|
| |
|
| |
|
|
Dissociation Constants of Perfluorocarboxylic Acids
Vlasáková, Tereza ; Nesměrák, Karel (advisor) ; Rychlovský, Petr (referee)
Bachelor's thesis is concerned on dissociation exponents of perfluoroalkanoic acids. The published values of dissociation exponents have been reviewed. The dissociation exponents of six selected perfluoroalkanoic acids (from perfluoropentanoic to perfluorodecanoic acid) were determined using neutralization potentiometric titration method. The values of determined dissociation exponents ranges from pKa = 2,17 to 2,44, and they are in agreement with known data. The decrease of value of dissociation exponent with increasing number of carbon in alkyl chain has been observed. Also, the increase of values of dissociation exponents of perfluoroalkanoic acids in comparison with theirs nonfluorinated analogs has been confirmed.
|
|
|
Synthesis of phosphinic acids
Kruliš, Tomáš ; Kubíček, Vojtěch (advisor) ; Schulz, Jiří (referee)
Two types of phosphinic acids were prepared: N,N-bis(carboxymethyl)aminomethyl phosphinic acid and carboxyethylphosphinic acid. Afterwards they were used to synthesize bisphosphinic acids: 1-hydroxy-ethan-1,1-bis[N,N-bis(carboxymethyl)aminomethyl phosphinic] acid and 1-hydroxy-ethan-1,1-bis(carboxyethyl)phosphinic acid. All compounds were characterized by NMR and mass spectroscopy. N,N-bis(carboxymethyl)aminomethylphosphinic acid was synthesized by Mannich type reaction. Carboxyethylphosphinic acid was prepared by alkylation of bis(trimethylsilyloxy)phosphine. Both bisphosphinic acids were prepared by reaction of silylesters of phosphinic acids with acetylchloride. All compounds were prepared in moderate or good yields. Keywords: Organophosphorus synthesis, phosphinic acids, bisphosphinic acids
|
|
|
Study of thermodynamic stability of complexes with polydentate ligands
Böhmová, Zuzana ; Kubíček, Vojtěch (advisor) ; Vojtíšek, Pavel (referee)
Acid-base and coordination properties of macrocyclic ligand 1-oxa-4,7- diazacyclononane-4,7-bis(methylenephosphonic acid) were investigated. Protonation constants and stability constants with Ca2+ , Mg2+ , Cu2+ , Zn2+ , Mn2+ a Ga3+ metal ions were determined by potentiometry. Keywords Potentiometry, coordination chemistry, azacycles.
|
|
|
Device for measurement of electrochemical cells characteristics by the cyclic voltammetry
Kučera, Vojtěch ; Bilko, Radek (referee) ; Lábus, Radek (advisor)
The thesis deals with observation of cells parameters. One of the potential solutions for observing the characteristics of cells are utilization the electrochemical analyse called voltametry. Its fundamental consists of loading variable voltage in between two electrodes dipped in electrolytic solution and monitoring flowing current. The point of the thesis is to build up the measuring workplace, which can provide this measurement. We suggest utilization of modern laboratory technique and connection the measuring instruments with PC. The first part of the thesis deals with theoretical knowledge of used functions and describes theirs mathematics definitions. The second part deals with proceeding of workplace realization, instrument connection with PC and development application in computer’s language. Result is measuring workplace, which can provide observing cells according to entered parameters.
|
|
|
Acidobasic behavior of carboxymethylcellulose solutions
Teslíková, Ivana ; Kislinger, Jiří (referee) ; Janeček, Jiří (advisor)
This work concerns with the study of acidobasic behavior of solutions of sodium salts of carboxymethylcellulose (CMC-Na). This behavior was investigated using acidimetric titrations of the salt solutions with potentiometric and conductometric indications. In order to determine the content of carboxylic groups in two different samples of CMC-Na (M1=90 kDa, DS1=0.7; M2=700 kDa, DS2=0.9), we employed the method of Ray von Wandruzska, originally proposed for the determination of the acidity of humic substances. The values of the degree of substitution (DS) obtained using this method correspond to the values declared by the producer. The small differences (of the order few percentage points) can be attributed to the humidity of the samples. The acidimetric titrations were performed also for solutions with different ionic strengths. There is an apparent effect of the ionic strength on the shape of titration curves; nevertheless these data were not used for any theoretical interpretation.
|
|
|
Mléčné kvašení červené řepy
Pavloušková, Eva
This thesis, themed "Lactic fermentation of beetroot", was elaborated on the Faculty of Horticulture in Lednice between 2012 and 2014. The theoretical part includes characteristics of beetroot and lactic fermentation. The practical part is focused on eight created beverages with different ratios of fermented beetroot juice and other vegetable and fruit components. An analysis of nutrition components based on levels of soluble dry matter, organic acids and chlorides, and the sensorial evaluation was made for forementioned fermented and mixed beverages created. On the grounds of results it is stated that lactic fermented beetroot juice and its use in beverages is another valid option of technologic processing of beetroot.
|
|
| |
|
| |
guest ::
