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CATTOD-9851; No. of Pages11
ARTICLE IN PRESS
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A.A. Dabbawala et al. / Catalysis Today xxx (2015) xxx–xxx
hydrogenation highlighted the influence of inorganic supports as
such or their modified forms in combination with Ru metal. The
utilization of porous polymeric support to stabilized Ru nanopar-
ticles and its application in D-glucose hydrogenation is limited in
literature [40].
able commercially with different organic functionality which
possess good mechanical, thermal and chemical stability and
their applications in the field of adsorptions and catalysis
have greatly been highlighted [40–45]. Particularly, the uses
non-coordinating tertiary amine moieties (1.0–1.5 mmol N/g), non-
functionalized poly(styrene-co-divinylbenzene), 2% cross linked
polymer (PS), D-glucose, D-mannitol, D-fructose, D-sorbitol,
sodium borohydride (NaBH4) and ethanol were purchased from
M/s Sigma–Aldrich Chemicals, USA. De-ionized water is used as a
solvent. All the chemicals were used as such without further purifi-
cation. Hydrogen and nitrogen gases (99.9%) were purchased from
Deokyang Co. Ltd., Korea.
2.2. Catalyst preparation
a host
to stabilized metal/metal nanoparticles have been increased in
various organic transformations due their high specific sur-
face area, porosity and dual hydrophilic–hydrophobic character
[45–50]. The functionalized moieties in polymer enhance the
dispersion of metal and porous structures allow better diffu-
sion of reactants into the pores and facilitate interactions with
metal sites. Herein, we selected nanoporous hypercross-linked
polystyrene/divinylbenzene copolymer bearing non-coordinating
tertiary amine moieties (AFPS) and synthesized supported Ru cata-
lysts (Ru/AFPS) by impregnation and chemical reduction method
wherein ruthenium nanoparticles are dispersed on AFPS poly-
mer matrix. The AFPS polymer supported Ru nanoparticles based
catalysts were characterized using different techniques such as X-
ray powder diffraction (XRD), transmission electron microscopy
(TEM), scanning electron microscope (SEM), Fourier transform
infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), CO
chemisorptions and X-ray photoelectron spectroscopy (XPS). The
catalytic activity of synthesized Ru/AFPS catalysts was assessed first
time in the selective hydrogenation D-glucose to D-sorbitol under
aqueous phase reaction condition. The Ru nanoparticles are sta-
bilized and dispersed on AFPS matrix enhanced the formation of
desired product D-sorbitol. The various reaction parameters were
optimized in order to achieve maximum conversion of and selectiv-
ity. The catalyst Ru/AFPS could also be recycled without significant
loss in catalytic activity and selectivity.
AFPS supported ruthenium nanoparticles catalyst was prepared
by simple impregnation-chemical reduction method as reported in
the literatures [10,11]. Beads of poly(styrene-co-divinylbenzene)
amine functionalized (PSN) polymer were crushed (by ball milling)
until the fine powders were formed and then sieved to 200–300
mesh before use. To incorporate Ru (1.0% by weight) on AFPS sup-
port, 1.0 g of AFPS and RuCl3·3H2O (26 mg) were placed together
with 10 mL ethanol in a round bottom flask and attached with water
condenser and nitrogen inlet. The resulting mixture was refluxed
for a period of 12 h under an N2 atmosphere. After reflux, the reac-
tion mixture was cooled to room temperature. The Ru impregnated
AFPS was then reduced by chemical reduction method. For reduc-
tion, 0.2 M solution of NaBH4 in ethanol was added drop wise to
reaction mixture with constant stirring and entire reaction mass
formed which were stabilized by AFPS polymer matrix. Finally, cat-
alyst was separated by filtration, washed with ethanol and dried to
give dark gray AFPS supported ruthenium catalyst, 1Ru/AFPS (as
shown in Scheme 1). The catalysts having different Ru contents
such as 2Ru/AFPS, 3Ru/AFPS and 5Ru/AFPS were also prepared sim-
ilar to above described method by varying RuCl3·3H2O amount.
In the entire paper, 1Ru/AFPS, 2Ru/AFPS, 3Ru/AFPS and 5Ru/AFPS
correspond to 1, 2, 3 and 5 wt% of ruthenium content. For compari-
son purpose, 5Ru/SiO2, 5Ru/TiO2 and 5Ru/Al2O3 catalysts were also
synthesized similar to above mentioned method.
2. Experimental
2.3. Catalyst characterization and product analysis
2.1. Materials
The powder XRD of catalyst samples were carried out using
an X-ray diffractometer (MO3X-HF, Model No. 1031, CuK␣ radi-
ation). Surface area measurements of catalysts were carried out
using a surface area and porosity analyzer (Micromeritics, Tristar II
Ruthenium trichloride (RuCl3·3H2O) was purchased from
Strem Chemicals, USA. Beads (d: 300–800 m) of function-
alized poly(styrene-co-divinylbenzene) polymer (AFPS) bearing
Scheme 1. Preparation of AFPS supported ruthenium nanoparticles based catalysts with different Ru contents.
Please cite this article in press as: A.A. Dabbawala, et al., Selective hydrogenation of D-glucose using amine functionalized nanoporous