Highly selective catalytic conversion of furfural to γ-butyrolactone

Article abstract of DOI:10.1039/c5gc02411k

A two-step process was developed for the production of γ-butyrolactone (GBL) from furfural. Furfural was first oxidized using homogeneous acid catalysts under mild conditions in an aqueous/organic bi-phasic system to obtain 2(5H)-furanone, which was then selectively hydrogenated to GBL with a high yield over supported metal catalysts.

Full text of DOI:10.1039/c5gc02411k

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Green Chemistry
COMMUNICATION
Highly selective catalytic conversion of furfural to γ-butyrolactone
Xiaodan Li, Xiaocheng Lan and Tiefeng Wang*
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
A two-step process was developed for the production of γ-
butyrolactone (GBL) from furfural. Furfural was first oxidized using
homogeneous acid catalysts under mild conditions in an
aqueous/organic bi-phasic system to obtain 2(5H)-furanone,
which was then selectively hydrogenated to GBL with a high yield
over supported metal catalysts.
The conversion of lignocellulosic biomass to fuels and chemicals has
received considerable attention due to its environmental, economic,
and strategic advantages.1 Furfural, a renewable platform compound
produced by hydrolysis and dehydration of xylan contained in
lignocellulose, has already been used to produce fine chemicals such
as furfuryl alcohol, tetrahydrofurfuryl alcohol, furan, and furfural
resin in industry.2-4 In recent years, a variety of new processes
including oxidation, hydrogenation and hydrogenolysis have been
developed for the direct or indirect conversion of furfural into high
value-added molecules, such as 1,5-pentanediol, 1,2-pentanediol,
cyclopentanone, γ-valerolactone (GVL) and γ-butyrolactone (GBL).2,
Scheme 1 Illustration of the proposed conversion of furfural to GBL.
acids, which can be used for the synthesis of diols and lactones. Lan
et al.12 reported the aerobic oxidation of furfural to 54.0% yield of
maleic anhydride with H5PV2Mo10O40 and Cu(CF3SO3)2 as catalysts,
while Choudhary et al.13 realized aqueous oxidation of furfural to
succinic acid (SA) in 74.2% yield using Amberlyst-15 as catalyst.
Maleic anhydride or SA can then be used to produce GBL, BDO and
THF, whereas noble metal catalysts with a high loading, high
pressure (5~20 MPa) and high temperature (423~573 K) are
generally needed.14
5-9
Among these products, GBL, an important chemical intermediate
and solvent that has been widely used in the fields of chemical,
medicine, spice and fine organic synthesis, is considered most
attractive.10
GBL is mainly produced by dehydrocyclization of 1,4-
butanediol (BDO) or hydrogenation of maleic anhydride, which is
manufactured primarily from fossil feedstock.11 However, due to the
diminishing supply of fossil resource, the current research trend for
GBL production moves toward the utilization of renewable resources
such as biomass. In earlier studies, furfural was first transformed to
tetrahydrofuran (THF) by decarbonxylation and hydrogenation, and
THF was then oxidized to produce GBL.2 However, this method has
limitations because of its harsh conditions, complicated process and
low yield. Recently, substantial interest has been devoted to the
selective oxidation of furfural to acid anhydrides or dicarboxylic
In addition to dicarboxylic acids and acid anhydrides, furfural
can also be oxidized to 2(5H)-furanone. The molecule structure of
2(5H)-furanone contains only one additional C=C bond than GBL,
making it a potential intermediate for the conversion of furfural to
GBL. Cao et al.15 reported a convenient synthesis of 2(5H)-furanone
from furfural by autocatalysis with dichloroethane as solvent, but
more than 10 hours were required to obtain a 37% yield. Badovskaya
et al.16 investigated furfural oxidation in the presence of Mo (VI) or
Cr (VI), but did not get an improved yield of 2(5H)-furanone.
