C-O bond hydrogenolysis of cyclic ethers with OH groups over rhenium-modified supported iridium catalysts

Article abstract of DOI:10.1016/j.jcat.2012.07.015

Hydrogenolysis of tetrahydrofurfuryl alcohol to 1,5-pentanediol and other related substrates such as 3-hydroxytetrahydrofuran and 1,2-cyclohexanediol proceeds over Ir-ReO_x/SiO₂ catalyst. TOF values are higher than those of Rh-ReO_x/SiO₂, which has been reported to be an effective catalyst. The selectivity to the product, where the C-O bond neighboring the C-OH group in the substrate is dissociated, is comparable to or higher than that of Rh-ReO_x/SiO₂. Hydrogenolysis of most substrates except 1,2-cyclohexanediol proceeds via the direct mechanism where hydride species formed from hydrogen molecule attacks the anti-position of C-O bond. In the case of hydrogenolysis of 1,2-cyclohexanediol where attack of anti-position of C-O bond is unfavorable, indirect mechanism involving dehydrogenation to 2-hydroxycyclohexanone is responsible for the formation of cyclohexanol.

Full text of DOI:10.1016/j.jcat.2012.07.015

Supporting information
C-O bond hydrogenolysis of cyclic ethers with OH groups over rhenium-modified supported
iridium catalysts
Kaiyou Chena, Kazuma Moria, Hideo Watanabeb, Yoshinao Nakagawaa, Keiichi Tomishigea*
aDepartment of Applied Chemistry, School of Engineering, Tohoku University
6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
bGraduate School of Pure and Applied Sciences, University of Tsukuba,
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
*Corresponding author
Keiichi Tomishige
Department of Applied Chemistry, School of Engineering, Tohoku University
6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
Tel&Fax: +81-22-795-7214
E-mail: tomi@erec.che.tohoku.ac.jp

1. Details of the XRD observation
X-ray diffraction (XRD) patterns of Ir/SiO2 and Ir-ReOx/SiO2 after the hydrogenolysis of
tetrahydrofurfuryl alcohol were recorded with Rigaku Ultima IV using Cu Kα (λ = 0.154 nm)
generated at 40 kV and 20 mA (Figure S1). Average metal particle size was estimated using the
Scherrer equation [S1]. The peak around 2θ = 40.5° is assigned to Ir metal. The average size of Ir
metal particles on Ir/SiO2 was estimated to be 3.9 nm ± 0.3 nm from the linewidth of the peak. The
peak position of Ir-ReOx/SiO2 after the hydrogenolysis of tetrahydrofurfuryl alcohol was 2θ≈41°,
which was almost the same as that on Ir/SiO2. No peak shift on various Re amount suggests the
formation of Ir metal phase on Ir-ReOx/SiO2 catalysts. On the other hand, the presence of Re
affected the peak width. These results indicate that the average metal particle size of Ir decreased
with increasing the Re amount as listed in Figure S1. The XRD patterns and particle sizes are
almost the same as those of Ir-ReOx/SiO2 after the hydrogenolysis of glycerol [S2].
●
Ir particle size / nm
f: 1.5
1160
580
0
●SiO2
○Ir
○
f
e: 1.5
e
d
c
b
d: 1.9
c: 2.1
b: 2.4
a: 3.9
○
a
10
20
30
40
2θ / °
50
60
70
Figure S1. XRD patterns of the catalysts after the hydrogenolysis of tetrahydrofurfuryl alcohol.
Ir/SiO2 (a) and Ir-ReOx/SiO2 (Re/Ir=0.25 (b), 0.5 (c), 1 (d), 2 (e), 3 (f))
2. Reaction kinetics of related substrates hydrogenolysis over Ir-ReOx/SiO2 and Rh-ReOx/SiO2
Figure S2 shows the log-log plot of the substrate conversion rate and the formation rate of the
products against H2 pressure or substrates concentration on the basis of the data listed in Tables 4-6.
The obtained reaction orders are listed in Table 7.

