E. Toukoniitty et al., Batchwise and continuous enantioselective hydrogenation of 1-phenyl-1,2-propanedione catalyzed by new Pt/SiO2 fibers, APP CATAL A, 216(1-2), 2001, pp. 73-83
A new knitted silica fiber was investigated as a support material in enanti
oselective hydrogenation of 1-phenyl-1,2-propanedione in a pressurized batc
h reactor. The active metal was platinum and the catalyst was modified in s
itu with (-)-cinchonidine. The catalysts were prepared by impregnation meth
od using hexachloroplatinic acid as metal precursor. The main experimental
parameters were the support calcination temperature and the metal loading o
f the catalyst. The optimum catalyst dispersion, BET specific surface area
and mean Pt particle size for enantio-differentiation were measured. A comp
arison of alumina and silica supports revealed that the main parameters in
the enantio-differentiation were the mean metal particle size and the metal
dispersion. Optimal metal particle size and dispersion were detected which
optimize the enantioselection. Experiments with continuously operated fixe
d bed reactor demonstrated that continuous hydrogenation, over the new knit
ted silica fiber catalyst, gives equally high enantiomeric excesses compare
d to the batch operation. Continuous operation can be used as tool to study
catalyst deactivation and reaction mechanisms in enantioselective hydrogen
ation. (C) 2001 Elsevier Science B.V. All rights reserved.