Although the oxidation of furfural to 2(5H)-furanone has been
studied for decades, most works use homogeneous catalysts and
chlorinated solvents and the yield of 2(5H)-furanone is still moderate
ranging from 30~50%. The atom economy of producing GBL from
furfural with 2(5H)-furanone as intermediate is much higher than
that with dicarboxylic acid or anhydride as intermediate, but few
studies have been reported on the hydrogenation of 2(5H)-furanone.
Beijing Key Laboratory of Green Reaction Engineering and Technology,
Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
E-mail: wangtf@tsinghua.edu.cn; Tel: +86-10-62794132.
†Electronic Supplementary Information (ESI) available. See DOI: 10.1039/
x0xx00000x
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Herein, we report a two-step process to produce GBL from the (Table 1, entries 1-6), a bi-phasic reaction system consisting of an
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DOI: 10.1039/C5GC02411K
biomass derived platform compound furfural with 2(5H)-furanone as aqueous phase and an organic phase was formed. A 60.3% yield of
the intermediate (Scheme 1). In the first step, furfural was oxidized 2(5H)-furanone was obtained from the organic phase when using
to 2(5H)-furanone with a yield of 61.5% in a bi-phasic system using 1,2-dichloroethane as solvent, meanwhile the water soluble
formic acid as catalyst, ethyl acetate as solvent and hydrogen byproducts MA and SA were in the aqueous phase with a yield of
peroxide as oxidant. In the second step, the purified 2(5H)-furanone 12.0% and 6.3%, respectively. When tetrachloromethane was used
was further hydrogenated to GBL using supported metal catalysts. as solvent, the yield of 2(5H)-furanone decreased to 40.2%.
Pd0.5/SiO2 gave the best performance among the selected catalysts, However, the introduction of benzene or toluene as solvent caused
with a high GBL selectivity of 92.6% when 2(5H)-furanone was severe non-catalytic polymerization of furfural, and the liquid turned
completely converted. To the best of our knowledge, this is the first brown gradually. Considering the environmental issues, water or
report on selective hydrogenation of 2(5H)-furanone to GBL.
organic solvents with low toxicity are preferred.17 When distilled
In the initial studies of furfural oxidation, various homogeneous water was used as solvent, the yield of 2(5H)-furanone was only
and heterogeneous acid catalysts were evaluated using 1,2- 3.2% (Table 1, entry 6). By decreasing the amount of furfural for
dichloroethane as solvent (Table S1). The blank experiment without complete dissolution in water, the yield of 2(5H)-furanone was
catalyst gave a 2.6% yield of 2(5H)-furanone at a very low increased to 27.8% (Table 1, entry 7). Ethyl acetate, a moderate
conversion. Among the selected acid catalysts, formic acid was solvent with low toxicity, was found to be an ideal substitute for 1,2-
found to exhibit the highest activity for converting furfural to 2(5H)- dichloroethane, giving 61.5% yield of 2(5H)-furanone, 6.7% yield of
furanone, with a 60.3% yield of 2(5H)-furanone obtained. The MA and 8.5% yield of SA. In homogeneous systems with methanol,
reason for this high yield is that formic acid can react with hydrogen isopropanol, GBL and THF as solvents (Table 1, entries 8-11), SA
peroxide to generate performic acid, which is the real active oxidant was the major product and the yields of 2(5H)-furanone and MA
with strong oxidizing nature and good solubility in both aqueous and were below 20%. Besides, the yield of SA was improved with an
organic phases. The molar ratio of formic acid/furfural was increase in the dielectric constant of the solvent. The formation of
optimized (Figure S1). When other acid catalysts were used, SA or some GC and HPLC-silent products via polymerization or deep
maleic acid (MA) was the main product and the yield of 2(5H)- oxidation caused incomplete carbon balance. In the bi-phasic system,
furanone was less than 20%.