a)
b)
1.6
1.2
0.8
0.4
0.0
1.6
1.2
0.8
0.4
0.0
THFA to 1,5-PeD
(Table 3, entries 5-12)
THFA to 1,5-PeD
(Table 3, entries 1-4)
0.0
0.4
0.8
1.2
1.6
0.0
0.4
0.8
1.2
1.6
Log (H2 pressure/ MPa)
Log (THFA concentration / %)
1.5
1.1
0.7
0.3
d)
c)
3-HTHF to 1,3-BuD
(Table 4, entries 3-5, 8-10)
1.0
0.6
0.2
3-HTHF to 1,3-BuD
(Table 4, entries 1-3, 6-8)
-0.1
-0.5
-0.9
-0.2
-0.6
-0.9 -0.5 -0.1 0.3 0.7 1.1 1.5
Log (3-HTHF concentration / %)
-0.6 -0.2 0.2
0.6
1.0
Log (H2 pressure/ MPa)
1.2
0.8
0.4
0.0
-0.4
e)
f)
Cis-1,2-CHD to c-HxOH
(Table 4, entries 1, 5-6, 12-14)
1.3
0.9
0.5
0.1
-0.3
Cis-1,2-CHD to c-HxOH
(Table 5, entries 1-4, 8-11)
-0.4
0.0
0.4
0.8
1.2
-0.3
0.1
0.5
0.9
1.3
Log (Cis-1,2-CHD concentration / %)
Log (H2 pressure/ MPa)
g)
h)
0.9
0.5
0.1
1.4
Trans-1,2-CHD to c-HxOH
(Table 4, entries 1, 5-6, 12-14)
1.0
0.6
Trans-1,2-CHD to c-HxOH
(Table 5, entries 1-4, 8-11)
0.2
-0.3
-0.7
-0.2
-0.6
-0.7 -0.3
0.1
0.5
0.9
-0.6 -0.2 0.2 0.6 1.0 1.4
Log (H2 pressure/ MPa)
Log (Trans-1,2-CHD concentration / %)
Figure S2. Log-log plot of the kinectics data over Ir-ReOx/SiO2 (Re/Ir=2) and Rh-ReOx/SiO2 (Re/Rh=0.5).
■, substrate conversion rate over Ir-ReOx/SiO2 (Re/Ir=2); □, product formation rate over Ir-ReOx/SiO2
(Re/Ir=2);
▲, substrate conversion rate over Rh-ReOx/SiO2 (Re/Rh=0.5); Δ, product formation rate over Rh-ReOx/SiO2
(Re/Rh=0.5).
3

3. Details of the X-ray absorption spectroscopic analysis
The extended X-ray absorption fine structure (EXAFS) spectra were measured at the BL01B1
station at SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI;
Proposal No 2011B1095). The storage ring was operated at 8.0 GeV. A Si (111) single crystal was
used to obtain a monochromatic X-ray beam. Measurements were carried out in a similar way to the
reference [S2]. For the curve fitting analysis, the empirical phase shift and the amplitude function
for the Re-O and Ir-Ir bonds were extracted from data for NH4ReO4 and Ir metal, respectively.
Theoretical functions for the Re-Ir bond were calculated using the FEFF8.2 program [S3]. The
Re-Ir and Ir-Ir bonds are represented by the Re-Ir (or -Re) and Ir-Ir (or -Re) in the curve fitting
results. This is because it is very difficult to distinguish between Ir and Re as a back scattering atom.
Analyzes of EXAFS data were performed using a computer program (REX2000, ver. 2. 5. 9;
Rigaku Corp.).
The Ir L3-edge EXAFS results of Ir-ReOx/SiO2 after the hydrogenolysis of tetrahydrofurfuryl
alcohol are shown in Figure S3 and Table S1. The curve fitting results show that Ir-Ir (or -Re) bond
with bond distance of 0.276 nm and coordination number (CN) of 10.6 over Ir-ReOx/SiO2. This
result is similar to that of Ir-ReOx/SiO2 (Re/Ir=1) after the hydrogenolysis of glycerol
(distance=0.268 nm, CN=10.5) [S2].
The Re L3-edge EXAFS results of Ir-ReOx/SiO2 after the hydrogenolysis of tetrahydrofurfuryl
alcohol are shown in Figure S4 and Table S2. The curve fitting analysis indicates the presence of
the Re-O and Re-Ir (or -Re) bonds with bond distance of 0.203 nm and 0.268 nm, respectively, for
the both catalysts with Re/Ir =1 and 2. The presence of the Re-O bond indicates that Re species is
not fully reduced to the metallic state. This result is similar to that of Ir-ReOx/SiO2 after the
hydrogenolysis of glycerol [S2].
4

