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The Study of Ethyllactate Synthesis from Lactic Acide Salts
Hlavatá, Daniela ; Figalla, Silvestr (referee) ; Petrůj, Jaroslav (advisor)
This diploma thesis deals with senthesis of lactic acid ethyl ester from slats of lactic acid. The literature review has been processed in the theoretical part of the diploma thesis. It is focused on manufacturing technologies of lactic acid esters, mainly on ethyl lactate by conventional and non-conventional ways of producing. Also the literature review involves producing of lactic acid and slats of lactic acid by fermentation because subsequently is possible produce ethyl lactate from that two substances. The laboratory apparatus for preparation of ethyl lactate and methyl lactate has been designed, realized and verificated function of it in the experimental part. There were carried out laboratory experimnets for production ethyl lactate and methyl lactate in this apparaturs.
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Synthesis and Characterization of PVAl Acrylic Esters
Hynštová, Karolína ; Jančovičová, Viera (referee) ; Dzik, Petr (advisor)
The diploma thesis deals with a detailed study of he esterification reaction between PVAl and acrylic and methacrylic acids. Tha goal is to prepared PVAl-based macromers bearing (meth)acrylic moieties bound to PVAl macromolecular backbone. Attention will be paid especially to equlibrium establishing times and to the influence of reaction mixture composition on the properties of resulting products.
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Chemické modifikace bilinových barviv
VOMÁČKOVÁ, Hana
This thesis deals with isolation of phycocyanobilin from cyanobacteria Thermosynechococcus elongatus and its purification with TLC. Purified phycocyanobilin was esterified using Fischer esterification method. The esterification method in this thesis was modified by using dichlormethan as solvent. The results were analysed by HPLC method. Pilot experiments dealing with insertion of esterified phycobilins into self-organized aggregates of bacteriochlorophyll c were carried out.
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In-matrix esterification of polar carboxylic acids in urine
Anýžová, Petra ; Mráz, Jaroslav (advisor) ; Feltl, Ladislav (referee)
A set of 15 carboxylic acids of various structural types was used to test a new procedure of esterification of these substances in the urine without previous extraction. The acids were first measured by a reference method without the matrix, and then by a procedure, where lyophilized urine was treated with derivatizing reagent alcohol·HCl, which was then evaporated, the residue dissolved in water, esters extracted into an organic solvent and subsequently determined by GC/FID and GC/MS. The work is mainly focused on 2-hydroxyethyl- and carboxymethyl-mercapturic acids, but the procedure was also tested on di-, tri- and hydroxy-carboxylic acids, known as physiological urinary components or markers of metabolic disorders. Key words: carboxylic acids mecapturic acids freeze-dried urine esterification gas chromatography
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Preparation of Ethyl 2-acetoxypropanoate
Kučerová, Eliška ; Pospíšilová, Aneta (referee) ; Figalla, Silvestr (advisor)
The bachelor thesis focuses on the preparation of ethyl 2-acetoxypropanoate as a potential nonpolar biosolvent. Selected preparation should provide the highest yield possible. For this purpose, a theoretical review of possible syntheses was developed, with emphasis on syntheses based on acetylation of ethyl lactate. The experimental part of the work then focuses in more detail on the possibility of isolating ethyl 2-acetoxypropanoate from the reaction mixture. Product isolation was verified by fractional distillation and extraction method. In the isolated product, the basic physical properties were determined and the spectrum measured by Fourier transformation infrared spectroscopy. Furthermore, the hydrolytic stability of ethyl 2-acetoxypropanoate was investigated and a series of calorimetric measurements were performed. From these measurements, the effect of reaction temperature on reaction rate and product conversion and the effect of catalyst presence was assessed.
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Energy use of biomass
Ošťádal, Michal ; Elbl, Patrik (referee) ; Baláš, Marek (advisor)
The main aim of this bachelor thesis is to search for technologies for biomass conversion with subsequent energy utilization. At the beginning of the work is analyzed the nature of biomass as an energy source. The next part deals with individual technologies. The following section deals with combustion and biogas chains. The penultimate chapter deals with chosen energy sources. The last chapter is statistical processing of emissions, mining, electricity and heat production from renewable sources and biomass.
