One-pot conversion of biomass-derived xylose and furfural into levulinate esters via acid catalysis

Article abstract of DOI:10.1039/c7cc01078h

Direct conversion of biomass-derived xylose and furfural into levulinic acid, a platform molecule, via acid-catalysis has been accomplished for the first time in dimethoxymethane/methanol. Dimethoxymethane acted as an electrophile to transform furfural into 5-hydroxymethylfurfural (HMF). Methanol suppressed both the polymerisation of the sugars/furans and the Aldol condensation of levulinic acid/ester.

Full text of DOI:10.1039/c7cc01078h

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One-pot Conversion of the Biomass-derived Xylose and Furfural
into Levulinate Esters via Acid Catalysis
Xun Hu, Shengjuan Jiang, Liping Wu, Shuai Wang and Chun-Zhu Li*
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
Direct conversion of biomass-derived xylose and furfural into developed to achieve the direct conversion of C5 sugars into
levulinic acid, a platform molecule, via acid-catalysis has been levulinic acid under mild conditions.
accomplished
for
the
first
time
in
The structural difference between HMF, the dehydration
dimethoxymethane/methanol. Dimethoxymethane acted as intermediate of C6 sugars,11 and furfural, the dehydration
the electrophile to transform furfural into 5- intermediate of C5 sugars,12 is the additional hydroxymethyl
hydroxymethylfurfual (HMF). Methanol suppressed both the group in HMF. If one hydroxymethyl group could be added to
polymerisation of the sugars/furans and the Aldol the furan ring in furfural, furfural would then be able to be
condensation of levulinic acid/ester.
transformed to HMF, and subsequently to levulinic acid. The
furan ring in furfural has aromaticity, and it is thus possible to
introduce the hydroxymethyl group to furfural via electrophilic
substitution.
Levulinic acid is the building block chemical for the
production of various value-added chemicals such as
pharmaceuticals, plasticizers and various other additives.1
Commercially, levulinic acid is produced from the hydrolysis of
biomass in the presence of a mineral acid with the yields
ranging from 10 to 30 wt.%.2 The low yields of levulinic acid
from biomass origin from two main reasons: (1) the
polymerisation of sugars during the conversion into levulinic
acid;3 (2) only the C6 sugar substrates (glucose unit) in
cellulose and in hemicelluloses (mannose and galactose units)
can be potentially converted into levulinic acid via acid
catalysis.4 The C5 sugar substrates (xylose and arabinose units)
under the same conditions are mainly converted into furfural,5
which is an intrinsic reason for the low yields of levulinic acid
from biomass.
In this study, we developed dimethoxymethane
(DMM)/methanol as an effective reaction medium to
transform xylose directly into levulinic acid/ester via acid
catalysis only. The overall reaction pathways for the
conversion of xylose into levulinic acid via acid catalysis were
proposed in Scheme 1. The yields of levulinic acid/ester
reached ca. 52% (150
which was comparable to the yields of levulinic acid from
glucose in water (ca. 50%, 180
C, Amberlyst 70, in water).13
°C, Amberlyst 70, in DMM/methanol),
°
These are the new reaction routes for the direct conversion of
xylose and furfural into levulinic acid under the mild reaction
conditions.
O
The C5 sugar like xylose can be converted into levulinic
acid,6 but via multiple steps including the initial acid-catalyzed
conversion to produce furfural in liquid phase,7 the following
partial hydrogenation of furfural to furfuryl alcohol in gas
phase8 or in liquid phase9 and the further acid-catalyzed
conversion of furfuryl alcohol into levulinic acid/ester in liquid
phase.10 The above process involves both hydrogenation and
acid-catalyzed reactions. It is preferable to avoid the
hydrogenation step as the hydrogenation involves the use of
hydrogenation catalyst, high pressure and hydrogen, making
the process complicate and costly. New strategy needs to be
O
R
HO
O
In DMM
O
O
O
O
(R = H or CH3
)
HO
OH
XylosOe H
O
Levulinic acid/ester
(Yields: 12.9%)
O
O
R
O
HO
HMF
In DMM/water
O
DMM
O
O
H
O
O
Levulinic acid/ester
(Yields: 9.6%)
O
O
HO
O
Furfural
O
methanol
O
R
O
O
In DMM/methanol
O
O
DMM
O
O
O
O
Levulinic acid/ester
(Yields: 51.9%)
O
O
DOF
Fuels and Energy Technology Institute, Curtin University of Technology, GPO Box
U1987, Perth, WA 6845, Australia
*Corresponding author: Tel: (+) 61 8 9266 1131 E-mail: chun-zhu.li@curtin.edu.au
Scheme 1 Conversion of xylose to levulinic acid/ester in DMM/co-solvent.