120
220
(ΙΙ)
(Ι)
20
15
110
100
90
205
190
175
160
b
b
a
a
80
0
1
2
3
4
5
6
2
4
6
8
10
12
k / 10 nm-1
Distance / 0.1 nm
.
.
(ΙΙΙ)
10
b
a
2
4
6
8
10
12
k / 10 nm-1
.
Figure S3. Results of Ir L3-edge EXAFS analysis of Ir-ReOx/SiO2 after the hydrogenolysis of tetrahydrofurfuryl
alcohol. I. k3-Weighted EXAFS oscillations. II. Fourier transform of k3-weighted Ir L3-edge EXAFS, FT range:
30-118 nm-1 (after the catalytic use). III. Fourier filtered EXAFS data (solid line) and calculated data (dotted
line), Fourier filtering range: 0.157-0.325 nm. a: Ir-ReOx/SiO2 (Re/Ir=1), b: Ir-ReOx/SiO2 (Re/Ir=2).
Table S1. Curve fitting results of Ir L3-edge EXAFS of Ir-ReOx/SiO2 after the hydrogenolysis of
tetrahydrofurfuryl alcohol.
Catalyst
Re/Ir molar ratio Shells
CNa R / 10-1 nmb σ / 10-1 nmc
ΔE0 / eVd
-3.0
Rf / %e
1.1
Ir-ReOx/SiO2
1
2
Ir-Ir (or –Re) 10.6 2.76
Ir-Ir (or –Re) 10.6 2.76
0.067
0.069
-2.2
1.0
aCoordination number. bBond distance. cDebye-Waller factor. dDifference in the origin of photoelectron energy
between the reference and the sample. eResidual factor. Fourier filtering range: 0.157-0.325 nm.
5

180
110
(Ι)
(ΙΙ)
10
10
170
160
150
140
130
100
90
b
a
×2
×2
b
a
80
70
60
2
4
6
8
10
12
0
1
2
3
4
5
6
k / 10 nm-1
Distance / 0.1 nm
.
.
95
(ΙΙΙ)
10
b
a
85
75
65
55
2
4
6
8
10
12
k / 10 nm-1
.
Figure S4. Results of Re L3-edge EXAFS analysis of Ir-ReOx/SiO2 after the hydrogenolysis of
tetrahydrofurfuryl alcohol. I. k3-Weighted EXAFS oscillations. II. Fourier transform of k3-weighted Re L3-edge
EXAFS, FT range: 30-120 nm-1. III. Fourier filtered EXAFS data (solid line) and calculated data (dotted line),
Fourier filtering range: 0.129-0.316 nm. a: Ir-ReOx/SiO2 (Re/Ir=1), b: Ir-ReOx/SiO2 (Re/Ir=2).
Table S2. Curve fitting results of Re L3-edge EXAFS of Ir-ReOx/SiO2 catalyst after the hydrogenolysis of
tetrahydrofurfuryl alcohol.
Catalyst
Re/Ir molar ratio Shells
CNa
1.4
R / 10-1 nmb σ / 10-1 nmc ΔE0 / eVd
Rf / %e
1
Re-O
2.03
2.68
2.03
2.68
0.071
0.080
0.076
0.074
-3.7
4.1
2.5
Ir-ReOx/SiO2
Re-Ir (or –Re) 6.2
Re-O 1.5
Re-Ir (or –Re) 6.2
2
-2.2
3.5
2.4
aCoordination number. bBond distance. cDebye-Waller factor. dDifference in the origin of photoelectron energy
between the reference and the sample. eResidual factor. Fourier filtering range: 0.129-0.316 nm.
6

References
[S1] S. R. Sashital, J. B. Cohen, R. L. Burwell Jr., J. B. butt, J. Catal. 50 (1977) 479.
[S2] Y. Amada, Y. Shimi, S. Koso, T. Kubata, Y. Nakagawa, K. Tomishige, Appl. Catal. B 105
(2011) 117.
[S3] A. L. Ankudinov, B. Ravel, J. J. Rehr, S. D. Conradson, Phys. Rev. B 58 (1998) 7565.
7

4. Example of 1H NMR of the reaction solution (Table 8, entry 2)
8