A tannin-derived zirconium-containing porous hybrid for efficient Meerwein-Ponndorf-Verley reduction under mild conditions

Article abstract of DOI:10.1039/c9gc03393a

Both the use of renewable natural sources to prepare catalytic materials and the Meerwein-Ponndorf-Verley (MPV) reduction for carbonyl compounds are very attractive topics in catalysis. In this study, tannins were simply assembled with zirconium in water for the scalable preparation of a heterogeneous zirconium-tannin hybrid catalyst (Zr-tannin). Various characterizations demonstrated the formation of robust porous inorganic-organic frameworks and strong Lewis acid-base sites in Zr-tannin. The cooperative effect of these acid-base sites and the abundant porosity endowed Zr-tannin with a remarkable catalytic performance for the MPV reduction of a broad range of carbonyl compounds to alcohols with 2-propanol under mild conditions. Moreover, Zr-tannin exhibited good recyclability for at least five reaction cycles. This novel strategy using tannins as the raw materials to construct heterogeneous catalytic materials may have a huge potential for green chemical synthesis due to low cost, nontoxicity, and sustainability.

Full text of DOI:10.1039/c9gc03393a

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A tannin-derived zirconium-containing porous
hybrid for efficient Meerwein–Ponndorf–Verley
reduction under mild conditions†
Cite this: Green Chem., 2020, 22,
180
Yan Leng, * Langchen Shi, Shengyu Du, Jiusheng Jiang and Pingping Jiang
Both the use of renewable natural sources to prepare catalytic materials and the Meerwein–Ponndorf–
Verley (MPV) reduction for carbonyl compounds are very attractive topics in catalysis. In this study, tannins
were simply assembled with zirconium in water for the scalable preparation of a heterogeneous zirco-
nium–tannin hybrid catalyst (Zr-tannin). Various characterizations demonstrated the formation of robust
porous inorganic–organic frameworks and strong Lewis acid–base sites in Zr-tannin. The cooperative
effect of these acid–base sites and the abundant porosity endowed Zr-tannin with a remarkable catalytic
performance for the MPV reduction of a broad range of carbonyl compounds to alcohols with 2-propanol
under mild conditions. Moreover, Zr-tannin exhibited good recyclability for at least five reaction cycles.
This novel strategy using tannins as the raw materials to construct heterogeneous catalytic materials may
have a huge potential for green chemical synthesis due to low cost, nontoxicity, and sustainability.
Received 29th September 2019,
Accepted 20th November 2019
DOI: 10.1039/c9gc03393a
rsc.li/greenchem
with various metal ions is able to generate active solid catalysts
for heterogeneous catalysis.21–24 Through this method, several
Introduction
The Meerwein–Ponndorf–Verley (MPV) reaction is an ideal metal-based organic hybrids like Zr-LS, Zr-PhyA, and FDCA-Hf
reduction technique for carbonyl compounds because of using have been developed and used as solid catalysts for MPV
abundant and safe secondary alcohols as H-donor instead of reduction.25–32 The results indicate that via acid–base coopera-
dangerous gaseous hydrogen.1–3 Typically, the selective hydro- tive catalysis between metal ions and organic compounds,
genation of α,β-unsaturated aldehydes is of great importance high activity and selectivity can be achieved. Inspired by these
in the production of unsaturated alcohols, which have been useful examples, also taking into account that the diversity of
widely used in flavouring, perfume, and pharmaceutical natural compounds provides many possibilities for improving
industries.4,5 During the past decade, diverse catalysts based the catalytic performance,25,28,29,33 our attention was focused
on metal oxides, metal alloys, hydroxides, metal–organic on the construction of efficient Zr-containing solid catalysts
frameworks (MOF), and zeolites have been employed for MPV from natural resources for MPV reduction.