All the products were detected with GC-MS.
Electronic Supplementary
DOI: 10.1039/x0xx00000x
Information
(ESI)
available:
See
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Table 1 Conversion of xylose, glucose, furfural or HMF to levulinic acid (LA) and levulinic ester (LE)a
ARTICLE
Entry
Key parameters
Reactants
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Xylose
Yields (%)
Reaction medium
T(°C)
Catalyst(s)
A70
t (min)
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
360
120
LE
LA
LE+LA
1
DMM
140
150
160
170
180
150
150
150
150
150
150
150
150
150
150
150
150
160
160
150
160
13.9
12.2
6.4
1.2
0.7
1.6
1.4
0.1
4.6
0.4
1.6
0.9
1.7
7.1
1.4
2.1
2.1
3.0
2.2
1.2
1.6
3.8
10.3
0.3
15.1
12.9
8.0
2
A70
DMM
3
A70
DMM
4
A70
DMM
1.6
3.0
5
A70
DMM
0.2
0.3
6
A70
DMM/water
5.0
9.6
7
A70
DMM/DMSO
0.2
0.6
8
A70
DMM/THF
14.5
13.6
19.7
10.0
18.0
22.6
22.8
29.1
32.6
12.8
6.4
16.1
14.5
21.4
17.1
19.4
24.7
24.9
32.1
34.8
13.0
8.0
9
A70
DMM/diethyl ether
DMM/toluene
DMM/iso-propanol
DMM/methyl formate
DMM/ethanol
DMM/methanol (25/15)b
DMM/methanol (32.5/7.5)
DMM/methanol (29/11)
DMM/methanol (15/25)
DMM (40/0)
10
11
12
13
14
15
16
17
18
19
20
21
A70
A70
A70
A70
A70
A70
A70
A70
A70
A70
DMM/methanol (25/15)
DMM/methanol
DMM/methanol
37.7
41.6
3.1
41.5
51.9
3.4
A70
La(III)c
22
23
Xylose
Xylose
DMM/methanol
160
160
120
120
33.2
0
8.4
0
41.6
0
La(III) + A70
A70
Acetaldehyde
24
25
26
27
28
29
30
31
32
Xylose
DEM/water
160
160
160
160
160
160
160
160
160
A70
A70
A70
A70
A70
A70
A70
A70
A70
120
120
120
120
120
120
120
120
120
4.4
2.6
7.0
Xylose
DEM/methanol
DEM/ethanol
DMM/methanol
DMM/methanol
DMM/methanol
DMM
27.4
21.8
52.5
40.7
43.3
27.3
16.1
61.7
4.0
31.4
24.3
63.5
49.1
46.8
30.0
26.5
73.6
Xylose
2.5
Glucose
Glucose + xylose
Furfural
Furfural
Furfural
HMF
11.0
8.4
3.5
2.8
DMM/water
10.4
11.9
DMM/methanol
was not selective and the yields further decreased at higher
reaction temperatures.
aOther reaction conditions: saccharide: 1.8 g; Amberlyst 70 (A70): 3.6 g;
Solvent: 40 mL; t = 120 min; p = autogenous vapour pressure. bThe volume
ratio of the solvents. The volumetric ratio for the mixed solvents with no
Furfural is highly reactive towards polymerization.14 Soluble
polymers in the products were detected and their abundance
was increased with the reaction temperatures (Figure S2).
Abundant ketone functionalities in the insoluble polymer were
detected with FT-IR, especially above 150oC (Figure S3).
Polymerization of furfural was suspected as the main reason
for the low yields of levulinic acid/ester. DMM as the
solvent/reactant alone was not able to prevent the
polymerization. Co-solvent was thus employed herein to tackle
the polymerizations of xylose/furfural in DMM.
parenthesis
was
25:15.
cLa(III)
stands
for
Lanthanum(III)
trifluoromethanesulfonate. Distribution of other products was summarized
in Table S1 in supporting information.
Entry 1 to 5 in Table 1 shows the effects of reaction
temperature on the formation of levulinic ester (LE) and
levulinic acid (LA) from xylose in dimethoxymethane (DMM).
