Comportamento de catalisadores Rh-Sn e Pt-Fe suportados por silica e titania na reação de hidrogenação do citral

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

This work intends to verify which is the most efficient system in the hydrogenation of citral to unsaturated alcohols: Pt-Fe/Ti O IND. 2 , Rh-Sn/Si O IND. 2 . Catalysts having 1% of Rh and Sn/Rh = 0,92 (at/at), 4,7% of Pt and 0,3% of Fe were prepared by the wet impregnation from chlorated precursors solutions, thereafter they were dryed. Rh-Sn/Ti O IND. 2 was submitted to a three different treatments: a fraction of these materials was directly reduced at low temperature ( 250 GRAUS C/4h) and other at high temperature ( 400 GRAUS C/4h); another fraction was earlier submitted to a calcinations treatment ( 500 GRAUS C/3h) prior to reduction ( 400 GRAUS C/1h). Rh-Sn/Si O IND. 2 was directly reduced at 400 GRAUS C/4h and the Pt-Fe/Ti O IND. 2 catalysts was reduced at two different temperatures: 190 GRAUS C/4h and 400 GRAUS C/4h. The characterization techniques used in this study were: Termogravimetric Analysis, Temperature Programmed Reduction, Mossbauer Spectroscopy, H IND. 2 Chemisorption and H IND. 2 - O IND. 2 Titration. The reactions of hidrogenation of citral were realized to 50 bar of H IND. 2 and 126 GRAUS C with stirring speed of 1500 r.p.m. the addition of promoters (Sn and Fe) leads to increments of selectivity to unsaturated alcohols, geraniol and nerol, taking account that the formation of saturated aldehyde (citronellal) is preferential in the presence of rhodium monometallic supported catalysts... Note: The complete abstract is available with the full electronic digital thesis or dissertations.

ASSUNTO(S)

estanho dioxido de titanio espectroscopia de mossbauer aldeidos rodio silica hidrogenação

ACESSO AO ARTIGO

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