reductions.6–12 Among these catalysts, zirconium (Zr)-contain-
Tannins obtained from the seeds and barks of plants are
ing catalysts have been proven to be very effective for the abundant biomass fractions in nature, which have been widely
reduction of carbonyl compounds.13–17 However, most of them used in medicine, food, organic synthesis, and polymeric
often suffer from expensive raw materials, complex preparation materials.34–37 Especially, due to the presence of abundant
processes, harsh reaction conditions (high reaction tempera- phenolic hydroxy (Ar–OH) groups, tannins can easily coordi-
tures or long reaction times), and poor selectivity and stability. nate with metal ions to form insoluble M–tannin
Therefore, the development of cost-effective, sustainable, and hybrids.21,36,38–40 This unique feature makes tannins an ideal
more efficient Zr-based catalysts for MPV reduction is desirable adsorbent in the field of water treatment.35,41 Despite the versa-
and imperative.
tile applications of tannins in many functional materials and
The use of renewable natural sources to synthesize func- environmental areas, quite surprisingly, their use as a building
tional materials has been recognized as a crucial research block for metal–organic hybrid catalyst synthesis has been
area.18–20 The assembly of natural compounds, such as poly- seldom explored. Herein, we prepared a Zr-tannin porous cata-
phenols, lignins, porphyrins, phytic acid, and furan derivatives lyst simply by the chelation of Zr4+ and tannins. The Zr-tannin
was explored to be a highly active and stable solid catalyst for
the MPV reduction of various carbonyl compounds to alcohols
School of Chemical and Material Engineering, Jiangnan University, Lihu Road 1800#,
with 2-propanol (2-PrOH) as the hydrogen source. Extensive
Wuxi 214122, Jiangsu, China. E-mail: yanleng@jiangnan.edu.cn
characterizations were performed to investigate the relationship
†Electronic supplementary information (ESI) available. See DOI: 10.1039/
between the catalytic active sites and its catalytic performance.
c9gc03393a
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The results demonstrated that the porous organic–inorganic for Lewis acid sites, respectively; R stands for the radius of the
networks and acid–base synergistic sites in Zr-tannin may be self-supported disk; W stands for the sample weight.
responsible for the excellent catalytic performance.
Preparation of catalysts
In a typical procedure for Zr-tannin preparation, tannins
(1.0 g, 0.6 mmol) were dissolved in 30 mL deionized water in a
100 mL round-bottomed flask. The aqueous solution was
heated to 80 °C in an oil bath, and then an aqueous solution
Experimental section
Reagents and analyses
All chemicals were of analytical grade and used as received.
Thermogravimetric (TG) analysis was performed using a
STA409 instrument at a heating rate of 10 °C min−1 in nitrogen
flow from 30 to 800 °C. Fourier infrared (FT-IR) spectra were
recorded on a Nicolet 360 FT-IR instrument (KBr. discs) in the
4000–400 cm−1 region. Diffuse reflectance UV–vis spectra of
solid samples were obtained on an UV-2550 spectrophoto-
meter using barium sulfate as background. The nitrogen
adsorption/desorption isotherms and pore size distribution
curves were measured at the temperature of liquid nitrogen
(77 K) using a BELSORP-MINI analyzer. The element distri-
bution was characterized by Hitachi S-4800 field emission
scanning electron microscope coupled with an energy-disper-
sive X-ray spectrometer. The Zr content in Zr-tannin was
measured using a Jarrell-Ash 1100 ICP-AES spectrometer. X-ray
photoelectron spectroscopy (XPS) was conducted on a PHI
5000 Versa Probe X-ray photoelectron spectrometer equipped
with Al Kα radiation (1486.6 eV). X-ray diffraction (XRD) pat-
terns were collected on a Bruker D8 Advance powder diffract-
ometer using Ni-filtered Cu/Kα radiation. Water repellency was
tested by the contact angle of the substrate droplet using a
contact angle meter of OCA 40. The acidity and basicity of the
samples were determined through temperature-programmed
desorption of NH3-TPD and CO2-TPD by a Micromeritics Bel
Cata II equipment. The sample was firstly degassed under
flowing He at 150 °C for 2 h. After the sample was cooled to
ambient temperature, 10 vol% CO2 or NH3 in Ar (50 mL
min−1) was adsorbed onto the solid sample at 50 °C for
60 min, followed by purging with He, and then the mass
signals were recorded by performing CO2 or NH3 desorption
from 50 °C to 250 °C. The Lewis and Brønsted acid sites of Zr-
tannin were measured by pyridine adsorption FT-IR fitted with
a Bruker VERTEX V70v system in the wavenumber range of
1400–1700 cm−1. The oven-dried sample (25 mg) was pressed
into a 13 mm self-supported wafer and activated in the IR cell
at 150 °C for 3 h. After it was cooled to room temperature, the
sample was contacted with pyridine vapor under vacuum for
1 h, which was followed by the evacuation of excess pyridine.
