élimination des espèces organiques. La propagation d'une onde ultrasonore dans un milieu liquide se traduit par l'apparition de bulles de cavitation qui vont croître et imploser, engendrant ainsi des conditions locales de température et pression extrêmes. Chaque bulle de cavitation peut être alors considérée comme un microréacteur à haute température et haute pression capable de détruire, sans ajout de réactifs spécifiques, les molécules organiques. Les premières études portant sur l'influence de la fréquence ultrasonore sur la sonolyse et la sonoluminescence de l'acide formique ont montré que la dégradation de l'acide formique se déroule à l'interface liquide/bulle quelle que soit la fréquence ultrasonore. La différence notable entre les ultrasons basse et haute fréquence réside principalement dans l'initiation de réactions secondaires observées seulement entre 200 et 1057 kHz. Malgré une activité sonochimique bien plus importante à haute fréquence, l'utilisation des ultrasons seuls pour traiter les effluents issus des procédés de séparation avancée ne peut être envisagée de par la concentration élevée en acides carboxyliques. Afin d'augmenter l'efficacité des réactions sonochimiques, l'ajout de catalyseurs à base de platine supporté a donc été étudié. Dans ces conditions, il s'avère que le couplage ultrasons/catalyseurs permet une augmentation considérable des cinétiques de dégradation des acides carboxyliques. / Unlike aqueous effluents from the PUREX process, aqueous effluents from advanced separation processes developed to separate the minor actinides (Am, Cm) contain organic reagents in large amounts. To minimize the impact of these organic compounds on the next steps of the process, and to respect standard discharges, it is necessary to develop new techniques of degradation of organic compounds. Sonochemistry appears as a very promising solution to eliminate organic species in aqueous nuclear effluents. Indeed, the propagation of an ultrasonic wave in a liquid medium induces the appearance of cavitation bubbles which will quickly grow and implode, causing local conditions and extreme temperatures and pressures. Each cavitation bubble can then be considered as a microreactor at high temperature and high pressure able to destroy organic molecules without the addition of specific reagents. The first studies on the effect of ultrasonic frequency on sonoluminescence and sonolysis of formic acid have shown that the degradation of formic acid occurs at the bubble/liquid interface. The most striking difference between low-frequency and high-frequency ultrasound is that the sonolysis of HCOOH at high ultrasonic frequencies initiates secondary reactions not observed at 20 kHz. However, despite a much higher sonochemical activity at high frequency, highly concentrated carboxylic acids in the aqueous effluents from advanced separation processes cannot be destroyed by ultrasound alone. To increase the efficiency of sonochemical reactions, the addition of supported platinum catalysts has been studied. In these conditions, an increase of the kinetics of destruction of carboxylic acids such as oxalic acid is observed.