MIL-100(Fe)-catalyzed efficient conversion of hexoses to lactic acid

Article abstract of DOI:10.1039/c6ra26469g

MIL-100(Fe) was used for the first time in the catalytic transformation of hexose sugars into lactic acid (LA). The as-synthesized MIL-100(Fe) was systematically characterized, and its superior morphological and textural properties were demonstrated to co

Full text of DOI:10.1039/c6ra26469g

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MIL-100(Fe)-catalyzed efficient conversion of
hexoses to lactic acid†
Cite this: RSC Adv., 2017, 7, 5621
*
Shan Huang, Kai-Li Yang, Xiao-Fang Liu, Hu Pan, Heng Zhang and Song Yang
MIL-100(Fe) was used for the first time in the catalytic transformation of hexose sugars into lactic acid (LA).
The as-synthesized MIL-100(Fe) was systematically characterized, and its superior morphological and
textural properties were demonstrated to contribute greatly to the pronounced catalytic performance in
fructose-to-LA conversion (up to 32% yield), as compared with other catalysts like Cu-BTC and MIL-
100(Cr). The effects of reaction conditions including temperature, reaction time, and substrate loading
were explored. In addition, MIL-100(Fe) could be easily reused for 4 cycles with no evident decrease in
catalytic activity.
Received 8th November 2016
Accepted 27th December 2016
DOI: 10.1039/c6ra26469g
www.rsc.org/advances
conversion of mono- and disaccharides to methyl lactate
(MLA) and LA at 160 ꢁC within 20 h, and acceptable amounts of
1. Introduction
LA (28% for sucrose and 27% for fructose) were formed in H2O
by using sucrose and fructose as substrate.11 Chambon et al.
employed Lewis acidic tungstated alumina (AlW) to catalyze
cellulose into LA with 27% yield at 190 ꢁC for 24 h, and
a moderate LA yield of 21% could be obtained from glucose at
190 ꢁC for 1 h.12 However, these solid catalysts are generally
not active enough for producing LA from sugars. Therefore,
research on the design and use of efficient Lewis acid catalysts
in selective transformation of hexose into LA is highly
desirable.
In virtue of the conspicuous advantages of large surface area,
extra-high porosity, adjustable pore size, structural diversity,
high thermal and chemical stability, and controllable compo-
sition with lots of coordinatively unsaturated metal sites (CUS),
metal–organic frameworks (MOFs) has attracted increasing
attention and been applied in various elds such as imaging,14
sensors,15 adsorption,16 separation,17 gas storage,18 drug
carrier,19 and heterogeneous catalysis.20–22 Among the Lewis
acidic metal–organic framework materials (e.g., chromium,23
copper,24 and zirconium carboxylates25), MIL-100(Fe) is an
attractive candidate in view that the precursor material, iron, is
much more abundant, cheap, nonhazardous and easy to get,
and that the quality and structure properties of MIL-100(Fe) are
spectacular and simple to prepare.26 The three-dimensional
crystalline iron(III) trimesate MIL-100(Fe) possesses two
Lignocellulosic biomass is considered to be a replacement for
fossil energy, and efficient catalytic conversions of renewable
lignocellulosic biomass to produce high value-added chemicals
and biofuels are a potential way to mitigate the rigorously
deteriorating pollution of the environment, the consumption of
fossil fuels and the attendant global warming.1–5 As a precursor
to produce biodegradable polylactic acid (PLA), LA, a high-
potential versatile biobased platform molecule, has been
widely employed in the food industry as well as the cosmetic
industry. It is also a remarkable molecule for the synthesis of
a wide range of attractive intermediates such as acrylic acid,
propylene glycol, 2,3-pentanedione, acetaldehyde, pyruvic acid,
1,2-propanediol and lactic acid esters.6 The annual demand for
LA is expected to increase to 6 ꢀ 105 tons by 2020.7
LA is generally produced via conventional fermentation of
carbohydrates.8 Nevertheless, this process suffers from low
space-time yields, and complicated and tedious separation
process with signicant amounts of salt wastes formed.
