Enhanced hydrogenation of ethyl-levulinate to γ-valerolactone over Ni:δOx stabilized Cu+ surface sites

Article abstract of DOI:10.1039/c6ra16816g

CuNi^δO_x/SiO₂ nanocatalysts with Cu-Ni activities below 5 nm were synthesized. The catalysts showed high performance for catalytic hydrogenation of ethyl-levulinate to γ-valerolactone under mild reaction conditions. The composition and structure of these nanocatalysts were characterized. It is shown that Ni^δO_x plays a key role in stabilizing Cu⁺ against inactivation. To meet the requirements for industrial application, the CuNi^δO_x/SiO₂ nanocatalysts were tested under continuous reaction for over 2000 hours. The conversion and product selectivity were maintained at 100% and above 95%, respectively.

Full text of DOI:10.1039/c6ra16816g

View Article Online
View Journal
RSC Advances
This article can be cited before page numbers have been issued, to do this please use: K. Tang, J. Zhu
and Y. Tang, RSC Adv., 2016, DOI: 10.1039/C6RA16816G.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. This Accepted Manuscript will be replaced by the edited,
formatted and paginated article as soon as this is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/advances

Please do not adjust margins
RSC Advances
Page 1 of 5
View Article Online
DOI: 10.1039/C6RA16816G
Journal Name
COMMUNICATION
Enhanced Hydrogenation of Ethylꢀlevulinate to γꢀ
valerolactone over NiδOx Stabilized Cu+ surface sites
Junhua Zhu,a,b Yi Tang,*,a and Kangjian Tang,*,b
åReceived 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
CuNiδOx/SiO2 nanocatalysts with CuꢀNi activities below 5 nm
were synthesized. The catalysts showed high performance for
catalytic hydrogenation of ethylꢀlevulinate to γꢀvalerolactone at
mild reaction conditions. The composition and structure of these
nanocatalysts were characterized. It is shown that NiδOx play a
key role in stabilizing Cu+ against inactivation. To meet the
requirement of industrial application, the CuNiδOx/SiO2
nanocatalysts were tested under continuous reaction for over
2000 hours. The conversion and product selectivity maintained
at 100% and above 95%, respectively.
use in continuous flow. Current heterogeneous nobleꢀmetalꢀfree
catalysts were suffered from their poor stability.26
Gammaꢀvalerolactone (GVL) is an important chemical.1ꢀ3 It can be
used for producing liquid fuels,4 intermediate for synthesizing fine
chemicals,5 solvent,6ꢀ8 and flavoring agent.9 GVL can be obtained
from cellulose or hemiꢀcellulose by chemical methods, which make
it worthy of a “green” material.10 The chemical processes require a
certain catalytic steps via formation of levulinic acid (LA) or its
esters.11 The homogeneous or heterogeneous catalysts for the
conversion of LA or its esters to GVL have been studied.12ꢀ21
Homogeneous catalysts included metal Ph, Ru, Ir complexes and
heterogeneous catalysts included Ru, Pd, Au, Ag, Ni, Cu or their
alloy on inertia C, Al2O3, SiO2 or ZrO2 supports.16ꢀ21 In a batch
reaction, the homogeneous catalyst of shvoꢀtype ruthenium complex
could easily give a 99.9% conversion.[12] Meanwhile, heterogeneous
Ru/C, Ni/MoO3, Cu/ZrO2 catalysts could reach 99.9% conversion as
well at the temperature of 190 oC, 140 oC, and 200 oC, respectively.
Figure 1. Structural characterizations and catalytic performance of the
CuNiδOx nanoparticles (NP). (a) HRTEM image on a 20nm domain. (b) HRTEM
image of an individual CuNiδOx NP. There were two or more suits of lattices
However, to achieve sustainable GVL manufacture in industry,22 the shown by FFT result in blue box (see figure S1). (c) XPS coreꢀlevel spectra of
catalysts should: 1) be nobleꢀmetalꢀfree;23 2) possess high activity,
Ni2p3/2 and Cu2p, respectively.
