Abstract
Pt/γ-Al2O3 catalysts were prepared by two different impregnation methods and characterized by XRD, TEM, and CO chemisorption. The Pt particle sizes ranged in 2.4–23.3 nm for these 5.0 wt% Pt/γ-Al2O3 catalysts. The catalysts were also characterized by FT-IR spectroscopy using CO as a probe molecule before and after the chiral modification with cinchonidine. Two IR bands (2078 and 2060 cm-1) due to CO linearly adsorbed on the Pt/γ-Al2O3 catalyst, calcined at 500 °C before reduction in sodium formate solution were observed, whereas only one IR band at ∼2070 cm-1 was observed for other catalysts. A red shift of the IR band was observed after chiral modification of all the catalysts, except the one with the largest Pt particle size and lowest Pt dispersion. The catalytic performance of the cinchonidine-modified Pt/γ-Al2O3 catalysts was tested for the enantioselective hydrogenations of ethyl pyruvate and ethyl 2-oxo-4-phenylbutyrate (EOPB). A 95% ee value was obtained for the ethyl pyruvate hydrogenation and about 83% ee was achieved for the enantioselective hydrogenation of EOPB under the optimized preparation and reaction conditions. It is deduced that the interaction of Pt with γ-Al2O3 is a crucial factor for obtaining high activity and that the adsorption abilities (adsorption of reactant, solvent and chiral modifier molecules) of the catalyst surface affect the catalytic performance significantly.
Similar content being viewed by others
References
H. Yamada, Catal. Lett. 67 (2000) 61.
Y. Orito, S. Imai and S. Niwa, Preprints of the 43rd Catalysis Forum (Japan, 1978) p. 130; Y. Orito, auS. Imai and S. Niwa, J. Chem. Soc. Jpn. (1979) 1118; Y. Orito, S. Imai and S. Niwa, J. Chem. Soc. Jpn. (1980) 670; Y. Orito, S. Imai and S. Niwa, J. Chem. Soc. Jpn. (1982) 137.
H.U. Blaser, H.P. Jalett, M. Muller and M. Studer, Catal. Today 37 (1997) 441, and References cited therein.
H.U. Blaser, Tetrahedron: Asymmetry 2 (1991) 843.
A. Baiker, J. Mol. Catal. A: Chem. 115 (1997) 473.
A. Baiker, J. Mol. Catal. A: Chem. 163 (2000) 205.
M. Studer, H.U. Blaser and C. Exnerb, Adv. Synth. Catal. 345 (2003) 45, and References cited therein.
H.U. Blaser, H.P. Jalett, W. Lottenbach and M. Studer, J. Am. Chem. Soc. 122 (2000) 12675.
S.P. Griffiths, P. Johnston and P.B. Wells, Appl. Catal. A: Gen. 191 (2000) 193.
X. Zuo, H. Liu, D. Guo and X. Yang, Tetrahedron 55 (1999) 7787.
T.J. Hall, J.E. Halder, G.J. Hutchings, R.L. Jenkins, P. Johnston, P. McMorn, P.B. Wells and R.P.K. Wells, Top. Catal. 11/12 (2000) 351.
K. Balazsik, B. Torok, G. Szakonyi and M. Bartok, Appl. Catal. A: Gen. 182 (1999) 53.
U. Bohmer, F. Franke, K. Morgenschweis, T. Bieber and W. Reschetilowski, Catal. Today 60 (2000) 167.
J.T. Wehrli, A. Baiker, D.M. Monti and H.U. Blaser, J. Mol. Catal. 61 (1990) 207.
X. Li, Y. Xin, C. Liang, S. Zhang, Z. Wei, X. Li and C. Li, Chem. J. Chin. Univ. 21 (2000) 1900.
X. Li and C. Li, Catal. Lett. 77 (2001) 251.
X. You, X. Li, S. Xiang, S. Zhang, Q. Xin, X. Li and C. Li, Stud. Surf. Sci. Catal. 130(D) (2000) 3375.
Y. Wang, J. Ren, K. Wang, L. Gui and Y. Tang, Chem. Mater. 12 (2000) 1622.
O. Dulaurent and D. Bianchi, Appl. Catal. A: Gen. 196 (2000) 271.
M.V. Arx, T. Burgi, T. Mallat and A. Baiker, Chem. Eur. J. 8 (2002) 1430.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Li, X., You, X., Ying, P. et al. Some Insights into the Preparation of Pt/γ-Al2O3 Catalysts for the Enantioselective Hydrogenation of α-Ketoesters. Topics in Catalysis 25, 63–70 (2003). https://doi.org/10.1023/B:TOCA.0000003098.58993.cd
Issue Date:
DOI: https://doi.org/10.1023/B:TOCA.0000003098.58993.cd