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The cataytic performance of Mg/Al and Mg/Fe mixed oxides in transesterification in flow reactor
Autoři: Vávra Aleš | Hájek Martin | Frolich Karel | Kocík Jaroslav | Jílková Alena
Rok: 2018
Druh publikace: ostatní - článek ve sborníku
Název zdroje: 13th conference on sustainable development of energy, water and environment systems : book of abstracts
Název nakladatele: University of Zagreb
Místo vydání: Zagreb
Strana od-do: 286-286
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng The cataytic performance of Mg/Al and Mg/Fe mixed oxides in transesterification in flow reactor This study is focused on the test of the Mg-Fe and Mg-Al mixed oxides, as heterogeneous catalyst, in the transesterification of rapeseed oil with methanol in the flow reactor. The major advantages of flow reactor are faster reactions, cleaner products, quick reaction optimization, easy scale-up and possibility to use online analysing of products. The mixed oxides were synthesized from the layered double hydroxides (hydrotalcites) by calcination at 500 °C with the constant molar ratio 3:1 (determined by ICP). All synthesized materials were characterized by several techniques such as X-ray diffraction, thermogravimetric analysis, specific surface area, temperature programmed desorption (TPD), diffuse reflectance infrared Fourier transform spectroscopy and SEM. The characterisation methods confirmed the formation of hydrotalcites and also mixed oxides. The transesterification was carried out at different weight hour space velocity – WHSV (1, 2 and 3 h-1) and different reaction temperatures (115, 150 and 200 °C), each parameter was tested for 32 h. Moreover, the stability of catalyst was tested by the determination of metals in reaction mixture, which is very often omitted in open literature. The ester yield increased (from 26 to 60 % for Mg-Al mixed oxides) with decreasing WHSV and with increasing reaction temperature (from 65 % to 97 % for Mg-Al mixed oxides). The Mg-Al mixed oxides were more active for all WHSV and temperatures 115 and 150 °C due to lower crystallite size and particularly higher concentration of active basic species (determined by TDP-CO2). The relations between material properties and catalyst activity are described. In the case of reaction temperature 200 °C, the catalyst activity was almost the same (the ester yield 97%). The long time catalytic test (300 h) for verification of catalyst lifetime and stability was also carried out. The ester yield was 90 % for Mg-Al and 55 % for Mg-Fe for long catalyst tests, so stability of the catalysts was prove transesterification; mixed oxides; Mg-Al; Mg-Fe; flow reactor