4th EucheMs chemistry congress

Poster Session 2
s1197
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - solid state chemistry
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hiGhLy diSPerSed CuCo (Bi)MetALLiC
CAtALyStS PrePAred By
dePoSition-PreCiPitAtion on MeSoPorouS
SBA-15 SuPPort for the CinnAMALdehyde
hydroGenAtion
B. drAGoi 1 , A. unGureAnu 1 , A. ChirieAC 1 ,
C. CiotoneA 1 , S. royer 2 , d. duPrez 2 ,
e. duMitriu 1
1 “Gheorghe Asachi” Technical University of Iasi, Organic
Biochemical and Food Engineering Department, Iasi,
Romania
2 Université de Poitiers, LACCO UMR 6503 CNRS, Poitiers,
France
Highly dispersed copper-cobalt nanoparticles with 5 wt %
metal loading and Cu:Co weight ratio of 4:1 were prepared by
deposition-precipitation (DP), using urea as precipitating agent,
into the channels of a mesoporous SBA-15 support. The
monometallic Cu/ and Co/SBA-15 (5 wt. %) were also prepared
by DP and used as references. The resulted materials either asmade
or calcined were characterized in relation to their chemical,
structural, textural and reducible properties by chemical analysis,
XRD, N physisorption, TEM/EDX, FT-IR spectroscopy, ATG and
2
TPR. The catalytic performance of the copper-cobalt containing
materials was evaluated in the hydrogenation of cinnamaladehyde
(CNA) in liquid phase. The high-angle XRD patterns of
mono- and bimetallic catalysts besides FT-IR spectra and ATG
curves indicate the formation of phyllosilicates with very high
dispersion and thermal stability as precursors of the metallic active
phases. Moreover, the TPR analysis displayed reduction
temperatures very close to those corresponding to phyllosilicates.
However, the synthesis of such materials by DP led to partial
alteration of the support mesostructure, which was shown by
nitrogen physisorption and TEM. The EDX analysis carried out
in various points of the catalysts shows a homogeneous
distribution of the metal precursors at micrometric scale.
Generally, the catalytic activity of the monometallic catalysts is
in line with the characterization results. Therefore, for
Cu/SBA-15, the very high dispersion of Cu0 precursor generate
an active (conversion of CNA = 40 mole % after 360 min of
reaction) and selective catalyst for cinamyl alcohol (CNOL,
40 mole % at iso-conversion of 40 mole %). Due to their hardly
reducible cobalt precursors, the cobalt based catalysts were less
performing in the hydrogenation of CNA. However, the
Co/SBA-15 displayed improved selectivity to CNOL (50 mole %
at iso-conversion of 18 mole %).
Acknowledgement: The authors acknowledge the project PNII-
Idei No.264/2011 financed by UEFISCDI.
Keywords: metal supported catalysts; copper; cobalt;
cinnamadehyde hydrogenation;
4 th EucheMs chemistry congress
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MiLd dryinG iMPreGnAtion Method uSed for
the PrePArAtion of MeSoStruCtured
CAtALytiC MAteriALS ContAininG Cu, ni And
Co AS ACtive PhASeS in the hydroGenAtion
of CinnAMALdehyde
e. duMitriu 1 , B. drAGoi 1 , A. unGureAnu 1 ,
A. ChirieAC 1 , C. CiotoneA 1 , S. royer 2 , d. duPrez 2
1 “Gheorghe Asachi” Technical University of Iasi, Organic
Biochemical and Food Engineering, Iasi, Romania
2 Université de Poitiers, LACCO UMR 6503 CNRS, Poitiers,
France
This study deals with the preparation of monometallic
catalysts by an upgraded version of the conventional wetness
impregnation method, named mild drying impregnation (MDI).
Therefore, Cu, Co and Ni monometallic catalysts with 5 wt %
metal loading on support were prepared by MDI on SBA-15,
followed by calcination, reduction and then by characterization
and testing in the hydrogenation of cinnamaldehyde (CNA) to
obtain cinnamylalcohol (CNOL). For a good dispersion of the
metal precursors, all impregnated samples were subjected to
drying for two weeks at controlled temperature. All samples were
preliminary characterized by XRD at high and low angles,
nitrogen physisorption, TPR, FT-IR and ICP-OES. High angles
XRD patterns mainly reveals the formation of the corresponding
oxides and, in a less extent, of the (phyllo)silicates for all
monometallic samples. The (phyllo)silicates are responsible for
the dispersion and stabilization of the resulted metallic active
phases but also for the high reduction temperatures as observed
in TPR curves. The TPR profiles display two maxima, the first
one corresponding to the reduction of the metallic cation from
oxides while the second one is attributed to the reduction of
cations from (phyllo)silicates. The textural properties of the
calcined catalysts are similar to those of the mesoporous SBA-15
support showing a narrow pore size distribution of the cylindrical
pores. A new porous system is observed for Ni/ and Co/SBA-15
samples. The catalytic evaluation of the monometallic samples
revealed a very active Ni/SBA-15 catalyst but less selective for
CNOL. Co/SBA-15 converted only 18 mole % of CNA in
360 min of reaction but the selectivity to CNOL was much
improved (60 mole % at X =20 mole %). Cu/SBA-15 displayed
CNA
no activity in the CNA hydrogenation.
Acknowledgement: PNII-Idei, 264/2011 financed by
UEFISCDI.
Keywords: mild drying impregnation; metal supported
catalysts; hydrogenation; cinnamaldehyde;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc