II International Symposium on Carbon for Catalysis ABSTRACTS

OP-I-9
FABRICS OF ACTIVE CARBON FIBERS WITH Pd-NANOPARTICLES OF
CONTROLLED DISPERSION FOR SELECTIVE 1-HEXYNE HYDROGENATION
Semagina N., Renken A., Kiwi-Minsker L.
LGRC-ISIC, Ecole polytechnique fédérale de Lausanne (EPFL), Switzerland
e-mail: natalia.semagina@epfl.ch
Catalytic hydrogenation is one of the key processes for manufacturing pharmaceuticals,
vitamins and fine chemicals. The performance of the hydrogenation process and product
distribution is strongly influenced by the catalyst activity and selectivity, the interaction of
chemical kinetics and mass transfer, as well as the reactor design. Process intensification and
integrated environmental protection can be improved by multiple catalyst reuses. To avoid
internal and external mass transfer limitations and to attain high product selectivity catalyst
particles of small diameter are required. In technical applications the minimal size, however,
is limited due to the catalyst filtration after the reaction.
One novel approach to overcome these problems is the use of filamentous catalytic
materials like woven cloths for the deposition of active components. The diameters of the
filaments are in the order of several micrometers and correspond to the diameter of the
traditional suspension catalysts. Therefore, the influence of internal mass transfer on overall
kinetics could be suppressed.
Another problem of the catalyst design is related to the size control of the active metal
nanoparticles and the size distribution. Traditional preparation by impregnation/ion-exchange
gives broad distribution affecting activity/selectivity in the structure-sensitive reactions. The
aim of this work was the development of Pd catalyst with monodispersed metal nanoparticles
(~8 nm) deposited on active carbon fiber (ACF) fabrics efficient in selective liquid-phase
alkyne hydrogenation.
Experimental
The catalyst preparation consists of a formation of Pd-nanoparticles of the controlled size
in a reverse microemulsion, evaporation of liquid phases, surfactant removal by dissolution in
methanol, ultrasound-assisted redispersion of flocculated nanoparticles in water and ACF
impregnation. This method allows obtaining catalysts with high metal loading, retaining the
nanoparticles monodispersity by avoiding calcination steps and recovering liquid phases of
microemulsion and a part of a surfactant.
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