2(5H)-furanone and the water soluble byproducts like MA and SA
The solvent plays an important role in oxidation of furfural to were separated simply by stratification after the reaction. 2(5H)-
2(5H)-furanone. To study the solvent effect, the furfural oxidation furanone was separated from the organic phase through vacuum
reaction was carried out in both bi-phasic and homogeneous systems distillation. The purification of 2(5H)-furanone prevented the
using a variety of solvents with formic acid as catalyst and hydrogen introduction of acid compounds such as formic acid into the
peroxide as oxidant. When 1,2-dichloroethane, tetrachloromethane, hydrogenation reaction system, which may accelerate side reactions
benzene, toluene, ethyl acetate or distilled water was used as solvent
and decrease the selectivity to GBL. The purified 2(5H)-furanone
was then hydrogenated in the second step.
Having obtained 2(5H)-furanone by furfural oxidation, we next
turn to the hydrogenation of 2(5H)-furanone to GBL. 2(5H)-
furanone has two unsaturated bonds, namely the conjugated C=O
Table 1 Reaction results of furfural oxidation with different solvents a
Table 2 Properties and catalytic performances of SiO2 supported Group VIII
Yield b (%)
metals
Entry
Solvent
2(5H)-furanone
60.3
MA
12.0
11.3
7.3
SA
6.3
Total
78.6
60.1
d, f
CO-uptake b Metal dispersion
kr
Selectivity to
Entry Catalyst a
1
2
1,2-dichloroethane
Tetrachloromethane
Benzene
(10-6 mol/g)
(%)
(10-2min-1) GBL e,f (%)
40.2
8.6
1
2
Ni4.5/SiO2
Co4.5/SiO2
18.9
22.5
—
2.5
2.9
1.8
14.5
4.7
6.1
4.3
2.4
1.8
0.3
1.4
7.8
7.7
1.6
91.6
87.2
91.4
70.4
92.6
91.3
89.2
3
8.9
10.1
4.9
26.3
26.3
4
Toluene
12.2
9.2
3 c Cu4.5/SiO2
5
Ethyl acetate
Distilled water
Distilled water
Isopropanol
Methanol
61.5
6.7
8.5
76.7
9.0
4
5
6
7
Pt0.5/SiO2
Pd0.5/SiO2
Rh0.5/SiO2
Ru0.5/SiO2
3.7
2.2
3.0
2.1
6
7 c
3.2
1.1
4.7
27.8
8.1
39.8
26.4
35.3
38.3
25.6
75.7
49.0
60.4
68.4
53.8
8
11.3
11.3
12.0
17.3
10.0
9
13.1
10
11
GBL
12.8
a The monometallic catalysts were denoted as Mx/SiO2, where x was the loading in
THF
18.2
b
wt% of the supported metals. Each absorbed CO molecule was assumed to
correspond to one active site. c The metal dispersion of Cu was determined by H2-
a
Reaction conditions: furfural (4.0 g), solvent (10 mL), H2O2 (30%, 10 mL),
d
N2O titration. The reaction order was fixed at 1.0. e The selectivity to GBL was
b
Na2SO4 (4.0 g), formic acid (88%, 1.5 mL), 333 K, 3 h. The yields of products
f
c
calculated with 2(5H)-furanone just completely converted. Reaction conditions:
were calculated when furfural was just completely converted. Furfural was
2(5H)-furanone (6.0 g), catalyst (0.6 g), methanol as solvent (100 mL), 353 K, 3.5
completely dissolved in the solvent (1 g furfural/ 9 mL distilled water) and the
reaction system turned to be homogeneous, in nitrogen .
MPa H2, 180 mL/min H2 gas flow, 800 r/min stirring.