selectivity, and longꢀtimed stability;24 3) use under mild conditions
Cuꢀbased catalyst has been studied as a good candidate, the
and friendly media; 4) work under continuous flow.25 To the best of
conversion could reach over 99.9%.19 However, the activity of Cuꢀ
our knowledge, the reported catalysts could not meet all of these
requirements. Homogeneous catalysts were expensive, and unable to
catalyst easily deactivates over 230 oC because of the coke and
o
based catalyst is extremely low below 200 C. Moreover, Cuꢀbased
aggregation of nanoactivities.26 To meet the industrial requirements,
it is important to improve the activity by stabilizing Cu+ over 200oC
or decrease the reaction temperature. So far, the efficient Cuꢀbased
catalyst is still hard to be developed. As known, the fabrication of
multicomponent active sites, such as metalꢀmetal oxide surface
sites,27 to facilitate the activation of reagents has been considered as
a.Department of Chemistry, Fudan University, Shanghai 200433, (P.R. China) Fax:
+86-21-65641740; Tel: +86-21-55664125 yitang@fudan.edu.cn
b.
Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai,
201208 (P. R. China). Fax: +86-21-68462283; Tel: +86-21-68462197-1202; E-mail:
tangkj.sshy@sinopec.com
c. Footnotes relating to the title and/or authors should appear here.
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
an effective method for heterogeneous catalysts with improved
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
RSC Advances
Page 2 of 5
View Article Online
DOI: 10.1039/C6RA16816G
COMMUNICATION
Journal Name
amount of introduced nickel. From Figure S6 and Table S1, the amount
of Cu+ reaches maximum as 4% nickel is added. Figure 3 shows the Xꢀ
ray diffraction (XRD) patterns of the asꢀprepared samples of
Ni(2%)/SiO2, Ni(8%)/SiO2, Cu(35%)/SiO2, Cu(35%)Ni(4%)/SiO2 and
Cu(35%)Ni(8%)/SiO2. Without Cu species, the XRD only show a broad
peak of SiO2 at around 25o when the amount of nickel below 2%. The
characteristic peaks of NiO (111), (200) and (220) at 2θ of 37.3o, 43.4o
and 62.8o can be observed when the nickel amount is 8%. Without Ni
species, the XRD show characteristic peaks of Cu2O (111) at 2θ of 37.1o,
and peaks of Cu (111) and (200) at 2θ of 43.2o and 50.4o. Since the peaks
at around 37o are affiliated to both Cu2O and NiO and the peaks at
around 43o are affiliated to Cu or NiO, we have to identify the structures
of Ni and Cu species based on the peaks at 50.4o and 62.8o, respectively.
performance. For example, Pt/FeOx surface sites exhibit excellent
performance in CO oxidation,28 Au/CeOx surface sites improve the
activity of the waterꢀgas shift reaction29 etc. In a previous work, it
have been studied the direct epoxidation of propylene over stabilized
Cu+ surface sites on titaniumꢀmodified Cu2O.30 The catalysis on Oꢀ
terminal molecule on Cuꢀbased catalysts was enhanced by Cu+. Here,
we reported a facile method to fabricate copperꢀnickel surface sites
and disperse highly on the SiO2 with grain size <5 nm in diameter.
The Cu+ꢀNiδOx surface sites greatly improved the catalytic
performance on hydrogenation of LA or ethylꢀlevulinate (EL) to γꢀ
valerolactone under mildꢀcondition. With this kind of catalyst, the
catalysis could maintain high activity (over 99% conversion and
95% selectivity) for over 2000 hours without decay, and well meet
the requirements of industry.
From
the
XRD
results
of
Cu(35%)Ni(4%)/SiO2
and
Cu(35%)Ni(8%)/SiO2 samples, the peaks affiliating to metal Cu is very
obvious but the peaks corresponding to copper oxides and nickel oxides
are not so clear. Therefore, the Cu2O, NiO and NiδOx with ultrafine grain
size are highly dispersed. It can be concluded that without the
introduction of the nickel, the Cu+ is mainly offered by chrysocolla (Cu2ꢀ
xSi2O5(OH)x because the featured XRD peaks at 2θ of 30o~32o in the
sample of CuNi(0)/SiO2 can be observed. The Cu+ is unstable during the
reaction and easy to aggregate to be bigger grains due to the weak
interaction between copper and silica. With the introduction of small
amount of nickel, the chrysocolla cannot be formed. NiꢀO species insert
into Cu and Si and take the place of promoting Cu+. With further
increasing the nickel content, an optimized dispersion of copper species
could be obtained based on the threshold of dispersing NiꢀO species on
silica. However, excess introduction of nickel leads to the aggregation of
part of nickel oxide, on which the tiny copper sites have the chance of
over growth.