Therefore, alternative chemo-catalytic approaches toward LA
and alkyl lactates from renewable carbohydrates are of great
interest.9–13 Lewis acids were demonstrated to play an extremely
essential role in retro-aldol reaction, isomerization and 1,2-
hydride shi for the whole catalytic production of LA from
sugars.11 For instance, Holm et al. found that Lewis acidic
zeotype materials Sn-Beta exhibited good activity in the
˚
˚
different sets of mesoporous cages (25 A and 29 A in diameter)
˚
˚
with microporous windows (5.5 A and 8.6 A in diameter), which
is build up from trimers of iron octahedral sharing a common
vertex m3-O linked by the benzene-1,3,5-trimesic acid.26,28 The
Lewis acid sites are generated by removing the OHꢂ or Fꢂ
anions that coordinated with the iron octahedral.27,34 In recent
years, MIL-100(Fe) has been used as a Lewis acid catalyst to
show outstanding performance in organic synthesis.28–33
State Key Laboratory Breeding Base of Green Pesticide & Agricultural Bioengineering,
Key Laboratory of Green Pesticide
& Agricultural Bioengineering, Ministry of
Education, State-Local Joint Laboratory for Comprehensive Utilization of Biomass,
Center for Research & Development of Fine Chemicals, Guizhou University, Guiyang
550025, China. E-mail: jhzx.msm@gmail.com; Fax: +86-851-8829-2170; Tel: +86-
851-8829-2171
† Electronic supplementary information (ESI) available. See DOI:
10.1039/c6ra26469g
This journal is © The Royal Society of Chemistry 2017
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To the best of our knowledge, rare study has been conducted acid and H2O with the composition of 1.0 Fe0 : 0.67 1,3,5-
on the synthesis of LA from hexose catalyzed by MOFs. Herein, we BTC : 2.0 HF : 0.6 HNO3 : 277 H2O at 150 ꢁC for 12 h according
examined the catalytic performance of MIL-100(Fe), Cu-BTC and to the literature.34 Cu-BTC and MIL-100(Cr) were hydrother-
MIL-100(Cr) in the direct conversion of fructose to LA in H2O.
mally synthesized following the procedure described in the
previous literatures (see catalyst preparation and characteriza-
tion in ESI†).35,36
2. Experimental
2.1 Materials
The X-ray powder diffraction (XRD) patterns were obtained
on a XPD-6000 diffractometer using CuKa radiation (k ¼ 0.1541
nm) in a scanning range of 5–35ꢁ at a scanning rate of 1ꢁ minꢂ1
.
All the reagents were used as received without any further
purication. Fructose (99%), D(+)-glucose (AR), sucrose (AR), D-
(+)-cellobiose (98%), inulin, LA (99%), formic acid (FA), (HPLC
$ 98%), 5-hydroxymethylfurfural (HMF; 99%), CrO3 (99%, AR),
Cu(NO3)2$3H2O (99%, AR), Fe(NO3)3$9H2O (AR), iron powder
(98%), and hydrouoric acid (49% in water) were purchased
from Shanghai Aladdin Industrial Inc. 1,3,5-Benzenetricarbox-
ylic acid (H3BTC), methyl lactate (MLA; 98%), acetic acid (AA;
99.8%) and levulinic acid (LeA; 99%) were purchased from J & K
Scientic Ltd. Nitric acid (65%) and ethanol (AR grade) were
purchased from Chongqing Chuandong Chemical co., Ltd.
Deionized water was from Milli-Q Advantage A10 (USA) ultra-
pure water purication system.