Then, the cell was kept in a vacuum oven at 150 °C/250 °C for
1 h to remove the physisorbed pyridine. Based on the following
equations, the concentration of Brønsted (CB (μmmol g−1)) and
Lewis acid (CL (μmmol g−1)) sites was calculated.16,42
of ZrCl4 (1.5 g ZrCl4 in 20 mL deionized water) was added
dropwise into it. The milky white mixture was stirred at 80 °C
for 12 h. The thus obtained solid was filtered and washed with
water several times, and subsequently dried in a vacuum at
70 °C overnight to give the final catalyst (Zr-tannin) with a
weight of about 0.85 g.
Catalytic tests
The MPV reduction of various carbonyl compounds using
2-PrOH as hydrogen-donor was carried out in a 35 mL pressure
tube. In a typical reaction procedure, furfural (1 mmol),
2-PrOH (10 mL), and the catalyst (0.1 g) were added into the
reactor and tightly sealed, and it was followed by heating to
80 °C. After magnetically stirring for 3 h, the solid catalyst was
removed by centrifugation and the liquid was quantitatively
analyzed by gas chromatography. The recovered catalyst could
be directly reused for the next cycle under identical reaction
conditions. In the leaching experiment, the catalyst was fil-
tered out form the reaction system after reacting for 60 min.
Then, the reaction was allowed to proceed for another 120 min
without the catalyst. The Zr leached into the reaction solution
was determined by ICP-AES, and the recovered catalyst was
analyzed by FT-IR.
Results and discussion
The fabrication process for Zr-tannin only involves a facile and
nontoxic one-step assembly synthesis in water (Scheme 1).
Tannins dissolved in water and coordinated rapidly with Zr4+
to form insoluble white precipitates (Zr-tannin) (Fig. S1†),
which were then filtered out, dried, and extensively character-
ized by SEM, FT-IR, XRD, N2 adsorption–desorption analysis,
ICP-AES, and TGA. The SEM image of Zr-tannin presents an
amorphous connected nanoparticle structure (Fig. 1A), and
the EDS mapping images demonstrate the homogeneous dis-
persion of Zr, C, and O elements throughout the Zr-tannin
hybrid (Fig. 1B). The XRD pattern of ZrCl4 exhibits clear diffr-
action peaks, but all these peaks have disappeared for Zr-
tannin (Fig. 1C), suggesting the irregular connectivity between
Zr4+ and tannins and the amorphous structure of Zr-tannin,
which is unlike ZrO2 with high crystallinity (Fig. S2†). The Zr
content in Zr-tannin was determined to be 22.3 wt% based on
the ICP-AES result, indicating a high load capacity of tannins
for metal ions. The TG profile indicated that Zr-tannin was
CB ðμmol gꢀ1Þ ¼ ð1:88 ꢁ IAB ꢁ R2Þ=W
CL ðμmol gꢀ1Þ ¼ ð1:42 ꢁ IAL ꢁ R2Þ=W
where IAB and IAL stand for the absorbance peak area at stable up to 250 °C (Fig. S3†). In addition, it was observed to
1450 cm−1 for Brønsted acid sites and peak area at 1540 cm−1 be insoluble in nonpolar and most polar solvents. These pro-
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Scheme 1 The preparation process of Zr-tannin using tannin as the building block and its plausible structure.