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Fig 1 Correlation of initial TOF for 2(5H)-furanone hydrogenation with d-band Fig 2 Correlation of the selectivity to GBL with d-band width. 2(5H)-furanone (6.0
center relative to Fermi level. 2(5H)-furanone (6.0 g), catalyst (0.6 g), methanol as g), catalyst (0.6 g), methanol as solvent (100 mL), 353 K, 3.5 MPa, 180 mL/min H2
solvent (100 mL), 353 K, 3.5 MPa, 180 mL/min H2 gas flow, 800 r/min stirring.
gas flow, 800 r/min stirring.
and C=C bonds. The selective hydrogenation of C=C bond over SiO2 metal catalysts.19 The volcano-type relationship between activities
or TiO2 supported Group VIII metals was studied in liquid phase. A and d-band center has been established for several other reaction
series of SiO2 and TiO2 supported metal (M = Pt, Pd, Rh, Ru, Ni, Co systems.20 According to the d-band model proposed by Nørskov, the
and Cu) catalysts were prepared by incipient wetness impregnation. binding energy of adsorbates decreases when the d-band center shifts
TEM and Chemisorption were respectively used to estimate the away from the Fermi level.21 The binding energies of small
metal particle size distribution (Figure S2) and the metal dispersion absorbates such as hydrogen, alkene containing C=C bond and
(Table 2, Table S2) of the catalysts. As listed in Table 2, significant oxygenates containing C=O bond have been correlated with the d-
differences exist in the reaction rate and product distribution among band center for Group VIII metals.22 The nearly linear correlations
different metal catalysts. The Pd0.5/SiO2 catalyst showed a better verify the effectiveness of Nørskov’s model. Therefore, the binding
performance than the others, giving a reaction rate constant of 0.078 energy of 2(5H)-furanone over the selected Group VIII metals is
min-1 and GBL selectivity of 92.6%. Moreover, the Pd0.5/SiO2 considered to follow the trend of Cu < Pt < Pd < Rh < Ru < Ni < Co.
catalyst was found to be stable and reusable, retaining its The curve in Fig 1 indicates that the value of the d-band center of Pd
hydrogenation activity and selectivity to GBL after 5 runs (Figure corresponds to a 2(5H)-furanone binding energy that is optimal for
S3). The Ni4.5/SiO2 catalyst had the highest activity (0.024 min-1) hydrogenation. Stronger binding energy may lead to surface
and selectivity to GBL (91.6%) among the selected non-noble metal poisoning, while weaker binding energy may limit the availability of
catalysts. From the view of cost, Ni4.5/SiO2 is much cheaper than 2(5H)-furanone, therefore in both cases the catalytic activities are
Pd0.5/SiO2 for industrial applications. For the SiO2 supported metal lower than the optimal.
catalysts, the reaction rate constant followed the trend of Pd0.5/SiO2
~ Rh0.5/SiO2 > Ru0.5/SiO2 > Pt0.5/SiO2, and Ni4.5/SiO2
As shown in Table 2, a wide variation in selectivity to GBL is
observed over different SiO2 supported metal catalysts. Among the
>
Co4.5/SiO2 > Cu4.5/SiO2. When Ni, Co, Pt and Pd were supported selected metals, Ni, Pd and Rh are more selective towards C=C
on TiO2, the reaction rate constants were 0.025 min-1, 0.018min-1, hydrogenation than C=O hydrogenation and the ring opening, with a
0.015min-1 and 0.047 min-1, respectively, showing a similar trend to selectivity of 91.6%, 92.6% and 91.3%, respectively. Figure 2 shows
that of the SiO2 supported catalysts. The decrease of hydrogenation a plot of selectivity to GBL vs the width of the metal d-band, which
activity of the Pd0.5/TiO2 catalyst with a lower reaction rate constant is an empirical indicator of the electronic structure of the transition
than that over Pd0.5/SiO2 may be caused by the partial coverage of metals.19, 23 It can be seen that the narrower the width of the metal d-
metal active sites due to the strong metal-support interaction.