The scanning electron microscope (SEM) observations were
performed on a ZEISS apparatus equipped with a eld emission
gun. The measurements of N2 adsorption were performed on
ꢁ
a Micromeritics ASAP 2020 apparatus at ꢂ196 C, prior to the
adsorption measurement, the sample was outgassed in vacuum
at 150 ꢁC for 12 h. The specic surface areas of the investigated
samples were calculated using the multiple-point Brunauer–
Emmett–Teller (BET) method in the relative pressure range of p/
p0 ¼ 0.05–0.20 and the total pore volumes were determined at
a relative pressure of 0.95. The pore size distribution curves
were determined from the adsorption isotherms by the Density
Functional Theory (DFT) method. The thermogravimetric
analysis (TGA) was performed on a NETZSCH STA 449 C
instrument from 35 to 600 ꢁC, using a heating rate of 10 ꢁC
minꢂ1 under a N2 ow (40 mL minꢂ1). The FT-IR spectra were
collected on a Nicolet 360 Fourier transform IR spectropho-
tometer in KBr disks at room temperature. The acid properties
of MIL-100(Fe) and other two MOFs were characterized by using
pyridine adsorption infrared spectroscopy recorded on Brooke
Tensor 27 Fourier infrared spectrometer. The sample was acti-
2.2 Analysis
LA, FA and AA were analyzed via an Agilent 1100 HPLC using an
Agilent TC-C18 column (4.6 mm ID ꢀ 250 mm) with 0.05 wt%
H3PO4 aqueous solution (A) and methanol (B) (VA : VB ¼ 90 : 10)
as eluent. The UV detector was set at a wavelength of 210 nm, the
columns were thermostatized at 30 ꢁC and the ow rate was set at
0.6 mL minꢂ1. For the detection of LeA, the mobile phase was
consisted of 0.05 wt% H3PO4 aqueous solution (C) and acetoni-
trile (D) (VC : VD ¼ 90 : 10). The UV detector was set at a wave-
length of 254 nm, the columns were thermostatized at 30 ꢁC and
the ow rate was set at 0.6 mL minꢂ1. For the detection of HMF,
the mobile phase was consisted of methanol (E) and H2O (F) (VE/
VF ¼ 65 : 35) at a ow rate of 1.0 mL minꢂ1. The UV detector was
set at a wavelength of 280 nm. For the HPLC analyses, 0.5 mL of
the reaction mixture was diluted to a total volume of 5.0 mL with
the eluent. The products were identied by UV (210 nm) detectors
by comparing them to the original samples. Sugars were analyzed
by Agilent 1100 HPLC tted with an Aminex HPX-87H column
(Bio-Rad, Richmond, CA) and a refractive index (RI) detector with
the mobile phase CH3CN (G) and H2O (H) (VG/VH ¼ 80 : 20) at
ꢁ
vated at 150 C for 3 h and then pressed into circular uniform
slices (15 mm diameter, 15 mg) in the self-supported disk
(without KBr) under the infrared lamp light with 12 KPa pres-
sure. The spectrum was recorded as background aer cooling
the tablet down to room temperature. Pyridine vapour was then
introduced into the cell. The amount of iron leaching was
determined by ICP-MS on a Vista Axial instrument (Varian of
USA).
2.4 Catalytic reactions
All experiments were carried out in a 25 mL Teon lined auto-
clave. For the conversion of sugar to LA, substrate (50 mg)
catalyst (50 mg) and 10 mL H2O were added into the reactor,
which was then placed into a preheated oil bath with magnetic
stirring at 190 ꢁC for 2 h. The reactor was all immersed in the oil
bath and the reaction time was started to record immediately.
Aer the reaction nished, the reactor was fast took out and
cooled rapidly by tap-water. Aerward, the catalyst was recov-
ered through centrifugation and the reaction liquid was ltered
with a 0.45 mm syringe lter, and then analyzed by HPLC.
For the sake of comparison, blank experiment without
catalyst and experiments with metal salt, Fe(NO3)3$9H2O, and
two Lewis acid MOFs materials (i.e., Cu-BTC and MIL-100(Cr))
were carried out. A number of recycling experiments were also
conducted to examine the catalyst stability. Aer each run, the
a ow rate of 1.0 mL minꢂ1
.
The conversion of sugar and LA yield were calculated
according to eqn (1) and (2), respectively.
X (sugar conversion, %) ¼ (mass of sugar converted/
mass of starting sugar) ꢀ 100%
(1)
(2)
Y (product yield, %) ¼ (mole of carbon in product/
mole of carbon in sugar) ꢀ 100%
2.3 Catalyst preparation and characterization
MIL-100(Fe) was synthesized hydrothermally by reacting of iron recovered solid was washed with ethanol to remove the adsor-
powder with H3BTC in the presence of hydrouoric acid, nitric bed organic species.