Figure 2. STEMꢀEDS elemental mapping on a 20nm domain of CuNiδOx/SiO2
catalyst.
High resolution transmission electron microscopy (HRTEM) images
(Figure 1a and b) reveal the activities on substrates are very fine
nanoparticles with less than 5nm diameter. Lattice fringes with inter
planar distances of 0.21nm, corresponding to Cu (111) planes, can be
obviously observed (Figure S2). Energy dispersive spectroscopy (EDS)
analysis shows that this domain mainly contains Cu, Ni and Si (Figure
S3). Figure 1c shows the Cu xꢀray photoelectron spectroscopy (XPS),
suggesting the coexistence of Cu+ oxidation state and Cu0 metal state.
The Ni XPS suggests the coexistence of Ni2+ oxidation state and Niδ
(0≤δ<2) hemiꢀoxidation state. The CuNiδOx/SiO2 catalyst was also
characterized by an aberrationꢀcorrected scanning transmission electron
microscopy (STEM). STEMꢀEDS measurements show that the copper
and nickel are mixed well on the surface. EDX mapping analysis (Figure
2) on a 20nm domain and a larger area (Figure S4) reveals that the
appearance of Cu is always coupled with the presence of Ni, which
implies that the nickel atoms have strong bonding to copper atoms.
Furthermore, series of XPS spectra on copper and nickel with different
composition (Table S1, Table S2, Figure S5 and Figure S6) show that
the amount of Cu+ increases first and then decreases with increasing the
Figure 3. XRD curves of asꢀprepared catalysts.
Since the maximal Cu+ are obtained, we tested the aimed reaction of
catalytic hydrogenation of LA to GVL to evaluate the Cu+ꢀNiδOx surface
sites effect. Figure 4a displays hydrogenation activity of Cu/SiO2 and
CuNiδOx/SiO2 at the temperature of 230oC. Both catalysts could achieve
over 99% LA conversion at this temperature. However, pure Cu/SiO2
catalysts starts to lose its activity after 100 hours, and declines rapidly to
below 50%. The reason for the degradation was investigated by TEM, as
shown in Figure 4b. It is found that the Cu nanoparticles grow large
obviously after this period of reaction, which leads to the activity
decrease. In contrast, the CuNiδOx/SiO2 can hold both its reaction
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
RSC Advances
Page 3 of 5
View Article Online
DOI: 10.1039/C6RA16816G
Journal Name COMMUNICATION
blends. Due to the attainability of GVL and MTHF, the targeted
production of GVL and MTHF from EL becomes the focus of both
academic and industrial research efforts. Figure 4d shows the detailed
catalytic results on the optimized CuNiδOx/SiO2 catalyst. During the
2000 hours test, we investigated its conversion, temperatureꢀdependent
selectivity, stability and distribution of byproducts. Compared to
Cu/SiO2 catalyst works at 230oC, the CuNiδOx/SiO2 catalyst exhibits
o
over 99% conversion at about 155 C. Below 155 oC, the conversion
o
decreases sharply. Slowly increasing the reaction temperature to 230 C,
the conversion could be hold continuously at over 99% without any
decay. The whole selectivity (GVL+MTHF) could be kept over 90%
within the temperature range.
Table 1 shows the detailed data of temperatureꢀdependent selectivity
of GVL and MTHF. GVL and MTHF are complementary on selectivity.
Lower temperature is beneficial for producing GVL. The main product
distribution could be adjusted by simply changing temperature. It can be
seen that the GVL and MTHF could be obtained at the range from 150oC
to 250oC. Below 150oC the conversion could not reach 99% and over
250oC, 1ꢀpentanol became one of the main products. The optimal
temperature for producing GVL is from 155oC to 175oC. Significantly, it
is more than 60oC lower than that of the normal Cuꢀbased catalyst. This
work greatly extends the applied limitation of Cuꢀbased catalysts on lowꢀ
temperature catalysis. Table 2 listed the catalytic selectivity of Cuꢀ
Ni(0)/SiO2 to CuꢀNi(8%)/SiO2 catalysts at 230 oC. The selectivity
increases first and then decreases with increasing the amount of nickel.
