Hydrogenation of crotonaldehyde over Ir catalysts supported on titania, ceria and γ-alumina in a continuous reactor.
Keywords:
Selective hydrogenation, crotonaldehyde, titania, ceria, γ-alumina, IR catalystsAbstract
The hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols is an important step in the preparation of chemical agents useful in the pharmaceutical and food processing industries. This process is only achieved if catalysts with specific properties are used. The formation of selective surface sites on the catalyst has been shown to be crucial for the preferential C=0 hydrogenation. Previous work has studied the influence of the thermal reduction treatment of Ir catalysts supported on titania on the selective hydrogenation of the C=0 bond of crotonaldehyde in a pulse reactor. The effect of metal-support interactions has been relevant in promoting hydrogenation at the C=0 position. The study of the influence of other reducible supports such as ceria and γ-alumina on the selective hydrogenation of the C=0 bond of crotonaldehyde is a topic of interest to compare the mechanisms of electronic activation and promotion. The main objective of this work is to reveal the effect of metal-support interactions on the selective hydrogenation of the C=0 bond of crotonaldehyde over Ir catalysts supported on titania, ceria and γ-alumina in a continuous reactor. Ir catalysts supported on titania, ceria and alumina have been prepared by the incipient humidity impregnation method, dried at 100 °C for 12 h, calcined at 500 °C for 12 h and finally reduced under LTR conditions (300 °C for 2 h) and after reaction tests at 100 °C, reduced under HTR conditions (450 °C for 2 h). The influence of the reduction temperature on the catalysts supported on titania, ceria and alumina is clearly different. For the samples supported on titania, hydrogenation under HTR conditions improved the C=0 selectivity at the same conversion with respect to those treated under LTR conditions. This trend was also observed in ceria-supported samples, although to a lesser extent, but it did not affect at all the selective behaviour in γ-alumina-based samples. The results of the experiments selected in this work revealed a clear influence of the intensity of the metal-support interactions on the C=0 hydrogenation of crotonaldehyde on different metal supports, being its magnitude greater in the Ir samples supported on Ti02, followed by Ce02 and finally on γ-Al203.
Downloads
References
Bauer K., Garbe D., in Ullman Encyclopedia, VCH, New York, All, p. 141, (1988).
Rylander P., N., "Catalytic hydrogenation in Organic Synthesis", Academic Press, New York, p.72 (1979).
Shibata M.; Katawa N.; MAsumoto T. and Kimura H., J. Chem. Soc., Chem. Commun., 154-156, (1988).
Bartholomew C.H.; Pannell R.B. and Butler J.L. J. Catal. 65, 335 (1980).
Picasso G., "Ingluencia de la Temperatura de REducción de Catalizadores de Ir y Ru Soportados en Oxido de Titanio en la Hidrogenación Catalítica del Crotonaldehido", Tesis para optar el grado de Maestro de Ciencias, mención Química, UNI, Facultad de Ciencias, Lima-Perú (1999).
Mizoroki T., Seki K., Meguro S., Ozaki A., Bull. Chem. Soc. Jpn., 50, 2148 (1977).
Picasso G., Cruz S., Romero E., Monzón A., XVIII Simposio Latinoamericano de Catálisis, REsúmens, Islas Margarita (2002).
Corella J., Adanez J., Monzón A., Ind. Eng. Chem. Res., 27, 375 (1988).
Peña J. A., Monzón A., Santamaría J., J. catal. 142, 59 (1993).
Vannice M. A., Sen B. J. Catal. 115, 65 (1989).
Tauster S. J.; Fung S. C.; Garten R. L., J. Am. Chem. Soc., 100, 170 (1978),
Kaspar K., Graziani M., Picasso G., Trovarelly A., J. Molec. Catal., 72, 243 (1992).
Boaro M., Vicário M., Leitenburg C.; Dolcetti, Trovarelli A., Catal. Today 77, 407-417 (2003).
Augustine R. L., Heterogenous Catalysis in Organic Synthesis, Marcel Dekker, New York (1995).
Reyes P., Aguirre M. C., Pecchi G., Fierro J.L.G., J. Molec. Catal. A, 164, 245-251 (2000).
Trovarelli A., De Leitenburg C., Boaro M., Dolcetti G., Catal. today, 50, 353-367 (1999).
Leitenburg C., Trovarelli A., Llorea J., Cavani F., Bini G., J. Appl. Catal. A: Gen. 139, 161-173 (1996).
Somorjai G. A. in CATALYST DESIGN progress and perspectives, John Wiley and sons, (1985).
Tauster S. J. Acc. Chem. Res. 20, 389 (1987).
Abid M., Paul-Boncour V., Touroude R., Appl. Catal. A: Gen. 297, 48-59 (2006).
Abid M., Ehret G., Touroude R., Appl. Catal. A: Gen. 217, 219 (2001).
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2006 Journal of the Science Faculty @ UNI
This work is licensed under a Creative Commons Attribution 4.0 International License.
Articles published by REVCIUNI can be shared through the Creative Commons international public license: CC BY 4.0. Permissions beyond this scope can be consulted through the email revistas@uni.edu.pe