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3. Results and discussion
3.1 Catalyst characterization
The experimental XRD pattern of MIL-100(Fe) is illustrated in
Fig. 1. Correspondingly, the XRD patterns of MIL-100(Cr) and
Cu-BTC are displayed in Fig. S2.† It can be seen that the XRD
pattern of the prepared catalyst is in good agreement with the
simulated one, showing the successful preparation of MOFs.
The textural property of the synthesized MIL-100(Fe)
assessed by N2 adsorption isotherm is presented in Fig. 2. The
prepared MIL-100(Fe) gave a BET surface area of 1650 m2 gꢂ1
with a pore volume of 0.74 cm3 gꢂ1, and the pore size distri-
bution of MIL-100(Fe) estimated by using the DFT method
displayed two different pore sizes (about 1.9 and 2.2 nm,
respectively; Fig. S1†), suggesting that there are two types of
cages in the framework of MIL-100(Fe).
Fig. 3 TG curves of the synthesized MIL-100(Fe), MIL-100(Cr) and Cu-
BTC.
ꢁ
Fig. 3 reveals that the MIL-100(Fe) is stable up to 330 C, as
veried by TG analysis, and there are three weight loss
(about 41 wt%), is related to the decomposition of the H3BTC.
Similar TG curves of both MIL-100(Cr) and Cu-BTC are obtained
with MIL-100(Fe), MIL-100(Cr) is stable up to 300 ꢁC and Cu-
BTC is 250 ꢁC, respectively.
Fig. 4 shows the SEM image of MIL-100(Fe). The synthesized
MIL-100(Fe) is mainly octahedral in shape, and the particle is
ꢁ
processes between 35 and 600 C. The rst one (about 4 wt%)
ranging from 35 to 100 ꢁC is attributed to the desorption of free
water molecules inside the pores. The second weight loss (about
ꢁ
8 wt%) in the range of 100–330 C is water coordinated to the
iron trimers. The nal weight loss, between 330 and 530 ꢁC
Fig. 4 SEM image of the synthesized MIL-100(Fe).
Fig. 1 XRD patterns of synthesized and simulated MIL-100(Fe).
Fig. 2 N2 isotherm of the synthesized MIL-100(Fe).
Fig. 5 FT-IR spectrum of the synthesized MIL-100(Fe).
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uniform in size. Fig. 5 indicates the FT-IR spectrum of the
synthesized MIL-100(Fe). The band at 3445 cmꢂ1 was attributed
to –OH, 1385, 1450 and 1625 cmꢂ1 were n(C–O) stretching
vibration, n(–OH) exural vibration and n(C]O) stretching
vibration, and 762 and 712 cmꢂ1 were ngerprints assigned to
n(C–H) stretching vibration of benzene ring, respectively. There
is no peak at 1710–1720 cmꢂ1 assigned to the C]O stretching
vibration of H3BTC, indicating that the purication procedure
used here is particularly effective to remove residual H3BTC. On
the basis of the characterization results above (i.e., XRD, N2
adsorption, TGA, SEM and FT-IR), it can be concluded that MIL-
100(Fe) is successfully synthesized in this work.
3.2 Catalytic activity
Fig. 6 Influence of reaction temperature on the yield of LA. Reaction
conditions: fructose 0.05 g, MIL-100(Fe) 0.05 g, water 10 mL, 2 h.
3.2.1 Transformation of fructose into LA by different
catalysts. Catalytic conversion of fructose by using different
catalysts was carried out, and the results are shown in Table 1.
3% yield of LA was obtained without a catalyst.37 Comparison of
the blank control trial with the catalytic result of MIL-100(Fe)
illustrated that this MOF material showed good activity. In
contrast, only about 10% yield of LA was achieved over the
homogeneous iron salt, Fe(NO3)3.
pyridine adsorption infrared spectroscopy. Fig. S4† shows the
infrared spectra of pyridine adsorbed on those MOFs. The
intensity of the bands between 1000 and 1100 cmꢂ1, which
assigned to pyridine molecule chemisorbed on Lewis acid sites
of MIL-100(Fe),38 was much stronger than Cu-BTC and MIL-
100(Cr), illustrating that the concentration of Lewis acid
centers in MIL-100(Fe) was higher than that of other two
materials. Thus, the best performance of the Lewis acid MIL-
100(Fe) could be expected.