The FT-IR spectrum of tannins displayed the typical
vibration peaks for –Ar–OH bending (1307 cm−1), –C–O–
stretching (1186 cm−1, 1022 cm−1), and aromatic CvC stretch-
ing (1604 cm−1). Notably, for Zr-tannin, the vibrations at
1307 cm−1, 1186 cm−1, and 1022 cm−1 shifted to higher wave-
numbers of 1353 cm−1, 1197 cm−1, 1060 cm−1, respectively,
and the intensity of the band for aromatic CvC was remark-
ably decreased as compared with that of tannins (Fig. 1E). The
observations indicated the possible coordination between Zr4+
and –Ar–OH that caused the formation of –Ar–O2–Zr–O2–Ar–
frameworks. UV–vis spectroscopy was further performed to
confirm the coordination between Zr4+ and tannins (Fig. 1F).
Tannins exhibited absorption between 250 and 450 nm with a
maximum at 350 nm. In the case of Zr-tannin, these absorp-
tion bands were blue shifted with the maximum absorption
peak at 280 nm.
Catalytic performance
For the initial catalytic tests, we selected the MPV reduction of
furfural (FF) to furfuryl alcohol (FA) with 2-PrOH as the probe
reaction to study the catalytic performance of Zr-tannin and
control catalysts at 80 °C (Fig. 2A). The reaction did not
proceed at all without a catalyst or with tannins as the catalyst.
When Zr-tannin was used as the catalyst, a solid–liquid hetero-
geneous catalysis was observed and a high conversion of
96.2% with 95.0% selectivity was achieved. Even with a lower
reaction temperature of 70 °C or less catalyst amount of 80 mg,
considerable activity (conversion >70%) was obtained
(Fig. S4†). In contrast, ZrCl4 and ZrOCl2 induced a homo-
geneous system but caused low conversions of about ∼5%–6%
with ∼23%–25% selectivity. ZrO2 and Zr(C5H7O4)4 presented
slightly higher conversions (∼25%–35%) but caused very low
selectivity (∼1%–3%). MOFs are a class of popular catalytic
materials that have been demonstrated to be highly active in
many organic transformations.43–45 Accordingly, two common
Zr-based MOFs (UiO-66 and UiO-66-(OH)2 were prepared by
assembling benzene dicarboxylic acid and 2,5-dihydroxyter-
ephthalic acid46 and used as control catalysts for the reduction
Fig. 1 (A) SEM image and (B) EDS mapping images of Zr-tannin; (C)
XRD patterns of ZrCl4 and Zr-tannin; (D) N2 adsorption/desorption iso-
therms of Zr-tannin; (E) FT-IR spectra and (F) UV–vis spectra of tannin
and Zr-tannin.
perties enable Zr-tannin to be a solid catalyst in liquid-phase
reactions.
The building block tannin is a nonporous material. In con-
trast, the N2 adsorption/desorption isotherms of Zr-tannin dis-
played a IV-type isotherm with an obvious H3-hysteresis loop
(Fig. 1D), indicating that Zr-tannin is a mesoporous material.
The specific surface area and pore volume were measured to be
162 m2 g−1 and 0.635 cm3 g−1, respectively. This result suggests
that the assembly process between tannins and Zr4+ can
promote the formation of porous organic–inorganic networks.
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(Table S1†). The catalytic activity and selectivity of Zr-tannin
are much higher than those of FDCA-Hf, Mn-NCA-700, Fe-L1/
C-800, and NiO(P)-300. Zr-Based catalysts (such as Zr-PW,
PhP-Zr, Zr-GA, Zr-PN, Zr-RSL, Zr-PhyA, Zr-LS, and Zr-HAs) can
catalyze MPV reductions under milder conditions (80–120 °C).
Compared with them, not only is our Zr-tannin comparable in
activity, selectivity, and reusability, but also the preparation of
the present catalyst is much simpler.
Delighted by the excellent performance of Zr-tannin for the
MPV reduction of FF, we further investigated the catalytic
activity of Zr-tannin for other carbonyl compounds (Table 1).