band, the higher the selectivity to GBL. This is consistent with the
To further discuss the catalyst activity, the initial turnover theoretical calculations reported by Delbecq and Sautet23, who
frequency (TOF) for 2(5H)-furanone hydrogenation over the SiO2 showed that a narrower d-band width allowed greater interaction
supported metal catalysts is plotted in Figure 1 as a function of the d- between the C=C bond and metal surface and benefited the selective
band center (εd) relative to the Fermi level (EF). The number of hydrogenation of C=C bond. However, when the d-band width
active sites was determined by chemisorption, and the values of εd decreased to a certain value, a slight decrease of selectivity was
were taken from ref 18. A volcano-type relationship was observed observed. When Ni, Co, Pt and Pd were supported on TiO2, a similar
with Pd showing the maximum activity. A similar volcano-type trend in selectivity to GBL was obtained. For the same metal, the
correlation was obtained when using the number of active sites selectivity to GBL over M/TiO2 was lower than that over M/SiO2.
estimated from the TEM images (Figure S4). The d-band center is a This may be due to the partial coverage of the metal active sites and
useful parameter to describe electronic state of the entire valence the generation of new sites that can accelerate side reactions (Figure
band of the metal surface, which is responsible for the activities of S5). The decreased selectivity to GBL is mainly caused by
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polymerization of cyclic organics and side reactions including 13 H. Choudhary, S. Nishimura and K. Ebitani, Appl. Catal. A, 2013, 458, 55.
View Article Online
DOI: 10.1039/C5GC02411K
hydrogenation of C=O bond, ring opening and excess hydrogenation. 14 C. Delhomme, D. Weuster- Botz and F. E. Kühn, Green Chem., 2009, 11, 13.
15 R. Z. Cao, C. Liu and L. Z. Liu, Org. Pre. Proced. Int., 1996, 28, 215.
16 L. A. Badovskaya, V. M. Latashko, V. V. Poskonin, E. P. Grunskaya, Z. I.
Conclusions
Tyukhteneva, S. G. Rudakova, S. A. Pestunova, and A. V. Sarkisyan, J.
A two-step process for production of GBL from furfural was
Heterocycl. Chem., 2002, 38, 1040.
developed, providing a new strategy for converting biomass derived 17 K. Alfonsi, J. Colberg, P. J. Dunn, T. Fevig, S. Jennings, T. A. Johnson, H. P.
platform compound to high value-added fine chemicals. The highest
yield of 2(5H)-furanone (61.5%) was obtained from furfural
Kleine, C. Knight, M. A. Nagy, D. A. Perry and M. Stefaniak, Green Chem.,
2008, 10, 31.
oxidation reaction in a bi-phasic system with formic acid as catalyst, 18 A.Ruban, B. Hammer, P.Stoltze, H. L. Skriver and J. K. Nørskov, J. Mol.
ethyl acetate as solvent, and hydrogen peroxide as oxidant. Then Catal. A: Chem., 1997, 115, 421.
2(5H)-furanone was further hydrogenated to GBL with a high 19 B. Hammer and J. K. Nørskov, Surf. Sci., 1995, 343, 211.
selectivity of 92.6% over Pd0.5/SiO2 when 2(5H)-furanone was 20 (a) F. H. B. Lima, J. Zhang, M. H. Shao, K. Sasaki, M. B. Vukmirovic, E. A.
completely converted. The initial TOF for 2(5H)-furanone
hydrogenation over SiO2 supported Group VIII metals (M= Pt, Pd,
Ticianelli and R. R. Adzic, J. Phys. Chem., 2007, 111, 404; (b) M. Tamura, K.
Kon, A. Satsuma and K. Shimizu, ACS Catal., 2012, 2, 1904.