The electrophilic substitution between DMM and furfural took
place, transforming furfural into HMF or its derivatives (Figure
S1a in Supporting Information). The concept of transforming
furfural to HMF via the electrophilic substitution in DMM was
confirmed. However, the formation of LA or LE from xylose
Entry 6 to 14 in Table 1 shows the effects of co-solvents on
yields of levulinic acid/ester. It was found that toluene also
reacted with DMM to form aromatics (Scheme S1), which was
similar to the formation of HMF from furfural in terms of
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ARTICLE
mechanism. This is because both the furan ring and benzene product. Methanol or ethanol as the co-solvent of DEM
ring have the aromaticity, and they could react with DMM via promoted the formation of the levulinic esters.
the electrophilic substitution reactions. The reaction pathways
When glucose was used as a reactant, Levulinic acid/ester
for the transformation of furfural into the derivative of HMF yields reached ca. 63.5% (Entry 27), which was higher than
were proposed in Scheme S2. Among the co-solvents that in water (ca. 50%).13 For the mixed glucose/xylose, half of
investigated, methanol or ethanol could remarkably promote them were converted to levulinic acid/ester (Entry 28). In this
the production of levulinic acid/ester (Entry 13 and 14). The process, neither hydrogen nor hydrogenation catalyst was
positive effects of alcohols on levulinic acid/ester formation required. Using only an acid catalyst and DMM/methanol
were further investigated.
achieved simultaneous conversion of both the C5 and C6
Entry 14 to 19 in Table 1 shows the effects of methanol sugars into levulinic acid/ester. Conversion of the biomass-
content in reaction medium on levulinic acid/ester production. derived furans into levulinic acid/ester was also investigated in
With the addition of a small amount of methanol to the DMM/methanol.
reaction medium, the yields of levulinic acid/ester were more
Entry 29 to 32 in Table 1 shows the formation of levulinic
than doubled (Entry 15 versus Entry 2). Methanol could react acid/ester from furfural and HMF. With DMM/methanol as the
with furfural, forming 2-(dimethoxymethyl)furan (DOF, the reaction medium, the polymerization reactions could be
acetal of furfural) (Scheme 1). The formation of DOF destroyed effectively suppressed (Figure 1b). However, the yields of
the π-conjugation between the furan ring and the carbonyl levulinic acid/ester from furfural could not reach 50% (Entry
group, which possibly made the furan ring more susceptible to 29), which was similar to that from xylose (Entry 19).
the attack by the electrophile, facilitating the subsequent
Clearly, whether xylose or furfural as the starting reactant
electrophilic substitution reaction. More importantly, made no marked difference in terms of the yields of levulinic
methanol significantly suppressed the polymerization acid/ester (Entry 19 and 29), which was also confirmed by the
reactions. As evidenced in Figure 1a, the abundance of the conversion of xylose or furfural versus the reaction time
soluble polymers decreased remarkably with methanol as the (Figure S5, S6 and S7). Thus, the polymerization during the
co-solvent.
step from the conversion of xylose to furfural was not the
main reason for the loss of levulinic acid/ester production.
Other undesirable reactions must be responsible. The soluble
polymers formed from furfural or HMF in DMM/methanol
were very different from that in water (Figure S8), indicating
involvement of the polymerization other than that from xylose
or furfural.
(a)
T = 160oC
(b)
Xylose in DMM
Furfural in DMM
Furfural in DMM/water
Furfural in DMM/methanol
80
Xylose in DMM/methanol (32.5/7.5)
Xylose in DMM/methanol (29/11)
Xylose in DMM/methanol (25/15)
Xylose in DMM/methanol (15/25)
60
60
40
20
0
40
T = 150oC
20
0
O
O
250
300
350
400
450
500
250
300
350
400
450
500
Wavelength (nm)
Wavelength (nm)
15
10
5
15
10
5
Polymer
(c)
(d)
T = 160oC
T = 160oC
OH
OH
O
MLE in DMM, residenc time: 50 min
MLE in DMM, residenc time: 100 min
MLE in DMM/methanol, 50 min
MLE in DMM/methanol, 100 min
O
O
O
O
O
O
O
O
O
O
O
O
MMO
0
0
MOA
250
300
350
400
450
500
250
300
350
400
450
500
O
Wavelength (nm)
Wavelength (nm)
O
O
Figure 1 Constant energy (− 2800 cm−1) synchronous spectra of the
soluble polymers formed from the acidꢀcatalyzed conversion of xylose,
furfural and methyl levulinate (MLE) in DMM or DMM/methanol.