As can be seen, Zr-tannin exhibited good activity and selecti-
vity toward biomass-based carbonyl compounds, such as
5-methylfurfural and cinnamaldehyde, showing more than
90% conversions with higher than 95% selectivity to the
corresponding alcohols (entries 2 and 3). Under proper rising
reaction temperature (80–120 °C), other commercial carbonyl
compounds, including benzaldehyde, salicylaldehyde, 4-hydro-
xybenzaldehyde, cyclohexanone, crotonaldehyde, and propanal
were also successfully converted into the corresponding alco-
Fig. 2 (A) The catalytic performance of various catalysts for the MPV
reduction of FF to FA with 2-PrOH; (B) the product distribution during
the MPV reduction over Zr-tannin; (C) the reusability of Zr-tannin for the hols with both high conversions and selectivity (entries 4–9).
MPV reduction of FF. Reaction conditions: Furfural 1 mmol, 2-PrOH
10 mL, Zr-tannin 100 mg, 80 °C, 3 h.
In the case of acetophenone and ethyl levulinate, due to their
higher electron density or steric hindrance, a higher reaction
temperature of 150 °C and relatively longer reaction times
(8–14 h) were needed to obtain satisfactory activity (entries 10
of FF. As can be seen, UiO-66 and UiO-66-(OH)2 gave 9.2% con- and 11). The above results indicate that the Zr-tannin hybrid
version with 34.1% selectivity and 23.2% conversion with 8.3% was a highly versatile catalyst for the MPV reduction of a wide
selectivity, respectively, which were much lower than that of scope of substrates.
Zr-tannin, indicating the superior performance of Zr-tannin
hybrid.
The time course of FF reduction over Zr-tannin was Understanding the catalytic
recorded at 80 °C (Fig. 2B). The product distribution demon-
strates that FF was almost completely transformed into FA in
performance
3 h. During this process, furfural dissopropyl acetal (FDIA) was According to previous literatures, the acidic and basic sites are
observed probably due to the acetalization of FF with 2-PrOH. crucial for the MPV reaction.27,32,48,49 To gain more insight
Notably, FDIA only existed for a short reaction time and con- into the correlation between the acid/base properties and
verted to FF with the increase in the reaction time. When the activity of Zr-tannin, we performed extensive characterizations,
reaction time was prolonged to 3 h, 2-(isopropoxymethyl)- including NH3-TPD, CO2-TPD, and pyridine-adsorbed FT-IR to
furan (IPMA) as a by-product was formed and the FA selectivity investigate the formation of strong acid–base catalytic sites in
decreased slightly. This phenomenon is consistent with the Zr-tannin. The acid/base properties of Zr-tannin and ZrO2 were
previously reported product distribution in the MPV reduction first compared by NH3-TPD and CO2-TPD methods (Fig. 3A
of FF.28,47
and B). No NH3/CO2 adsorption was observed for ZrO2, while a
As for the durability tests, Zr-tannin exhibited good recycl- large amount of NH3/CO2 desorption and a longer desorption
ability for the reduction of FF in a five-run test, only a slight time suggested that Zr-tannin possessed high contents of both
decrease in conversion was observed in the first two cycles acidic sites and basic sites. This could be ascribed to the chela-
(Fig. 2C). The recovered Zr-tannin illustrated a similar FT-IR tion between –Ar–OH groups and Zr4+ causing the formation
spectrum to that of the fresh one (Fig. S5†). Moreover, the con- of –Ar–O2–Zr–O2–Ar– frameworks that bare both acidic (Zr4+)
centration of Zr was lower than 2 ppm in the reaction solution and basic (–Ar–O2–) sites.22,28,50 Based on the quantitative ana-
as detected by ICP-AES, suggesting the negligible leaching of lysis of the peak area, the amount of total acidic sites was cal-
active sites. The results of the thermal filtration experiment culated to be 0.114 mmol g−1, and the amount of basic sites
demonstrate that the reaction was completely stopped after the was calculated to be 0.322 mmol g−1
removal of the catalyst from the reaction mixture at 60 min
Pyridine-adsorbed FT-IR spectra were further obtained at
reaction time (Fig. S6†), further confirming the heterogeneous two desorption temperatures of 150 °C and 250 °C to have a
nature and high durability of Zr-tannin for MPV reduction.
deep insight into the Lewis and Brønsted acidic sites of Zr-
.
