Národní úložiště šedé literatury Nalezeno 58 záznamů.  1 - 10dalšíkonec  přejít na záznam: Hledání trvalo 0.00 vteřin. 
Reaction Kinetic Study of Triterpene Hydrogenation using a Heterogeneous Catalyst.
Stavárek, Petr ; Ujčić, Massimo ; Lali, Farzad ; Magne, J.
This research focuses on reaction kinetic study of three-phase catalytic hydrogenation on a heterogeneous Ru/C catalyst.
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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.
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Induced Oscillatory Behaviour During 2-Methylpropene (Isobutene) Hydrogenation in a Packed Bed Microreactor.
Vajglová, Zuzana ; Stavárek, Petr ; Jiřičný, Vladimír ; Kolena, J.
This contribution focuses on the induced oscillatory behaviour observed during the continuous hydrogenation of 2MP in a packed bed microreactor. Induced reproducible oscillations have been studied using the on-line gas chromatograph (GC-FID/TCD) and a catalyst bed temperature monitoring. Effects of the temperature, thermal conductivity and space velocity on the properties of induced oscillations have been investigated in detail. The study results revealed extremely high sensitivity of the oscillatory behaviour to the heat transfer conditions in the system. Experimental tests focusing on the space velocity effect revealed a significant influence on the oscillation amplitude height and period phase length with the high reaction rate. Based on the character of the induced oscillations, they have been classified as thermo-kinetic oscillations1 as they are resulting from the interaction between the exothermic reaction, heat transfer and a reversible decrease in the catalyst activity.
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Evaluation of Residence Time Distribution in Millireactor with Laminar Flow: Comparison of Experiments, CFD and Laminar Flow Model.
Hejda, Stanislav ; Trávníčková, Tereza ; Havlica, Jaromír ; Stavárek, Petr ; Staněk, Vladimír
We present a study of RTD in the case of small straight channels. RTD measurements in liquid phase were performed by a dye injection and its absorbance measurements with a spectrometer at the inlet and the outlet of the reactor. The method consistency was confirmed by a dye mass balance between inlet and outlet which was satisfied with an error of 5% rel. The RTD in the measured section was characterized by so called e-curve E (t), mean residence time and Peclet number for different flow conditions (Reynold´s numbers). The RTD data for various channel lengths and liquid flow rates were compared.
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