O
OH
O
O
O
Levulinic acid
Methyl levulinate
Scheme
2
The condensation of methyl levulinate in DMM. All the
Entry 20 to 28 in Table 1 shows the conversion of
xylose/glucose versus reaction time, catalysts and
electrophiles. The formation of levulinic acid/ester was
favored with the longer residence time (Entry 20). The Lewis
acid catalyst was not active for the conversion of xylose to
levulinic acid/ester (Entry 21), but was active for the
polymerization reactions (Figure S4). Combination of the Lewis
acid with A70 (Brønsted acid) did not improve the
performance (Entry 22 versus Entry 19). Acetalaldehyde as the
electrophile could not trigger the transformation of furfural to
HMF. In diethoxymethane (DEM)/water, the levulinate ester
produced was switched to ethyl levulinate (Entry 9), indicating
that the ethoxy group from DEM was transferred into the
compounds except the polymer were detected with GC-MS.
Levulinic acid or methyl levulinate has a ketone group and
active α-H, making them very active in the polymerization
reactions. It was found that the formation of levulinic
acid/ester from xylose (Figure S5) or furfural (Figure S6) was
always accompanied by the formation of methyl 3-methylene-
4-oxopentanoate (MMO) (Figure S1) and polymer (Figure S7
and S8), especially at the elevated reaction temperatures
where the yields of levulinic acid/ester were low. MMO was
identified by interpretation of its mass spectrum (Scheme S3
and S4), which was produced via the Aldol condensation
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between methyl levulinate and DMM. Other compounds catalyst with DMM/methanol as the reactant/solvent is
formed via similar routes were also identified (Scheme 2). required to achieve the direct conversion of the C5 sugars to
The formation of MMO and other condensation products levulinic acid/ester. In this method, DMM is the electrophile to
consumed the methyl levulinate produced and led to the transform furfural to HMF via the electrophilic substitution
polymer formation (Figure S7), which diminished the reactions. Methanol as the co-solvent/reactant played multiple
production of levulinic acid/ester from xylose or furfural. The critical roles, including: 1) promoting the electrophilic
abundance of MMO in DMM was three times higher than that substitution of furfural to produce HMF or the derivatives of
in DMM/methanol. Evidently, the presence of methanol HMF; 2) suppressing the polymerization reactions of the sugars
suppressed the Aldol condensation of levulinic acid/ester and in the acidic reaction medium; 3) suppressing the Aldol
preserved them in the reaction medium. This was further condensation of levulinic acid/ester with DMM. With the
verified by the experiments with methyl levulinate as the method developed, the cellulose-derived C6 sugars, the
starting reactant.
hemicelluloses-derived C5 sugars and the furans (furfural,
HMF) all can be converted to the same products, levulinic
acid/ester, via the same acid catalysis process. This drastically
enhances efficiency for the production of levulinic acid/ester
from biomass, the platform molecules for chemical diversity
and biofuels production.
This Project is supported by the Commonwealth of Australia
under the Australia-China Science and Research Fund as well
as Curtin University of Technology through the Curtin Research
Fellowship Scheme. This project received funding from ARENA
as part of ARENA's Emerging Renewables Program.
Figure 2 Conversion of methyl levulinate in DMM/water, DMM and
DMM/methanol at the reaction time of 50 and 100 min. Reaction
conditions: methyl levulinate: 1.8 g; A70: 3.6 g; DMM/co-solvent: 40
mL (volume ratio; 25: 15); T = 160oC.
Notes and references
1
J. P. M. Sanders, J. H. Clark, G. J. Harmsen, H. J. Heeres, J. J. Heijnen, S.
R. A. Kersten, W. P. M. Swaaij and J. A. Moulijn, Chem. Eng. Process.,
2012, 51, 117; D. M. Alonso, J. Q. Bond and J. A. Dumesic, Green Chem.,
2010, 12, 1493; G. W. Huber, S. Iborra and A. Corma, Chem. Rev., 2006,
106, 4044.
With methanol as the co-solvent, although MMO was still
formed (Table S2), the conversion of methyl levulinate was
much smaller (Figure 2). Evidently, the polymerization of
methyl levulinate was suppressed in the presence of
methanol. Aldol condensation was the main route for the
polymerization of methyl levulinate in DMM, leading to
formation of the polymers with the conjugated π-structures
and extended size (Figure 1c). Herein we demonstrated that
methanol could suppress the Aldol condensation reaction,
suppressing the polymer formation (Figure 1d) and preserving
levulinic acid/ester in the reaction medium.