We compared Zr-tannin catalyst for the MPV reduction of tannin (Fig. 3C). A series of bands occurred for Zr-tannin at
FF with other previously reported catalysts in literatures both 150 °C and 250 °C detecting temperatures. These bands
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Table 1 Results of the Zr-tannin-catalyzed MPV reduction of various carbonyl compounds to alcohols
Entry
1
Substrates
Products
Time (h)
3
T (°C)
Con. (%)
96
Sel. (%)
95
80
2
5
100
95
94
3
4
4
2
80
80
95
96
97
98
5
6
7
5
3
4
100
100
90
94
87
99
86
97
99
8
5
120
98
93
9
1.5
14
80
98
93
98
96
10
150
11
8
150
98
95
Reaction conditions: 1 mmol substrate in 10 mL 2-PrOH with 100 mg catalyst Zr-tannin.
suggested to arise from the rest of the Ar–OH groups that
don’t have coordination with Zr in tannin. Acid sites are well
known active sites for enhancing the adsorption and activation
of substrates in MPV reduction.28,51 Thus, the moderate acidity
in Zr-tannin should make the MPV reduction more favourable.
In the Zr 3d XPS spectra of Zr-tannin and ZrO2 (Fig. 4A),
ZrO2 showed binding energies at 182.1 eV for Zr 3d5/2 and
184.4 eV for Zr 3d3/2. For Zr-tannin, these peaks shifted slightly
to a higher level, the intensity of which decreased significantly
in comparison with that of ZrO2. This observation can be
attributed to a higher positive charge on Zr in Zr-tannin, mani-
festing a stronger Lewis acidity of Zr-tannin.25–29 Meanwhile,
the higher O 1s binding energy of Zr-tannin as compared with
that of ZrO2 assigned to a more negative charge on the oxygen
atoms in Zr-tannin manifested a stronger basic strength of
Zr-tannin (Fig. 4B).
Fig. 3 (A) NH3-TPD and (B) CO2-TPD spectra for ZrO2 and Zr-tannin;
(C) pyridine-adsorbed FT-IR spectra of Zr-tannin; (D) the concentration
of Brønsted and Lewis acid sites.
can be assigned to the pyridine interacting with the Lewis acid
sites (LA) (1450 and 1610 cm−1), Brønsted acid sites (BA)
(1540 and 1640 cm−1), or both of these two acid sites
(1490 cm−1).25,26 Based on the equations in Experimental
section, the Brønsted/Lewis acid ratio was calculated to be 0.42
and 1.13 at 150 °C and 250 °C, respectively (Fig. 3D). The LA
Fig. 4 (A) Zr 3d XPS spectra; (B) O 1s XPS spectra of ZrO2 and Zr-
sites are suggested to arise from Zr4+, and the BA sites are tannin.
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utilization of tannins as building blocks for both fabricating
biomacromolecule catalytic materials and producing valuable
platform chemicals presents a sustainable chemical conver-
sion process.
Conflicts of interest
Scheme 2 Possible mechanism for the Zr-tannin-catalyzed MPV
reduction of carbonyl compounds with 2-PrOH.
The authors declare no competing financial interest.
Acknowledgements
As discussed above, using tannins as the building block to
chelate with Zr4+ can help form robust Ar–O2–Zr–O2–Ar frame-
works with abundant acidic and basic sites, which seem to be
key factors for the MPV reduction of carbonyl compounds to
alcohols. Based on the experimental results in this work, and
according to previous reports,25,26,30,31 we proposed a possible
mechanism for the Zr-tannin-catalyzed MPV reaction
(Scheme 2). 2-PrOH was first dissociated into alkoxide and
hydrogen on the acidic–basic coupled sites (–Ar–O2–Zr–);
meanwhile, the carbonyl group in the substrate was activated
by electron-withdrawing Brønsted acid sites (–Ar–OH), forming
the six-membered ring transition state. Next, the direct
hydride transfer between carbonyl groups and 2-PrOH resulted
in the generation of the corresponding alcohol and acetone.
