Pd – Bi NANOPARTICLES ON ANIONIC-EXCHANGE RESINS FOR GLYCEROL OXIDATION IN
BATCH AND FIXED BED REACTOR
STANISLAV VAJÍČEK, MAGDALÉNA ŠTOLCOVÁ *, ALEXANDER KASZONYI
DEPARTMENT OF ORGANIC TECHNOLOGY, SLOVAK UNIVERSITY OF TECHNOLOGY, RADLINSKÉHO 9, 8123 47 BRATISLAVA, SLOVAKIA
Experimental
Catalyst preparation
The Dowex 1x4 anion exchanger was metallated by ion exchange method using solution of PdCl2 and BiCl3 in aqueous HCl.
The macroporous resins (Dowex66, DowexSD2) were impregnated with solution of [PdCl4]2- and [BiCl4]- in aqueous HCl for
24 h. The metallated resins were reduced with sodium borohydride dissolved in a mixture of water and isopropanol for 1 h
at laboratory temperature with occasional stirring.
Catalytic reactions
The glycerol oxidation was carried out under atmospheric pressure in a thermostated semi-batch glass reactor equipped
with a magnetic stirrer, inlet for nitrogen or oxygen and pH-meter. A jacketed tubular glass reactor heated by water and
equipped with feed lines for aqueous solution of glycerol (NaOH/glycerol=2 mol/mol) and molecular oxygen or nitrogen, an
output line cooled by water was used.
Samples were analyzed by high performance liquid chromatography on an Alltech OA-1000 column with 0.1 N aqueous
H2SO4 as eluent using a SPD 10AVp (210 nm) and RID-10A detectors.
FTIR measurements
Transmission IR spectra were recorded on Shimadzu IRAffinity FTIR Spectrometer equipped with Specac Golden Gate TM in
the range 4000-570 cm-1 at room temperature.
Introduction
In the recent years, many efforts have been made in the field of transformation the renewable resources into value added
chemicals. New starting materials, so called „platform molecules” are expected to supply fossil resources and
contribute to a sustainable chemistry [1]. Glycerol obtained from biomass represents one of the twelve platform
molecules proposed by U.S. Department of Energy [2]. Palladium, platinum and gold particles in liquid phase
oxidation of glycerol have been the subject of intensive studies. The most common supports for the metal
particles are activated carbon and graphite [1,3].
In several cases metal oxides (TiO2, CeO2 and Al2O3) were employed [4]. Recently, Prati et al. [5] have demonstrated liquid
phase oxidation of glycerol in the presence of Au species supported into macroporous resin Dowex M-43. Au
nanoparticles stabilized by tetrakishydroxypropyl-phosphonium chloride on support showed better activity than
Au particles adsorbed on Dowex M-43.
In the present work macroporous and microporous poly(styrene-co-divinylbenzene) ion exchange resins as supports for
Pd-Bi particles in liquid phase oxidation of glycerol in batch and fixed bed reactor were compared.
Results
Commercial poly(styrene-co-divinylbenzene) anion-exchange resins with different
The reactor configuration had almost no influence on the activity and
As it is shown in Figures 3 A,B and C, the spectra do not exhibit noteworthy
surface areas 7 and 800 m2/g (Dowex 1x4 and Dowex Optipore SD-2) and with varied
selectivity of the Pd-Bi NPs loaded on microporous gel type resin. In this
variations of the vibration bands for the individual supports, precursors and the
total swelling from 5 to 20% (Dowex Optipore SD-2 and Dowex 66) were used as
case, 32 % selectivity to GLYA at the conversion of glycerol more than
prepared catalysts.
support for palladium and bismuth nanoparticles (NPs). The macroporous ion-
93% was obtained at the temperature of 50°C. Decreasing the
exchange
temperature to 40°C in fixed bed reactor led to increasing the selectivity
resins
with
tertiary
ammonium
groups
were
compared
with
the
microporous gel-type resin containing quaternary ammonium groups.
of GLYA to 55% at unchanged 16.5% selectivity to TARA. Under these
Oxidation of glycerol with molecular oxygen in the liquid phase over the supported
conditions the conversion of glycerol about 85 % was reached. It implies
Pd-Bi catalysts in batch and fixed bed reactors were studied. The reactions at
that at lower temperature the consecutive oxidation of GLYA to TARA is
temperature of 50C were carried out in alkaline region adjusted by caustic soda. The
lower, the overoxidation of TARA is not so significant, moreover loss of
type of the support used strongly influenced the activity and selectivity of the
the catalyst activity expressed by glycerol conversion
catalysts in both batch and fixed bed reactors. As it is shown in Figure 1, the glycerol
substantial.
is not too
(GLY) conversion over the Pd-Bi NPs loaded on macroporous resins in batch reactor is
more than twofold higher than that in the fixed bed system. On the other hand,
Conversion, selectivity [%]
higher selectivity to glyceric acid (GLYA) and tartronic acid (TARA) formation in fixed
bed reactor was observed.
Conversion, selectivity [%]
100
80
60
40
20
100
90
80
70
60
50
40
30
20
10
0
0
0
TARA
GLYA
GLY
GLY
FB
B
B
FB
B
1
2
3
GLYA
4
TARA
5
6
7
8
9
Time on stream [h]
FB 40°C
FB 50°C
Figure 2 Catalytic performance of Pd-Bi NPs supported onto Dowex
1x4 at 40°C in fixed bed reactor
Dowex 1x4
Dowex66
SD2
Figure 1 Influence of reactor configuration (batch (B) and fixed bed (FB)) on the
activity and selectivity of the Pd-Bi nanoparticles loaded into different
supports
Acknowledgements
Figure 3 FTIR spectra of supports, precursors and prepared catalysts for
Dowex SD-2 (A), Dowex 1x4 (B) and Dowex 66 (C)
Changes in the chemical structure of used supports after the precursors
preparation and their reduction with sodium borohydride under the
chosen conditions were studied by infrared spectrometry.
This work was supported by the Slovak Research and Development Agency under the contract No.
APVV-0133-11 and ERDF under the contract No. HUSK/1101/1.2.1/0318
Conclusions
 The Pd-Bi particles supported onto commercial poly(styrene-co-divinylbenzene) gel type
strong anion-exchange resin containing quaternary ammonium groups prepared by ionexchange method showed better catalytic performance than those particles obtained by
adsorption on macroporous resins with tertiary amine groups.
References
[1]
[2]
[3]
[4]
[5]
P. Gallezot, Catal. Today, 2007, 121, 76- 86;
F. Ma, M. A. Hanna, Bioresource Technology, 1999, 70, 1-15;
L.Bianchi, N. Dimitratos, F. Porta, L. Prati, Catal. Today, 2005, 102, 212;
I. Sobczak, K. Jagodzinska, M. Ziolek, Catal. Today, 2010, 158, 121-129;
A. Villa, C. E. Chan-Thaw, L. Prati, Applied Catal. B: Environ., 2010, 96, 547.
 Activity and selectivity of Pd-Bi NPs supported onto Dowex 1x4 remained almost the same
during the 8 h of time on stream.
 No significant changes of supports were observed after the precursors and reduced catalysts
preparation in IR spectra.