S. Sahin et al. / Applied Catalysis A: General 408 (2011) 137–147
147
dehydration reaction, which is catalyzed by acid sites. In order to
check a hypothesis of dehydration catalyzed by bases a separate
removal of polyvinylalcohol (PVA), used during catalyst prepara-
tion.
with basic sites/CO2 uptake 292 mol/g and BET equal 57 m2 g−1
)
Acknowledgements
resulting in the absence of any dehydration.
As mentioned above a decrease in the initial hydrogenation rates
was observed with more complete catalyst reduction. Based on
Figs. 13–15 it could be stated that such decrease was associated
with higher initial selectivity to the desired product and much
lower rates of ethylbenzene formation. Among various possible
explanations for this behavior, metal oxidation state, resistance to
deactivation, structure sensitivity and influence of PVA could be
mentioned. Most probably differences in metal dispersion as well as
catalyst stability cannot be responsible for substantial differences
in catalytic performance, which could be tentatively attributed to
partial removal of PVA during post catalyst synthesis reduction
with hydrogen leading to additional metal reduction.
The maximum yield of (R)-1-phenylethyl acetate over Entry
2.0 was 35% at 98% conversion of acetophenone corresponding
to 36% selectivity over 312.5 mg of Pd-catalyst in combination
improved by using Pd-N-VGCF catalysts comparing to the yields
obtained with Pd on active carbon as the maximal yield reported
for the latter catalyst was 15% at 66% conversion of acetophenone
[35]. In addition for one pot reaction with Pd on active carbon the
major product was ethyl benzene due to the acidic character of the
support.
This work is part of the activities at the Åbo Akademi Process
Chemistry Centre within the Finnish Centre of Excellence Pro-
gramme (2000–2011) by the Academy of Finland.
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