3.2.2 Inuence of reaction temperature on the production
of LA. In subsequent tests, fructose was used as substrate with
MIL-100(Fe) as catalyst. Reaction temperature was an important
factor (Fig. 6). When the reaction temperature was increased
from 150 to 210 ꢁC, the conversion of fructose was improved
sharply from 37% to 89%. The yield of LA increased with the
extension of reaction temperature and reached the highest yield
(33%) at 210 ꢁC, while the yields of FA, LeA and AA were as well
increased with increasing temperature. Because the yield of LA
did not increase markedly above 190 ꢁC (32%), the reaction
temperature was xed at 190 ꢁC in the following study.
3.2.3 Effect of reaction time on the conversion of fructose
to LA. The effect of reaction time on production of LA from
fructose was further explored (Fig. 7). The results show that
prolonging the reaction time from 0.5 to 2 h, MIL-100(Fe) could
give 14% and 32% yields of LA at 70% and 87% conversion,
respectively. When further extending the time to 3.5 h and 5 h,
no increase in LA yield was observed but a slight increase of
fructose conversion, suggesting that by-products were formed
more and more. Thus, 2 h was selected as the optimal time for
the catalytic reaction.
From Table 1, it can be seen that LA, together with HMF, LeA,
AA, and FA, is the product in this reaction system. MIL-100(Fe)
is the most effective catalyst among the examined Lewis acid
materials, giving LA yield of 32%, HMF of 17%, FA of 9%, AA of
7%, and LeA of 6%. The good catalytic results of MIL-100(Fe)
could never be existed without its excellent morphological
characteristics and textural properties. Fig. 2 shows that MIL-
100(Fe) possesses higher specic surface area (SBET ¼ 1650 m2
gꢂ1) than MIL-100(Cr) (SBET ¼ 1330 m2 gꢂ1
)
36 and Cu-BTC (SBET
¼ 1223 m2 gꢂ1).35 Besides, the thermal stability is also checked.
It can be observed that the thermal stability of MIL-100(Fe) is
better than that of other two materials (Fig. 3), which is in
agreement with the catalytic results (i.e., 20% LA yield for MIL-
100(Cr), and 18% for Cu-BTC).
To gure out the intrinsic reason for the activity sequence of
the three MOFs, their acid properties were further compared.
The metal cations that are integral to the framework could be
made catalytically-active by removal of their solvent ligands to
a vacant coordination site as a Lewis acid. In this work, we
characterized the acid properties of the three MOFs by using
Table 1 Conversion of fructose into LA catalyzed by various catalystsa
Yield (%)
3.2.4 Results of different fructose amount on the produc-
tion of LA. Fig. 8 showed that the optimum amount of fructose
was 0.05 g, further increasing the amount of fructose from 0.05
to 0.2 g, the yield of LA only decreased slightly. By that data, we
could conclude that MIL-100(Fe) used in this reaction main-
tained active at high concentrations of fructose. Hence, the
initial substrate amount was xed at 0.05 g.
Entry Catalyst
Conv. (%) LA HMF FA AA LeA Total
1
2
3
4
5
No catalyst
Fe(NO3)3
MIL-100(Fe) 87
Cu-BTC 73
MIL-100(Cr) 76
39
68
3
10
11
9
7
3
9
7
5
2
3
26
51
71
60
61
16 13
32 17
18 26
20 28
7
3
5
6
6
3
a
Reaction conditions: fructose 0.05 g, catalyst 0.05 g, H2O 10 mL,
3.2.5 Conversions of different sugars into LA catalyzed by
MIL-100(Fe). The hydrothermal conversions of different sugars
190 ꢁC, 2 h.
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Fig.
9
Conversion of different substrates using MIL-100(Fe) as
a catalyst. Reaction conditions: substrate 0.05 g, catalyst 0.05 g, H2O
10 mL, 190 ꢁC, 2 h.
Fig. 7 Influence of reaction time on the yield of LA. Reaction condi-
tions: fructose 0.05 g, MIL-100(Fe) 0.05 g, water 10 mL, 190 ꢁC.
