Resumo

ROJAS SARMIENTO, Hugo Alfonso; MARTINEZ ZAMBRANO, José Jobanny  e  REYES, Patricio Alberto. Kinetic study of the hydrogenation of trans-cinnamaldehyde over Ir/Nb₂O₅ catalysts. Rev.fac.ing.univ. Antioquia [online]. 2010, n.55, pp.9-17. ISSN 0120-6230.

The hydrogenation of trans-cinnamaldehyde was studied over Ir/Nb₂O₅ catalysts reduced at 473 K (LTR) and 773 K (HTR). The catalysts were characterized by N₂ physisorption at 77 K, H₂ chemisorption, TPR, and TPD- NH₃. Kinetic study of trans-cinnamaldehyde over Ir/Nb₂O₅ reduced at HTR was carried out in n-heptane at hydrogen pressures in the range of 0.48 to 0.98 MPa, the reaction temperatures were 323-363 K, catalyst loadings 0.1 to 0.3 g and cinnamaldehyde concentrations 0.025 to 0.1 M. Trans-cinnamaldehyde can be selectively hydrogenated to cinnamyl alcohol although the support acidity leads to the formation of byproducts. A Langmuir-Hinshelwood model with molecular adsorption of hydrogen non competitive with organic molecules and considering the surface reaction as the rate-controlling step provided the best fit of the experimental data.

Palavras-chave : Nb₂O₅; hydrogenation; trans-cinnamaldehyde; SMSI effect; Langmuir-Hinshelwood.

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