Rh, Ru, Ni, Co and Cu) showed a volcano-type dependence on the 21 (a) B. Hammer, O. H. Nielsen and J. K. Nørskov, Catal. Lett., 1997, 46, 31; (b)
εd-EF value, with Pd having the highest activity. The variation of Y. Xu, A. V. Ruban and M. Mavrikakis, J. Am. Chem. Soc., 2004, 126, 4717.
selectivity to GBL over different supported metal catalysts was 22 (a) J. G. Chen, C. A. Menning and M. B. Zellner, Surf. Sci. Rep., 2008, 63, 201;
rationalized on the basis of the d-band width. These correlations can
guide the design of more efficient catalysts for the hydrogenation of
2(5H)-furanone to GBL.
(b) J. K. Nørskov, F. A. Pedersen, F. Studt and T. Bligaard, PNAS, 2011, 108,
937.
23 (a) F. Delbecq and P. Sautet, J. Catal., 1995, 152, 217; (b) C. S. Fadley and D.
A. Shirley, J. Res. Natl. Bur. Stand. A, 1970, 74, 543.
Acknowledgments
We thank the financial support by the Chinese Ministry of
Education (No. 113004A). We also thank Prof. Jingguang Chen for
valuable discussion.
Notes and references
1 (a) P. Gallezot, Chem. Soc. Rev., 2012, 41, 1538; (b) D. M. Alonso, J. Q. Bond
and J. A. Dumesic, Green Chem., 2010, 12, 1493.
2 J. P. Lange, E. van der Heide, J. van Buijtenen and R. Price, ChemSusChem,
2012, 5, 150.
3 S. Dutta, S. De, B. Saha and Md. I. Alam, Catal. Sci. Technol., 2012, 2, 2025.
4 K. Xiong, W. S. Lee, A. Bhan and J. G. Chen, ChemSusChem, 2014, 7, 2146.
5 (a) S. Liu, Y. Amada, M. Tamura, Y. Nakagawa and K. Tomishige, Catal. Sci.
Technol., 2014, 4, 2535; (b) W. J. Xu, H. F. Wang, X. H. Liu, J. W. Ren, Y. Q.
Wang and G. Z. Lu, Chem. Commun., 2011, 47, 3924.
6 T. Mizugaki, T. Yamakawa, Y. Nagatsu, Z. Maeno, T. Mitsudome, K.
Jitsukawa and K. Kaneda, ACS Sustainable Chem. Eng., 2014, 2, 2243.
7 (a) Y. L. Yang, Z. T. Du, Y. Z. Huang, F. Lu, F. Wang, J. Gao and J. Xu,
Green Chem., 2013, 15, 1932; (b) M. Hronec, K. Fulajtárova and T. Soták,
Appl. Catal. B, 2014, 154, 294.
8 (a) L. Bui, H. Luo, W. R. Gunther and Y. R. Leshkov, Angew. Chem., 2013,
125, 8180; (b) A. M. Hengne, S. B. Kamble and C. V. Rode, Green Chem.,
2013, 15, 2540.
9 C. Aellig, F. Jenny, D. Scholz, P. Wolf, I. Giovinazzo, F. Kollhoff and I.
Hermans, Catal. Sci. Technol., 2014, 4, 2326.
10 X. Li, Y. Y. Cui, X. L. Yang, W. L. Dai and K. N. Fan, Appl. Catal. A, 2013,
458, 63.
11 (a) N. Ichikawa, S. Sato, R. Takahashi, T. Sodesawa and K. Inui, J. Mol. Catal.
A: Chem., 2004, 212, 197; (b) T. J. Hu, H. B. Yin, R. C. Zhang, H. X. Wu, T.
S. Jiang and Y. J. Wada, Catal. Commun., 2007, 8, 193; (c) J. R. Ebner and V.
M. Francetti, Chem. Rev., 1988, 88, 55.
12 J. H. Lan, Z. Q. Chen, J. C. Lin and G. C. Yin, Green Chem., 2014, 16, 4351.
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A twoꢀstep strategy consisting of furfural oxidation and selective hydrogenation of
2(5H)ꢀfuranone was developed to produce γꢀbutyrolactone from furfural.