Fig. 10 Reusability of MIL-100(Fe) for the conversion of fructose to LA.
Reaction conditions: fructose 0.05 g, MIL-100(Fe) 0.05 g, water 10 mL,
190 ꢁC, 2 h.
Fig. 8 Conversion of fructose into LA with different initial amount of
fructose. Reaction conditions: MIL-100(Fe) 0.05 g, water 10 mL,
190 ꢁC, 2 h.
followed by washing with ethanol to remove adsorbed
compounds and then dried at 80 ꢁC before the next cycle. There
was still 20% yield of LA when the MIL-100(Fe) was reused four
times. The general causes of the apparent catalyst deactivation
fall into two respects. Firstly, the accelerated deposition of some
oligomeric products in pores that resulted in the blocking of the
active sites and partial structural changes within the catalyst.21
To verify this, the recovered catalyst was characterized by N2
adsorption–desorption, XRD, and FT-IR. As shown in Fig. S5
and S6,† it can be seen that the XRD pattern and FT-IR spectra
of the used catalyst did not show remarkably changes compared
to the fresh MIL-100(Fe), illustrating that the framework struc-
ture of this MOF material was maintained. From Fig. S7,† there
was a reduction of the BET surface area and pore volume, which
might hinder the mass transport for producing LA. Secondly,
a small quantity of active sites were leached out from the reused
catalyst (aer it being used 4 times). We found some H3BTC in
the ltrate (of the fourth cycle) by HPLC, explaining that the
catalyst released gradually trimesic acid. And the loss of the
were also investigated by using MIL-100(Fe) as catalyst. It is easy
to form HMF and LeA from fructose catalyzed by Brønsted
acids,39,40 while Lewis acids are demonstrated to catalyze retro-
aldol reaction, isomerization and 1,2-hydride shi for fructose
being converted to lactic acid.11 The results presented in Fig. 9
show that there is 20% yield of LA with glucose as substrate, and
the yields of HMF and LeA are less than LA, which further
proved the view above. When using disaccharide (e.g., sucrose
and cellobiose) and polysaccharide (e.g., inulin) as substrate,
a LA yield of 25%, 10% and 22% was achieved, respectively. In
addition, changing the solvent from water to methanol led to
the formation of MLA (Table S1†). For fructose, a 33% yield of
MLA were obtained (entry 4).
3.3 Reuse of catalyst
The reusability of catalyst in the hydrothermal conversion of
fructose was also evaluated (Fig. 10). In a forth-cycle experi-
ment, the catalyst was separated by simple centrifugation
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original metal–organic linker bond could lead to leaching of
some metal ion from the MOF.41 ICP-MS analysis showed the
presence of 3.03 ppm of Fe in the ltrate of the fourth cycle,
which means that the reused catalyst released some iron. These
two changes led to a slight decrease in acidity density of catalyst,
which further resulted in lower selectivity to LA. Besides, from
the result of NH3-TPD in Fig. S8,† the acidity of the recovered
8 F. de Clippel, M. Dusselier, R. Van Rompaey, P. Vanelderen,
J. Dijkmans, E. Makshina, L. Giebeler, S. Oswald,
G. V. Baron, J. F. M. Denayer, P. P. Pescarmona,
P. A. Jacobs and B. F. Sels, J. Am. Chem. Soc., 2012, 134, 10089.
9 Q. Guo, F. T. Fan, E. A. Pidko, W. N. P. van der Graaff,
Z. C. Feng, C. Li and E. J. M. Hensen, ChemSusChem, 2013,
6, 1352.
catalyst decreased slightly, which also led to lower selectivity 10 F. F. Wang, C. L. Liu and W. S. Dong, Green Chem., 2013, 15,
toward lactic acid. In order to better reuse the catalyst, we 2091.
further employed a simple method for regeneration of the 11 M. S. Holm, S. Saravanamurugan and E. Taarning, Science,
recovered catalyst, referring to a protocol reported by Han et al. 2010, 328, 602.
(see ESI†).42 Activity evaluation revealed that the regenerated 12 F. Chambon, F. Rataboul, C. Pinel, A. Cabiac, E. Guillon and
MIL-100(Fe) regained the catalytic activity (28% yield of LA). N. Essayem, Appl. Catal., B, 2011, 105, 171.