CuꢀNi(4%)/SiO2 shows the best catalytic performance. Combining the
XPS and XRD results on series of CuꢀNi catalysts, it can be deduced that
the highly dispersed and stabilized Cu+ is the key for this hydrogenation
reaction and proper amount of nickel is necessary.
Table 1. Hydrogenation of EL to GVL and MTHF on Cu(35%)Ni(4%)/SiO2
catalyst. (%)
Conver
sion
(%)
79.37
99.92
99.96
99.99
99.99
99.99
99.99
2ꢀ
pentan
ol (%)
0
0
0
0.02
0.16
0.27
0.69
1ꢀ
pentan
ol (%)
0
T
MTHF
GVL
#others
(oC)
Figure 4. (a) LA conversions as a function of reaction time over CuNiδOx/SiO2
and Cu/SiO2 catalysts. (b) HRTEM image on a 20nm domain to verify the Cu/SiO2
catalyst after 100 hours’ reaction. (c) HRTEM image on a small domain to verify
the CuNiδOx/SiO2 catalyst after 200 hours’ reaction. (d) EL conversion as a
function of reaction time over CuNiδOx/SiO2 catalyst. brown line indicates the
changing of temperature; black line indicates the conversion rate; green line
indicates the whole selectivity of (GVL+MTHF); blue line and red line indicate
the selectivity of GVL and MTHF, respectively.
140
160
180
200
220
240
260
0
95.14
95.22
91.70
87.85
75.85
63.27
4.82
4.86
3.41
3.60
4.30
4.88
6.76
9.38
1.37
4.63
7.60
17.24
25.30
67.00
0
0.07
0.23
1.87
4.40
18.11
&1,4ꢀPentanediol; * Ethyl Valerate; #Unidentified
Table 2. Hydrogenation of EL to GVL and MTHF on Cu(35%)Ni(#)/SiO2
catalysts. (%)
ꢀactivity and stability within the testing time. Figure 4c shows the
compared TEM image of CuNiδOx/SiO2 nanocatalyst after 200 hours’
catalytic test. The particles’ size was most hold at about 5nm (the XRD
shown in figure S7 revealed that the structure of CuNiδOx/SiO2
nanocatalyst could be kept as good as fresh ones). In industry, this nobleꢀ
metalꢀfree Cu+ꢀNiδOx catalysts featured by high activity, selectivity and
stability should be work in friendly media and under mild continuous
flow condition. LA is a kind of acidic chemical. When using H2O as
solvent, the LA solution is harmful to metal reactors and the separation
of redundant H2O after hydrogenation increases energy cost. The
hydrogenation of ethylꢀlevulinate (EL) to GVL could solve the problem
very well. Herein, the ethyl alcohol was used as solvent and reactant to
LA. The reaction could be controlled in very low acidic environment and
ethyl alcohol could be directly recycled. As shown in scheme S1, a
controlled hydrogenation of EL to GVL at step 3 leads to GVL.
Meanwhile, the chemical, methyl tetrahydrofuran (MTHF), at step 5 is a
component of Pꢀseries fuels that are recently classified as alternative
fuels by the U.S. department of Energy. It is projected to be used as a
transportation fuel extender and has been successfully roadꢀtested in fuel
Conversi
on
GVL+M
THF
1ꢀ
pentanol
1.24
6.24
2.45
2ꢀ
pentanol
2.95
0.14
0.05
Catalyst
# others
Ni (0%)
Ni (2%)
Ni (4%)
Ni (6%)
Ni (8%)
98.95
98.90
99.99
99.54
99.63
92.24
91.16
93.22
90.01
85.88
3.57
2.46
4.28
6.07
7.13
3.79
6.71
0.13
0.28
#others included: 1,4ꢀpentanediol, ethyl valerate and some unidentified; Reaction
conditions: 230 , 3.0Mpa. The data were acquired after reaction for 100 hours.
Conclusions
In conclusion, a Cuꢀbased model catalyst by adding nickel to
improve performance has been explored for the reaction of LA to
GVL and EL to GVL. The proper amount of nickel could be
dominant for the optimized catalysis. The CuNiδOx oxide can
effectively stabilize surface Cu+ and is ideal for using in industry as
its over 99% conversion, 95% selectivity and over 2000 hours
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
RSC Advances
Page 4 of 5
View Article Online
DOI: 10.1039/C6RA16816G
COMMUNICATION
Journal Name
3.
