Catalisadores de cobre suportados em óxidos de zircônio hierarquicamente estruturados para a reação de desidrogenação de etanol

• Ano de defesa: 2014
• Autor(a) principal: Schiavon, João Victor [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Cobre; Oxido de zirconio; Catalise; Etanol; Processo sol-gel; Ethanol
• Link de acesso: http://hdl.handle.net/11449/124421; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/16-06-2015/000827093.pdf

In this work, we investigated the activity and selectivity of copper catalysts supported on zirconium oxide, obtained by different preparation methods, in the ethanol dehydrogenation reaction. From the ethanol, the most important products are ethyl acetate and acetaldehyde, because they have high valuable and are in the spotlight in the alcohol transformations that takes place in the supported copper catalysts. Papers from literature about copper catalysts and zirconium oxide have shown great potential in the increase of selectivity to ethyl acetate. This fact motivates the investigation of new modifications in the catalyst/support system in order to improve the reaction and get more information about the mechanism involved in the catalytic reaction. The supported zirconium oxide was made through the sol-gel methodology to achieve ceramic foam with controlled hierarchical porosity using specific surfactant. Posteriorly, copper catalysts were by wetness impregnation of the support. The supports and catalysts were characterized by their chemical composition, structure, morphology, surface and catalytic activity with the application of experimental technics of mercury porosimetry, nitrogen physisorption, thermogravimetry and X-rays diffraction that helped in the understanding and evaluation of the catalysts performance. The results demonstrated that the porous zirconium oxide benefits the dispersion of the copper catalyst improving the reagents and products diffusion on ethanol stream, making better the reaction kinetics. Is important to apply attention to the zirconium oxide calcination temperature in reason of the sulphate groups removal of the porous structure, once that those groups generate acid sites that interfere in the ethanol dehydrogenation reaction in theirs predilection for dehydration reactions.