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New Processes of Lactid Acid Polymers Preparation
Figalla, Silvestr ; Svěrák, Tomáš (referee) ; Herink,, Tomáš (referee) ; Petrůj, Jaroslav (advisor)
The work focuses on new processes for the preparation of lactic acid derivatives. The main objective was to verify the feasibility of preparing high molecular weight polylactide using ethyl lactate as a precursor of lactide synthesis. Part of the work is devoted to the new ethyl lactate synthesis method. The experimental part of the thesis is divided into partial key steps on the way from the lactic acid to the high molecular polylactide. The preparation of anhydrous ethyl ester of lactic acid (EtLA) was solved in an innovative way using alcoholysis of the oligomeric lactic acid. A kinetic model for isothermal alcoholysis and equimolar reactants ratio was derived from this method. The ethyl lactate was oligomerized by transesterification into the low and high molecular weight oligomer with the help of newly found catalysts suitable for the reaction medium. Stannous lactate was used as catalyst for oligomerization of the low molecular weight polymer suitable for the preparation of lactide (Mn 1000 g.mol-1). Experimental polymerization of ethyl lactate into high molecular weight product in tens of kDa has been investigated with newly synthesized tetraethyllactoyl titanate, Ti(EtLA)4. The laboratory method was derived for the depolymerization of the oligomer into lactide. Optimal conditions found for lactidation are as follow: temperature 225 ° C, pressure 2 kPa, catalysis 0,05 mol% of stannous lactate (with respect to oligomer lactate units). The prepared lactide was refined to polymer grade purity by distillation and subsequent recrystallization from ethyl acetate and toluene. The method for the preparation of high molecular weight PLA through ROP polymerization of lactide has been optimized. By optimization, suitable catalyst concentration was found in combination with the polymerization temperature and the polymerization length. An equimolar mixture of Tin 2-ethylhexanoate and 1-decanol was used as the catalytic system. The optimal ROP conditions for achieving the maximum molecular weight and suppressed polymer coloration (yellowing) are: catalyst concentration 0,01 mol%, temperature 160 °C, and polymerization length 4 hours. PLA with molecular weight Mw= 447 ± 7,8 kg.mol-1 was prepared at these conditions and good repeatability of the result was achieved. The effect of naturally occurring lactide contaminants and their influence on the course and ROP result was experimentally verified on the optimized polymerization system. The purpose was to explore the effect of lactide contamination with water and ethanol as natural lactide contaminants. The results clearly confirm the orderly lower sensitivity of the polymerization system for the presence of ethanol as compared to water contamination. In the case of the presence of water, the course and the result of the polymerization in terms of both the conversion and achieved molecular weights are negatively affected, even when the water content is in the order of 0,001%. Conversely, the presence of ethanol has a positive effect on lactide conversion and polymer polydispersity. Lactides with an alcohol content of about one-tenth of a percent are suitable to reach molecular weights of PLA similar to commercially available products. This difference shoves a significant advantage in the proposed technology of preparing PLA from ethyl lactate, especially for easier purification of crude lactide into polymer grade purity.
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Izolace fykobilinů ze sinice \kur{Synechocystis} a možnost jejich následné esterifikace
KALKUŠ, Milan
This thesis describes phycobilins, their biosynthesis, properties and functions during photosynthesis. Their esters could be used to produce artificial self-assembling lightharvesting antennae. Pigments with similar structures (tetrapyroles) are also described. The experimental part describes the isolation of phycobilins from the cyanobacterium Synechocystis by cleavage with hydrochloric acid, the analysis of obtained pigments by TLC and HPLC methods and esterification of purified phycobilins with butan-1-ol.
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In-matrix esterification of polar carboxylic acids in urine
Anýžová, Petra ; Mráz, Jaroslav (advisor) ; Feltl, Ladislav (referee)
A set of 15 carboxylic acids of various structural types was used to test a new procedure of esterification of these substances in the urine without previous extraction. The acids were first measured by a reference method without the matrix, and then by a procedure, where lyophilized urine was treated with derivatizing reagent alcohol·HCl, which was then evaporated, the residue dissolved in water, esters extracted into an organic solvent and subsequently determined by GC/FID and GC/MS. The work is mainly focused on 2-hydroxyethyl- and carboxymethyl-mercapturic acids, but the procedure was also tested on di-, tri- and hydroxy-carboxylic acids, known as physiological urinary components or markers of metabolic disorders. Key words: carboxylic acids mecapturic acids freeze-dried urine esterification gas chromatography
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