4.
5.
6.
7.
X. Tang, X. Zeng, Z. Li, L. Hu, Y. Sun, S. Liu, T. Lei, L. Lin, Renew.
Sust. Energy Rev. 2014, 40, 608−620.
M.G. AlꢀShaal, A. Dzierbinski,R. Palkovits, Green Chem. 2014, 16,
1358−1364.
D. Wang, S.H. Hakim, D.M. Alonso, J.A. Dumesic, Chem. Commun.
2013, 49, 7040−7042.
L. Qi, Y. Mui, S. Lo, M. Lui, G.R. Akien, I.T. Horváth, ACS Catal.
2014, 4, 1470−1477.
stability. The strategy for the synthesis of stable mixed oxides
provides a simple method in catalyst preparation and selectivity
control. Results from the current study demonstrate the high
potential to synthesize mixed metal oxides catalysts for practical
applications.
Acknowledgements
The authors thank the partially financial support from the SINOPEC,
National Natural Science Foundation of China (NSFC 21373272 and
2013CB93410).
J.S. Luterbacher, J.M. Rand, M.D. Alonso, J. Han, J.T. Youngquist,
C.T. Maravelias, B.F. Pfleger, J.A. Dumesic, Science, 2014, 343,
277−280.
8.
9.
E.I. Gürbüz, J.M. Gallo, D.M. Alonso, S.G. Wettstein, W.Y. Lim, J.A.
Dumesic, Angew. Chem. Int. Ed. 2013, 52, 1270−1274.
S. Tanaka, K. Fukuda, T. Asada, (Kao Corp.). Patent No.
EP1555261A1, 2005.
Notes and references
† Electronic Supplementary Information (ESI) available: FFT pattern and
HRTEM of on one nanoparticle; EDS and EDS mapping on small and large
areas; XPS and LMM XAES results. See DOI: 10.1039/b000000x/
10. G. Centi, R.A. van Santen, Catalysis for Renewables, Eds. Wileyꢀ
VCH: Weinheim, 2007.
11. R.J. van Putten, J.C. van der Waal, E, de Jong, C. B, Rasrendra, H.J.
Heeres,J.G. de Vries, Chem. Rev. 2013, 133, 1499−1597.
12. Y. Blum, D. Reshef, Y. Shvo, Tetrahedron Lett. 1981, 22, 1541−1544.
13. J. Deng, Y. Wang, T. Pan, Q. Xu, Q. Guo, Y. Fu, ChemSusChem,
2013, 6, 1163−1167.
14. C. OrtizꢀCervantes, J. García, J. Inorg. Chim. Acta. 2013, 397,
124−128.
15. W. Li, J. Xie, H. Lin, Q. Zhou, Green Chem. 2012, 14, 2388−2390.
16. M.G. AlꢀShaal, W.R.H. Wright, R. Palkovits, Green Chem. 2012, 14,
1260−1263.
17. K. Yan, T. Lafleur, G. Wu, J. Liao, C. Ceng, X. Xie, Appl. Catal. A:
Gen. 2013, 468, 52−58.
18. X. Du, L. He, S. Zhao, Y. Liu, Y. Cao, H. He, K. Fan, Angew. Chem.
Int. Ed. 2011, 50, 7815−7819.
19. J. Yuan, S, Li, L. Yu, Y. Liu, Y. Cao, H. He, K. Fan, Energy Environ.
Sci. 2013, 6, 3308−3313.
20. A.M. Hengne, A.V. Malawadkar, N.S. Biradar, C.V. Rode, RSC Adv.
2014, 4, 9730−9736.
Experimental
The Cuꢀbased catalysts were prepared by a coꢀprecipitation method in which
0.20M aqueous solution of Cu(NO3)2.3H2O and proper amount of silica sol were
taken and precipitated using 0.2M aqueous sodium carbonate at ambient
temperature. The precipitate was aged further for 8 h at 60 oC. Then the mixture
was separated by filtration and washed with deionized water to remove the traces
of sodium. The solid thus obtained was dried in static oven at 110 oC for 24 h and
calcined at 400 oC for 4 h. The weight percentage of copper in the Cu/SiO2
catalyst was 35%. Cu+ꢀNiδOx/SiO2 catalysts were prepared by the same method,
and different amount of Ni(NO3)2.3H2O were introduced at ambient temperature.
