Síntese e avaliação de óxido de ferro suportado em carvão ativado polimérico como catalisador na desidrogenação do etilbenzeno
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Universidade Federal de Goiás
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In this work, activated carbon were synthesized through carbonization
of a polymer, containing iron oxides with and without copper. The precursor
of activated carbon was a styrene?divinylbenzene copolymer (Sty?DVB)
synthesized through suspension polymerization, in the presence of inert
diluentes to obtain a macroporous structure. The resin was sulfonated with
sulfuric acid, in the presence of dichloroethane. For the synthesis of the
supported catalysts, on first it was carried out oxide precipitation in the
sulfonated resin and later a thermal treatment to obtain the carbonizated
structures. The oxides synthesis were accomplished in three stages: the)
incorporation of Fe2+
ions with or without Cu2+
in the resin by ion exchange;
b) washing to remove the íons that were not adsorbed; c) coprecipitation in
alkaline and oxidant solution. The thermal treatment consisted in calcination
of polymer/oxide composite at 250 ºC, carbonization at 900 ºC and activation
at 900 ºC with steam. The effect of copper concentration and presence of the
support were investigated in the reaction of ethylbenzene dehydrogenation with and without steam. For comparison, bulk catalysts were prepared with
the same conditions of coprecipitation of Fe2+
or Cu2+
ions for supported
catalysts without the use of sulfonated resin. The materials were
characterized by chemical analysis, X rays diffraction, termogravimetric
analysis and porosity measurements by nitrogen physical adsorption. It was
verified that the polymeric matrix affected the oxide type produced in
comparison with coprecipitations in solution. The supported catalysts had
better catalytic activities than the bulk and comercial ones because their
higher porosities and specfic surface areas. Besides, during the reaction,
they presented small tendence sinterization and coke formation. The last property is an intrinsic characteristic of the support based on polymeric
activated carbon.
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BARBOSA, Danns Pereira. Síntese e avaliação de óxido de ferro suportado em carvão ativado polimérico como catalisador na desidrogenação do etilbenzeno. 2007. 46 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2007.