Even though this catalyst couldn't keep completely stable, it still 13 L. S. Yang, X. K. Yang, E. Tian, V. Vattipalli, W. Fan and
made MIL-100(Fe) an alternative catalyst for the conversion of
fructose to LA.
H. F. Lin, J. Catal., 2016, 333, 207.
14 K. M. L. Taylor-Pashow, J. D. Rocca, Z. G. Xie, S. Tran and
W. B. Lin, J. Am. Chem. Soc., 2009, 131, 14261.
15 Y. Q. Xiao, Y. J. Cui, Q. Zheng, S. C. Xiang, G. D. Qian and
B. L. Chen, Chem. Commun., 2010, 46, 5503.
4. Conclusions
ˇ
16 A. Zukal, M. Opanasenko, M. Rubes, P. Nachtigall and
In summary, the as-synthesized MIL-100(Fe) was used for the
rst time as Lewis acid catalyst for catalytic transformation of
sugars to LA, and showed satisfactory performance. A high yield
of LA, up to 32%, was produced from fructose with MIL-100(Fe)
in H2O at 190 ꢁC for 2 h. In order to better understand the
relationship between the structure properties and the catalytic
performance, the catalytic activities of Cu-BTC and MIL-100(Cr)
were also tested and compared. The results showed that both
materials are not as active as MIL-100(Fe). The metal nature in
the framework, specic surface area, stability and Lewis acid
properties of these MOFs were demonstrated to inuence their
catalytic activities. Furthermore, the MIL-100(Fe) could be easily
reused for 4 cycles. Therefore, MOFs are very promising mate-
rials for biomass conversion, especially for LA production.
J. Jagiello, Catal. Today, 2015, 243, 69.
17 S. L. Qiu, M. Xue and G. S. Zhu, Chem. Soc. Rev., 2014, 43,
6116.
18 J. A. Mason, M. Veenstra and J. R. Long, Chem. Sci., 2014, 5,
32.
19 S. Rojas, F. J. Carmona, C. R. Maldonado, E. Barea and
J. A. R. Navarro, New J. Chem., 2016, 40, 5690.
20 A. Corma, H. Garcıa and F. X. L. i Xamena, Chem. Rev., 2010,
´
110, 4606.
21 X. F. Liu, H. Li, H. Zhang, H. Pan, S. Huang, K. L. Yang and
S. Yang, RSC Adv., 2016, 6, 90232.
22 A. Herbst and C. Janiak, New J. Chem., 2016, 40, 7958.
23 L. Mitchell, B. Gonzalez-Santiago, J. P. S. Mowat, M. E. Gunn,
P. Williamson, N. Acerbi, M. L. Clarke and P. A. Wright,
Catal. Sci. Technol., 2013, 3, 606.
´
Acknowledgements
24 L. Alaerts, E. Seguin, H. Poelman, F. Thibault-Starzyk,
P. A. Jacobs and D. E. De Vos, Chem.–Eur. J., 2006, 12, 7353.
25 T. L. H. Doan, T. Q. Dao, H. N. Tran, P. H. Tran and T. N. Le,
Dalton Trans., 2016, 45, 7875.
This work was nancially supported by the National Natural
Science Foundation of China (No. 21576059 & 21666008), the
Key Technologies R & D Program (No. 2014BAD23B01), and the
Innovation Fund for Graduate Students of Guizhou University
(No. 2016075).
´
26 L. Mitchell, P. Williamson, B. Ehrlichova, A. E. Anderson,
V. R. Seymour, S. E. Ashbrook, N. Acerbi, L. M. Daniels,
R. I. Walton, M. L. Clarke and P. A. Wright, Chem.–Eur. J.,
2014, 20, 17185.
´
27 P. Horcajada, S. Surble, C. Serre, D. Y. Hong, Y. K. Seo,
References
`
´
J. S. Chang, J. M. Greneche, I. Margiolaki and G. Ferey,
Chem. Commun., 2007, 2820.
28 A. Dhakshinamoorthy, M. Alvaro, Y. K. Hwang, Y. K. Seo,
1 K. Yan, G. S. Wu, T. Laeur and C. Jarvis, Renewable
Sustainable Energy Rev., 2014, 38, 663.