2
Maria R. Galletti, C. Antonetti, V. D. Luise, D. Licursi and N. Nassi,
BioResources, 2012, 7, 1824.
3
4
X. Hu and C.ꢀZ. Li, Green Chem., 2011, 13, 1676.
C. Chatterjee, F. Pong and A. Sen, Green Chem., 2015, 17, 40; J. Song, L.
Wu, B. Zhou, H. Zhou, H. Fan, Y. Yang, Q. Meng and B. Han, Green
Chem., 2015,17, 1626.
5
G. Mazzotta, D. Gupta, B. Saha, A. K. Patra, A. Bhaumik and M. M. Abuꢀ
Omar, ChemSusChem, 2014, 7, 2342; S. Dias, M. Pillinger and A. A.
Valente, Appl. Catal. A: Gen., 2005, 285, 126.
6
7
J.ꢀP. Lange, E. Heide, J. Buijtenen and R. Price, ChemSusChem, 2012, 5,
150.
R. Weingarten, J. Cho, W. C. Conner, Jr. and G. W. Huber, Green Chem.,
2010, 12, 1423; C. GarcíaꢀSancho, I. Sádaba, R. MorenoꢀTost, J. Méridaꢀ
Robles, J. SantamaríaꢀGonzález, M. LópezꢀGranados and P. Mairelesꢀ
Torres, ChemSusChem, 2013, 6, 635.
Other reaction parameters on the conversion of
xylose/furfural in DMM/methanol were also investigated. The
mass transfer limitation was insignificant at stirring rate above
300 rpm (Figure S9). A70 has limited capacity to catalyse the
conversion of xylose with high loading (Figure S10), due to
deactivation induced by polymer formation (Figure S11 and
S12). The recycle tests with xylose (Figure S13) or furfural
(Figure S14) as starting reactant confirmed the deactivation of
A70. Both soluble polymer (Figure S15 and S16) and insoluble
polymer (Figure S17) were formed, which significantly reduced
acid density of A70 (Figure S18). The functionalities of the
8
K. Fulajtarova, T. Sotak, M. Hronec, I. Vavra, E. Dobrocka, M. Omastova,
Appl. Catal., A: Gen.2015, 502, 78.
9
M.M. Villaverde, N.M. Bertero, T.F. Garetto, A.J. Marchi, Catal. Today,
2013, 213, 87.
10
G. M. G. Maldonado, R. S. Assary, J. Dumesic and L. A. Curtiss, Energy
Environ. Sci., 2012, 5, 6981; J. P. Lange, W. D. Graaf and R. J. Haan,
ChemSusChem, 2009, 2, 437; X. Hu, Y. Song, L. Wu, M. Gholizadeh and
C.ꢀZ. Li, ACS Sustainable Chem. Eng., 2013, 1, 1593.
11
12
T. Deng, X. Cui, Y. Qi, Y. Wang, X. Hou and Y. Zhu, Chem. Commun.,
2012, 48, 5494; G. R. Akien, L. Qi and I. T. Horváth, Chem. Commun.,
2012, 48, 5850; W. Deng, M. Liu, Q. Zhang, X. Tan and Y. Wang, Chem.
Commun., 2010, 46, 2668.
X. Tong, Z. Liu, L. Yu and Y. Li, Chem. Commun., 2015, 51, 3674; M. A.
Harmer, A. Fan, A. Liauw and R. K. Kumar, Chem. Commun., 2009, 6610;
S. Dias, M. Pillinger and A. A. Valente, Appl. Catal. A: Gen., 2005, 285,
126.
soluble polymer include aromatic ring structures, the
α-β
unsaturated carbonyls and carbon double bonds (Figure S19).
The insoluble polymer has the similar functionalities (Figure
S17) and the similar thermal stability with A70 (Figure S20).
To summarize, a new route for the one-pot conversion of
biomass-derived C5 sugars and furans into levulinic acid/ester
has been demonstrated. The method is very simple. No
hydrogen or hydrogenation catalyst is needed. Only an acid
13
14
X. Hu, S. Wang, L. Wu, D. Dong, M. M. Hasan and C.ꢀZ. Li, Fuel Process.
Technol., 2014, 126, 315.
I. Zandvoort, Y. Wang, C. B. Rasrendra, E. R. H. Eck, P. C. A. Bruijnincx,
H. J. Heeres and B. M. Weckhuysen, ChemSusChem, 2013, 6, 1745.
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