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Synthesis and characterization of NiPdCe/γ-Al<inf>2</inf>O <inf>3</inf> catalyst for selective hydrogenation of 1,3-butadiene. Impregnation conditions study

Abstract:

In this work, we propose a method of synthesis to obtain an egg-shell type catalyst for the selective hydrogenation of 1,3-butadiene. The procedure considers the influence of acidity and temperature on the final metal distribution on the support (γ-Al2O3). Three catalysts were prepared at the same impregnation and drying conditions in order to verify the reproducibility of this technique. The co-impregnation of precursor salts was achieved by a pore-volume method in a rota-vapor device which controls temperature and velocity; the solution containing the precursor salts was put in contact with the carrier during two hours at 25 °C and pH=10. The drying was done in two stages: free moisture was dried under vacuum at 100 °C, and bound moisture at 1 atm and 150 °C in a N2 atmosphere. The solids were calcined at 400 °C during 4 hours. The catalysts were characterized by SEM-EDX, TPR and BET surface area. The surface area analysis indicates that the impregnation of metals does not considerably reduce the specific area of the original support, which is 176 m2/g. On the other hand, SEM-EDX demonstrates that the method succeeds in producing egg-shell type catalysts. Since all characterization techniques give similar results for all three sets of solids, it can be concluded that the method offers an effective and reproducible way of synthesizing eggshell catalysts. © 2011, AIDIC Servizi S.r.l.