2 K. Yan, C. Jarvis, J. Gu and Y. Yan, Renewable Sustainable
Energy Rev., 2015, 51, 986.
A. Corma and H. Garcia, Dalton Trans., 2011, 40, 10719.
ˇ
ˇ
´
29 L. Kurrtova, Y. K. Seo, Y. K. Hwang, J. S. Chang and J. Cejka,
¨
3 C. Zhao, T. Bruck and J. A. Lercher, Green Chem., 2013, 15,
Catal. Today, 2012, 179, 85.
1720.
30 A. Dhakshinamoorthy, M. Alvaro, H. Chevreau,
P. Horcajada, T. Devic, C. Serre and H. Garcia, Catal. Sci.
Technol., 2012, 2, 324.
4 H. Li, P. S. Bhadury, A. Riisager and S. Yang, Catal. Sci.
Technol., 2014, 4, 4138.
5 H. Li, Z. Fang and S. Yang, ChemPlusChem, 2016, 81, 135.
6 P. Gallezot, Chem. Soc. Rev., 2012, 41, 1538.
7 M. Dusselier, P. Van Wouwe, A. Dewaele, E. Makshina and
B. F. Sels, Energy Environ. Sci., 2013, 6, 1415.
31 F. Vermoortele, R. Ameloot, L. Alaerts, R. Matthessen,
B. Carlier, E. V. Ramos Fernandez, J. Gascon, F. Kapteijn
and D. E. De Vos, J. Mater. Chem., 2012, 22, 10313.
5626 | RSC Adv., 2017, 7, 5621–5627
This journal is © The Royal Society of Chemistry 2017

View Article Online
Paper
RSC Advances
´
32 L. Mitchell, P. Williamson, B. Ehrlichova, A. E. Anderson, 37 X. Y. Yan, F. M. Jin, K. Tohji, T. Moriya and H. Enomoto, J.
V. R. Seymour, S. E. Ashbrook, N. Acerbi, L. M. Daniels, Mater. Sci., 2007, 42, 995.
R. I. Walton, M. L. Clarke and P. A. Wright, Chem.–Eur. J., 38 H. Leclerc, A. Vimont, J. C. Lavalley, M. Daturi,
´
2014, 20, 17185.
A. D. Wiersum, P. L. Llwellyn, P. Horcajada, G. Ferey and
33 F. M. Zhang, J. Shi, Y. Jin, Y. H. Fu, Y. J. Zhong and
W. D. Zhu, Chem. Eng. J., 2015, 259, 183.
34 J. W. Yoon, Y. K. Seo, Y. K. Hwang, J. S. Chang, H. Leclerc,
S. Wuttke, P. Bazin, A. Vimont, M. Daturi, E. Bloch,
C. Serre, Phys. Chem. Chem. Phys., 2011, 13, 11748.
39 V. Choudhary, S. H. Mushrif, C. Ho, A. Anderko,
V. Nikolakis, N. S. Marinkovic, A. I. Frenkel, S. I. Sandler
and D. G. Vlachos, J. Am. Chem. Soc., 2013, 135, 3997.
`
´
P. L. Llewellyn, C. Serre, P. Horcajada, J. M. Greneche, 40 Y. J. Pagan-Torres, T. F. Wang, J. M. R. Gallo, B. H. Shanks
´
A. E. Rodrigues and G. Ferey, Angew. Chem., Int. Ed., 2010,
49, 5949.
and J. A. Dumesic, ACS Catal., 2012, 2, 930.
41 S. Das, D. E. Johnston and S. Das, CrystEngComm, 2012, 14,
6136.
35 M. Hartmann, S. Kunz, D. Himsl and O. Tangermann,
Langmuir, 2008, 24, 8634.
42 S. Han and M. S. Lah, Cryst. Growth Des., 2015, 15, 5568.
36 M. Wickenheisser, F. Jeremias, S. K. Henninger and
C. Janiak, Inorg. Chim. Acta, 2013, 407, 145.
This journal is © The Royal Society of Chemistry 2017
RSC Adv., 2017, 7, 5621–5627 | 5627