Xꢀray powder diffraction (XRD) patterns on series of catalysts were recorded
in the range of 5~80° on Bruker D8 diffractometer using Cu Kα radiation with a
scanning step 0.002°, voltage 40kV, and current 100mA. High resolution
Transmission Electron Microscopy (TEM) was recorded on a FEI TECNAIꢀ20
instrument with accelerating voltage of 200 kV. TEM specimen was prepared by
dispersing the powder in alcohol by ultrasonic treatment and dropping onto a
21. Y. Yang, G. Gao, X. Zhang, F. Li, ACS Catal. 2014, 4, 1419−1425.
holey carbon film supported on a copper grid, and then dried in air. Scanning 22. P.C. Bruijnincx, Y. RománꢀLeshko, Catal. Sci. Technol. 2014. 4,
2180ꢀ2181
transmission electron microscopy (STEM) was performed on a doubleꢀcorrected
Titan Cubed 60ꢀ300 and a cold field emission gun was operated at 200 kV. STEM
images were recorded using a highꢀangle annular darkꢀfield (HAADF) detector.
Temperature dependant XPS studies were performed on a Kratos AXIS Ultra DLD
23. K. Yan, A. Chen, Fuel 2014, 115, 101−108.
24. D. Pletcher, F. Walsh, Industrial Electrochemistry, Springer: London,
U.K., 1990, 83.
25. C. Wiles, P. Watts, Green Chem. 2014, 16, 55−62.
26. B. Putrakumar, N. Nagaraju, V.P. Kumar, K.V.R. Chary, Catalysis
Today, 2015, 250, 209–217
27. Q. Fu, W. Li, X. Bao, et al., Science, 2010, 328, 1141–1144.M. S.
Chen, D. W. Goodman, Science, 2004, 306, 252–255.
28. B. Qiao, A. Wang, X. Yang, L.F. Allard, Z. Jiang, Y. Cui, J. Liu, J. Li,
T. Zhang, Nat. Chem. 2011, 3, 634–641.
29. J. A. Rodriguez, S. Ma, P. Liu, J. Hrbek, J. Evans, M. Pérez, Science,
2007, 318, 1757–1760.
spectrometer equipped with
a high temperature gas reaction cell. Catalysts
reduction was carried out in the reaction cell with increasing temperature and
feeding hydrogen. All the spectrum well collected with monochromatic Al Kα The
C 1s peak at 284.8 eV was set as reference for binding energy calibration. All the
spectrum processing and peak fitting were performed with CasaXPS.
All the reactions were carried out in a continuous flow, fixedꢀbed reactor and
5g catalysts were packed in the reactor. Prior to the reaction, the catalyst was
reduced at 400 oC in H2 flow. Ethylꢀlevulinate and ethanol solvent (EL/ethanol
volume ratio was 1/1) were fed into the reactor using an injection pump, and the
WHSV flow rate of EL was 0.6 hꢀ1. The reaction temperature was adjusted
between 140oC and 250oC. The reaction pressure was maintained at 3.0 MPa. The
molar ratio of hydrogen to EL was set as 50 (mol/mol). The hydrogenation
products were analyzed using gas chromatography (Agilent 7890) equipped with a
flame ionization detector and a capillary column (DBꢀ200). The main products and
byproducts were identified by GCꢀMS method on Agilent 5975C inert XL EI/CI
MSD.
30. X. Yang, S. Kattel, K. Xiong, K. Mudiyanselage, S. Rykov, S.D.
Senanayake, J.A. Rodriguez, P. Liu, D.J. Stacchiola, J.G. Chen,
Angew. Chem. Int. Ed. 2015, 54, 11946 –11951.
References
1.
I.T. Horváth, H. Mehdi, V. Fabos, L. Boda, L.T. Mika, Green Chem.
2008, 10, 238−242.
2.
Y. Gu, F. Jérôme, Chem. Soc. Rev. 2013, 42, 9550−9570.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 5
RSC Advances
View Article Online
DOI: 10.1039/C6RA16816G
156x151mm (300 x 300 DPI)