Received: September 29, 2017 | Accepted: October 19, 2017 | Web Released: December 15, 2017
CL-170920
Hydrogenolysis of Tetrahydrofurfuryl Alcohol to 1,5-Pentanediol
over a Nickel-Yttrium Oxide Catalyst Containing Ruthenium
Husni Wahyu Wijaya,1,2 Takayoshi Hara,1 Nobuyuki Ichikuni,1 and Shogo Shimazu*1
1Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University,
1-33 Yayoi, Inage, Chiba 263-8522, Japan
2Department of Chemistry, Faculty of Mathematics and Sciences, Universitas Negeri Malang (State University of Malang),
Jl. Semarang 5 Malang, 65145 Indonesia
E-mail: shimazu@faculty.chiba-u.jp
A Ni-Y2O3 catalyst containing ruthenium (Ru/Ni-Y2O3)
was synthesized and applied to the hydrogenolysis of tetrahy-
drofurfuryl alcohol (THFA) to produce 1,5-pentanediol (1,5-
PeD), which showed superior catalytic performance over that of
the Ni-Y2O3 catalyst itself. The optimized ruthenium-containing
catalyst, which was prepared by impregnation of 1.0 wt %
ruthenium in Ni-Y2O3, showed high catalytic activity for
producing 1,5-PeD, giving an 86.5% yield at 93.4% conversion
of THFA under 2.0 MPa of H2 at 423 K after 40 h. The formation
of Ru-Ni0-Y2O3 boundaries was proposed to accelerate the C-O
bond scission of the tetrahydrofuran ring to give 1,5-PeD.
scission,11 and the Ru-Ni bimetallic catalyst is known to be
highly active for hydrogenation;12-15 however, their combination
could enhance the C-O bond cleavage of the THFA ring, giving
1,5-PeD rather than 1,2-pentanediol. We expect that modifica-
tion of Ni-Y2O3 with ruthenium could accelerate hydride
formation on the catalyst surface to then attack the C-O bond
of the tetrahydrofuran ring, i.e., the Ru-Ni0-Y2O3 boundaries
could facilitate C-O bond cleavage.
The Ni-Y2O3 material containing a ruthenium catalyst was
prepared by impregnating ruthenium chloride in NiO-Y2O3 and
subsequent hydrogen treatment at 673 K before the catalytic
reaction was performed. The catalyst was denoted n Ru/Ni-
Y2O3, where n = wt % (weight %) of Ru feeding amount. All
catalysts were characterized by powder X-ray diffraction, FTIR
observation, and hydrogen uptake. The details of the catalyst
preparation, catalysis experiments, and analysis of the products
are described in the Supporting Information.
Keywords: Hydrogenolysis
| 1,5-Pentanediol |
Ruthenium-nickel-yttrium oxide catalyst
Recently, a multistep catalytic conversion from a furfural
feedstock to 1,5-pentanediol (1,5-PeD) involving hydrogenation
and dehydration-hydration-hydrogenation processes was mod-
elled from a technoeconomic analysis point of view.1 The
authors suggested that the transformation of tetrahydrofurfuryl
alcohol (THFA) through 2-hydroxytetrahydropyran formation
previously obtained from dehydration (γ-Al2O3 catalyst) and
hydration processes is a preferable route, giving 1,5-PeD in up
to 80% for overall yield from furfural.1,2 Schniepp and Geller
pioneered that reaction using activated alumina and then copper
chromite.3 Modified noble metal catalysts, especially Rh-ReOx/
C, have demonstrated the best results, with 1,5-PeD yields up to
94.2% from THFA.4-6 The Brønsted acidic metal oxide
modifiers ReOx and MoOx are essential to binding the oxygen
atoms (ether and hydroxy groups) of THFA and breaking a C-O
bond to give the pentanediol products.7,8 The recent update in
this reaction resulted in 1,5-PeD with up to 35% yield using
5%Pt/WO3/ZrO2 catalyst which elaborated the role of reducible
WOx as an acidic site.9 To modify the Ni catalyst while
preserving hydrogen molecule dissociation, our group has
successfully added yttrium or lanthanum to facilitate the scission
of the C-O bond, giving 1,5-PeD from furfural (FFR), furfuryl
alcohol (FFA), and THFA.10,11 Encouraged by this result, the
improvement of the Ni-Y2O3 catalyst is an important approach
to accelerating the selective C-O bond cleavage of the
tetrahydrofuran ring to give 1,5-PeD. To achieve that goal, the
exploration for the addition of relatively economical noble metal
such as ruthenium into the Ni-Y2O3 catalyst has been evaluated
in this study. Although the hydrogenolysis of THFA to 1,5-PeD
is mostly catalyzed employing noble metal-based catalysts, our
nickel-based catalyst showed comparable catalytic performance
according to the results described in the manuscript. The
boundary of Ni0-Y2O3 is known to be responsible for C-O bond
The FTIR spectra of the catalysts exhibited similar
absorption bands, as shown in Figure S1. The presence of
hydroxy groups on the surface of the Ni-Y2O3 and Ru-
containing catalysts were assigned as OH stretching (broad
peak 3400 cm¹1), OH bending (1630, 1508, and 1384 cm¹1),
¹1
Y-OH bending (800 cm¹1), and Y-O vibration (600-300 cm
)
bands.16,17 Moreover, the Y-O vibration mode shifted to lower
wavenumbers (464 to 458 cm¹1) in all the Ru-containing
catalysts. Thermogravimetric analysis of the 1.0Ru/Ni-Y2O3
catalyst under an N2 flow showed a mass loss below 473 K of
only approximately 3.3% (Figure S2), which could be assigned
to a dehydration process. This result indicates that Ru was
highly dispersed and had weak interactions with Y2O3.
The addition of Ru into the Ni-Y2O3 catalyst was success-
fully accomplished by an impregnation method and subsequent
H2 treatment at 673 K. The XRD patterns of the Ru-containing
catalysts with various amounts of Ru are shown in Figure 1.
Diffraction peaks from Ni metal (2ª = 44.4, 51.7, and 76.3)
were observed in all the Ru-containing samples. Meanwhile, the
diffraction peaks of Ru species were not detected owing to the
low content (¯5 wt %) and high dispersion of Ru. The hydrogen
treatment at 673 K was necessary to form zero valent Ni and
Ru.18,19 The peaks from Ni metal were sharp in the samples
containing 3.0-5.0 wt % ruthenium, indicating the agglomera-
tion of Ru-Ni bimetallic species.20 The strongest diffraction
peaks at approximately 44° for both Ni(111) and Ru(101) are
very close and are superimposed in the bimetallic systems
because the metals crystallize with a similar structure, and they
have fairly similar ionic radii (Ni: 1.25 ¡ and Ru: 1.34 ¡).21
The intensity of the easily observed Y2O3 diffraction peak at
2ª = 29.2° decreased with increasing Ru content. This change
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