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Quaternary Ammonium Salts in Asymmetric Hydrogenations – Additives, Reaction and Immobilization Media
Floriš, T. ; Klusoň, Petr ; Muldoon, M.J.
The inhibited catalytic activity of Ru-BINAP in MAA hydrogenation through ILs based on anion derivates of acids with higher pKa revealed a side way in the application of the ILs produces from renewable sources, (chiral) carboxylates (betaine, lactates) in genaral. On the other hand the employment of structurally modified quaternary ammonium cations seems to be the perspective route not only in optical yeld increase. Thus quaternary ammonium bromides such as chorides satisfied the reaction parameters enhancement. On the basis of our previous results, envirnmentaly benign choline chloride was applied as a crucial additive in optimized solvent system composed of methanol, CO2 and water.
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Catalysts for Biodiesel Production from Low-Grade Raw Materials
Jeřábek, Karel ; Holub, Ladislav ; Hanková, Libuše
In the biodiesel production from low-cost materials containing free fatty acids could be for their esterification used ion exchanger catalysts. They lower amount of the produced wastes and as heterogeneous catalysts they allow carrying the process in flow-through reactor. However, their application properties strongly depend on the methanol concentration in the reaction mixture and the character of this influence is different for different morphologies of the ion exchanger polymer skeleton. Good knowledge of these effects is important for optimization of the production process.
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Renewable Source of Energy – Gasification of Biomass with Co-generation of Heat and Electricity
Šulc, J. ; Richter, M. ; Svoboda, Karel ; Vacek, J.
Co-generation processes based on combined production of heat and electricity from biomass will be preferred. Biomass gasification (mainly woody biomass), even in a smaller scale, offers relatively high efficiency of power generation, higher than commonly attained in combustion processes. Gasification of biomass produces raw fuel gas, which can be used, after appropriate cleaning, as a fuel in internal combustion engine or (after compression) gas turbine. The gasifier is based on co-current flow of gas and solid phase, up-flowing biomass (wood pellets) driven by a vertical screw and gasification by air. The gas cleaning is based on separation of dust, oil and water scrubbing for Removal of tar, soot, organics and ammonia. Electricity will be produced from the clean fuel gas by means of a gas engine and power(electricity) generator.
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Effect of pH Adjustment on Hexane Extract Composition at Liquid-Liquid Etraction
Rousková, Milena ; Heyberger, Aleš ; Tříska, Jan ; Cvengroš, J. ; Kleinová, A.
Tall soap is a by-product of the sulphate process in pulp and paper production. In the Czech Republic it is utilized only as an energy source. It can serve also as a source of valuable components, e.g. phytosterols, which have positive effect on human health (decreasing of cholesterol content in blood, cardiovascular diseases, some types of cancer etc.). These substances can be separated by liquid-liquid extraction. Its applicability is limited by high content of emulsifiers in the raw material. It can be eliminated by decreasing the pH of the tall soap solution by mineral acid. This partial acidification has a positive effect on both hydrodynamics of the extraction process and the increase of distribution coefficients of individual compound groups, which can affect the composition of the output phases. Further experiments were carried out to refine phytosterols by the use of wiped-film molecular evaporator. Two different levels of pH of processed tall soap were used.
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