The durability of the enantio-differentiating ability of a tartaric acid-NaBr-modified reduced nickel catalyst pre-modified in tetrahydrofuran

The enantio-differentiating hydrogenation of methyl acetoacetate was carried out over a (R,R)-tartaric acid-NaBr-modified reduced Ni catalyst. The reduced Ni was pre-modified in a tetrahydrofuran solution of tartaric acid and NaBr at atmospheric pressure or at a high hydrogen pressure. The enantio-differentiating ability of 70-90% was maintained during 40 runs over the reduced nickel catalyst pre-modified at 9 MPa hydrogen and 373 K. The results indicated that the durability of a high enantio-differentiating ability of an in-situ-modified catalyst would be attributed to the modification conditions at the high hydrogen pressure of 9 MPa and the high temperature of 373 K in the autoclave. © 2006 Springer Science+Business Media, Inc.