Conversão catalítica de isopropanol e 1-butanol: emprego de magnetita como catalisador em reator de fluxo contínuo de leito fixo

Abstract

A continuous flow, fixed bed reactor type system was implemented without a research group in order to conduct the study in heterogeneous catalysis, in a catalytic potentiation of metal oxides in conversion, degradation and oxidation chains of compounds organic. such as alcohol. The material used in this work to evaluate the catalytic potential in the conversion of alkaline was magnetite. The magnetite (Fe3O4) was synthesized in aqueous medium by means of the coprecipitation method. The material was evaluated in order to oxidize isopropanol and 1-butanol in an inert and oxidizing atmosphere. The formation of the magnetite was investigated through its morphological and structural properties with the use of scanning electron microscopy and X-ray diffraction techniques. With the reactions performed at different temperatures, it was necessary to determine the thermal stability of the nanoparticles, using thermogravimetry and differential scanning calorimetry techniques. The morphology of the magnetite was verified through the scanning electron microscopy technique, which showed a heterogeneity in morphology and size distribution. The structure of the magnetite, analyzed by X-ray diffraction, indicated the presence of a single crystallographic phase related to magnetite, whose symmetry group is cubic, Fd3m. The size of domains with estimated crystallographic consistency using the halfheight width is 20.30 nm. By means of the infrared spectroscopy technique, two bands were identified, one in 424 cm -1 in 534 cm -1 corresponding to the deformation and stretching of the Fe-O bonds associated with the octahedral and tetrahedral sites, respectively, of the inverted spinel structure and bands between 1630 cm -1 and 3400 cm -1 which are typical regions of the presence of adsorbed water or hydroxyl groups on the surface of the magnetite. The thermal stability of the magnetite evaluated by thermogravimetry (TG) and differential scanning calorimetry did not demonstrate crystalline phase transitions at a temperature of 350 °C. The catalytic potential of the magnetite was evaluated by means of reactions between magnetite and isopropanol and 1-butanol, which are used as reactors in fixed bed reactor and continuous flow with temperature variation and in inert and oxidizing atmosphere. The reaction, monitored by gas chromatography, showed formation of propanone and butanal. The continuous flow system with fixed bed reactor demonstrated efficiency in its use for conversion reactions.