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Non-Thermal Crystallization of TiO2 Thin Films using Supercritical Carbon Dioxide Modified by Ethanol-Water Mixture.
Sajfrtová, Marie ; Cerhová, Marie ; Jandová, Věra ; Dřínek, Vladislav ; Matějová, L. ; Daniš, S.
In this work, the scCO2 modified by mixture of water and ethanol was used for a preparation of crystalline and pure nanostructured TiO2 thin films in one step processing. All the experiments were performed over precursor titania thin films prepared by reverse micelles assisted sol-gel method, using hardly removable nonionic surfactant Triton X-114, however, forming uniform nano-domains. The effect of temperature (40-150 °C), pressure (10-30 MPa), modifier composition \n(20, 50 and 80 % w/w of water in ethanol) and concentration inscCO2 (5-15 wt. %) and consumed amount of solvent (50-200 g) on microstructure and purity\nof TiO2 thin films was thoroughly studied by means of Raman spectroscopy, X-ray diffraction, and contact angle measurements.
Plný tet: SKMBT_C22018100509361 -  PDF
Plný text: content.csg - PDF
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Kinetics of Supercritical Fluid Extraction of Carotenoids from Microalgae and Plants.
Sovová, Helena
This contribution summarizes previous results of our analysis of data on the supercritical fluid extraction of carotenoids from microalgae, adds comparison of the mathematical model with newly available experimental data, and applies the model on CO2 extraction of carotenoids from different plants, where equivalent extraction mechanisms are supposed to be valid.
Plný tet: SKMBT_C22018100509360 - PDF
Plný text: content.csg - PDF
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Kinetic Modeling of the Catalytic Hydrogenation of Nitrile Esters to Amino Esters.
Lali, Farzad ; Stavárek, Petr ; Ujčić, Massimo ; Laube, Marek ; Devaux, J.-F. D. ; Dubois, J.-L. D.
The catalytic hydrogenation of nitrile esters to amino esters was studied.Amino-esters are alternative monomers to produce these polymers. The hydrogenation of nitrile ester was performed in a stirred tank reactor. The mixing of the fluids was carried out using a gas induction stirrer with a hollow shaft. An appropriate amount of ammonia has to be dissolved into the reaction mixture in order to avoid side or consecutive reactions, whereas the starting material nitrile ester was diluted by applying methyl-cyclohexane as solvent.The influence of the amount of dissolved ammonia and the hydrogen solubility in the reactants and in the chosen solvent were considered in this study. A reaction mechanism is proposed a mathematical model, which describes the proposed reaction mechanism of intermediate species and products was proposed for this hydrogenation reaction. The data were fitted using the least square method and the relevant kinetic rate constants were determined.
Plný tet: SKMBT_C22018100509340 - PDF
Plný text: content.csg - PDF
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