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Možnosti aplikace mastných kyselin při ukončení alkoholové fermentace
Černoch, Michal
This bachelor thesis deals with the issue of higher medium chain fatty acids (MCFA) and their effect on the termination of alcoholic fermentation. The literature describes fatty acids, carbonyl compounds, alcoholic fermentation and sulfur dioxide in general. In the experimental part, an experiment was carried out in which MCFA was applied and the effect on the end of fermentation and the content of carbonyl compounds was observed. The experiment was divided into two application variants. The main difference was that variant A was the applied MCFA to the wine lees, and wine was racked after three days, variant B then consisted in the application of MCFA immediately after racking of the wine. Chemical and sensory analysis was performered then. The effectiveness of MCFA in inhibiting microorganism was confirmed by chemical analysis. Within the total carbonyl compounds, the content was lower in variant B than in variant A but the difference was negligible. Compared to wines produced by standard technology, the wines where MCFA was applied the content was rapidly lower. Sensory analysis has shown that the recommended dose of MCFA does not affect organoleptic properties. The wines were fruity, with tones of citrus and tropical fruits.
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Sulfur-based reagents for nucleophilic and radical introduction of tetrafluoroethyl and tetrafluoroethylene groups
Chernykh, Yana ; Beier, Petr (advisor) ; Kvíčala, Jaroslav (referee) ; Církva, Vladimír (referee)
Charles University in Prague, Faculty of Science Department of Organic Chemistry Ing. Yana Chernykh Sulfur-Based Reagents for Nucleophilic and Radical Introduction of Tetrafluoroethyl and Tetrafluoroethylene Groups Ph.D. Thesis Prague 2014 ABSTRACT This project was aimed at developing new methodologies for selective introduction of tetrafluoroethyl and tetrafluoroethylene groups into organic molecules. The study was focused on reactivities of fluorinated sulfones and sulfides as tetrafluoroalkylation reagents. In the Introduction part of the thesis, main aspects of organofluorine chemistry are outlined, illustrating beneficial effects of fluorine atoms on physical, chemical and biological properties of organic compounds. General synthetic methods for the selective introduction of fluorine atoms and fluoroalkyl groups to organic molecules are described. Particular attention is given to reactivity and applications of CF2CF2-containing compounds, indicating challenges in synthetic approaches toward tetrafluoroalkylation. The Results and discussion part describes reactivities of four new fluorinated organosulfur reagents as tetrafluoroethyl and tetrafluoroethylene building blocks. The application of these reagents as various carbanionic or radical synthons proved to be effective for the incorporation of CF2CF2...
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Frustrated Lewis pairs-assisted reduction of carbonyl compounds
Marek, Aleš ; Pedersen, M. H. F.
An alternative and robust method for the reduction of carbonyl groups by frustrated Lewis pairs (FLPs) is reported in this paper. With its very mild reaction conditions, good to excellent yields, absolute regioselectivity and the non-metallic character of the reagent, it provides an excellent tool for 1H, 2H as well as 3H chemistry. It is a new strategy for the one-pot synthesis of aromatic alcohols selectively labeled with heavy isotopes of hydrogen.
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