Restructuring during pretreatment of platinum/alumina for enantioselective hydrogenation
作者： T. Mallat , S. Frauchiger , P.J. Kooyman , M. Schürch , A. Baiker
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摘要: The influence of reductive and oxidative heat treatment on the enantioselectivity chirally modified Pt/alumina has been reinvestigated, using hydrogenation ketopantolactone as a test reaction. Enhancement in ee by 39–49% observed after hydrogen at 250–600°C, compared to untreated or preoxidized catalysts. changes treatments are reversible, always final is decisive. A HRTEM study indicates that adsorbate‐induced restructuring Pt crystallites during elevated temperature can play role selectivity improvement, but superimposed strong structure‐directing effect alumina support. possible contribution other effects (complete reduction Ptn+ surface species, removal impurities, change particle size) could be excluded.
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H.U. Blaser, H.P. Jalett, D.M. Monti, J.F. Reber, J.T. Wehrli, Modified Heterogeneous Platinum Catalysts for the Enantioselective Hydroge-Nation of α-Ketoesters Studies in Surface Science and Catalysis. ,vol. 41, pp. 153- 163 ,(1988) , 10.1016/S0167-2991(09)60810-7
T. Mallat, M. Bodmer, A. Baiker, Enantioselective hydrogenation of trifluoroacetophenone over cinchonidine-modified platinum Catalysis Letters. ,vol. 44, pp. 95- 99 ,(1997) , 10.1023/A:1018983832315
M. Bartók, Stereochemistry of heterogeneous metal catalysis ,(1985)
Alfons Baiker, Progress in asymmetric heterogeneous catalysis: Design of novel chirally modified platinum metal catalysts1Communication presented at the First Francqui Colloquium, Brussels, 19–20 February 1996.1 Journal of Molecular Catalysis A: Chemical. ,vol. 115, pp. 473- 493 ,(1997) , 10.1016/S1381-1169(96)00352-4
G.A. Somorjai, G. Rupprechter, Molecular Studies of the Mobility of Surface Metal Atoms and Adsorbates During Catalytic Reactions Studies in Surface Science and Catalysis. ,vol. 109, pp. 35- 59 ,(1997) , 10.1016/S0167-2991(97)80397-7
A.-C. Shi, R.I. Masel, The effects of gas adsorption on particle shapes in supported platinum catalysts Journal of Catalysis. ,vol. 120, pp. 421- 431 ,(1989) , 10.1016/0021-9517(89)90282-0
P MEHEUX, Enantioselective hydrogenation: II. variation of activity and optical yield with experimental variables in methyl pyruvate hydrogenation catalyzed by cinchona-modified platinum/silica (EUROPT-1) Journal of Catalysis. ,vol. 128, pp. 387- 396 ,(1991) , 10.1016/0021-9517(91)90297-H
R. Whyman, S.D. Jackson, J. Willis, G.D. Mclellan, G. Webb, M.B.T. Keegan, R.B. Moyes, S. Simpson, P.B. Wells, Supported Metal Catalysts: Preparation, Characterization, and Function: I. Preparation and Physical Characterization of Platinum Catalysts Journal of Catalysis. ,vol. 139, pp. 191- 206 ,(1993) , 10.1006/JCAT.1993.1017
T. Wang, C. Lee, L.D. Schmidt, Shape and orientation of supported Pt particles Surface Science. ,vol. 163, pp. 181- 197 ,(1985) , 10.1016/0039-6028(85)90857-X
Anita S. Ramachandran, Shane L. Anderson, Abhaya K. Datye, The effect of adsorbate and pretreatment on the shape and reactivity of silica-supported platinum particles Ultramicroscopy. ,vol. 51, pp. 282- 297 ,(1993) , 10.1016/0304-3991(93)90154-P