The Zr-tannin possessed a high specific surface area of
162 m2 g−1. Moreover, it showed good wettability for substrates
as demonstrated by contact angle tests (Fig. S7†). We thus pro-
posed that apart from the acid–base synergistic active sites, the
porous structure and surface wettability of Zr-tannin may also
contribute to its high catalytic activity. In order to confirm
this, we used gallic acid (the homologue of tannin) as the
building block to prepare another control catalyst Zr-GA,
which is a solid but non-porous material with a similar compo-
sition to that of Zr-tannin. However, Zr-GA displayed a much
lower activity than that of Zr-tannin in the reduction of FF to
FA, giving only 11.3% conversion and 17.1% selectivity
(Fig. 2A). Therefore, the rich porosity and good hydrophilicity
of Zr-tannin may greatly accelerate the mass transfer of sub-
strates, which allows a fast reaction between substrates and
the acid–base active sites.
The authors thank the National Natural Science Foundation of
China (no. 21978115), MOE & SAFEA for the 111 Project (No.
B13025), and the Open Fund of Jiangsu Key Laboratory for
Biomass Energy and Material (No: JSBEM201906). The authors
were also supported by the Central Laboratory of School of
Chemical and Material Engineering.
Notes and references
1 D. A. Evans, S. G. Nelson, M. R. Gagne and A. R. Muci,
J. Am. Chem. Soc., 1993, 115, 9800–9801.
2 T. Ooi, T. Miura and K. Maruoka, Angew. Chem., Int. Ed.,
1998, 37, 2347–2349.
3 K. Nishide, Y. Shigeta, K. Obata and M. Node, J. Am. Chem.
Soc., 1996, 118, 13103–13104.
4 H. Y. Liu, Q. Q. Mei, S. P. Li, Y. D. Yang, Y. Y. Wang,
H. Z. Liu, L. R. Zheng, P. F. An, J. Zhang and B. X. Han,
Chem. Commun., 2018, 54, 908–911.
5 C. M. Piquerasa, V. Pucciaa, D. A. Vegab and M. A. Volpe,
Appl. Catal., B, 2016, 185, 265–271.
6 F. Gonell, M. Boronat and A. Corma, Catal. Sci. Technol.,
2017, 7, 2865–2873.
7 R. López-Asensioa, J. A. Ceciliaa, C. P. Jiménez-Gómeza,
C. García-Sanchob, R. Moreno-Tosta and P. Maireles-
Torres, Appl. Catal., A, 2018, 556, 1–9.
8 J. N. Wei, X. J. Cao, T. Wang, H. Liu, X. Tang, X. H. Zheng,
Y. Sun, T. Z. Lei, S. J. Liu and L. Lin, Catal. Sci. Technol.,
2018, 8, 4474–4484.
9 A. H. Valkar, K. H. Cho, S. K. Chitale, D. Y. Hong,
G. Y. Cha, U. H. Lee, D. W. Hwang, C. Serre, J. S. Chang
and Y. K. Hwang, Green Chem., 2016, 18, 4542–4552.
10 S. Rojas-Buzo, P. Garcia-Garcia and A. Corma,
ChemSusChem, 2018, 11, 432–438.
Conclusions
In summary, we have demonstrated the successful application
of the natural resource tannin as the building block for immo- 11 M. Koehle and R. F. Lobo, Catal. Sci. Technol., 2016, 33,
bilizing Zr4+ catalyst via a facile one-step assembly method.
3018–3026.
The obtained Zr-tannin hybrid was found to be a highly 12 W. C. Yun, M. T. Yang and K. Y. Lin, J. Colloid Interface Sci.,
efficient catalyst for MPV reductions using 2-PrOH as the 2019, 543, 52–63.
hydrogen source under mild reaction conditions. Furthermore, 13 V. L. Sushkevich, I. I. Ivanova, S. Tolborg and E. Taarning,
Zr-tannin possessed stable recyclability and good universality J. Catal., 2014, 316, 121–129.
for various substrates. The remarkable catalytic performance 14 S. Song, L. Di, G. Wu, L. J. Guan and L. D. Li, Appl. Catal.,
of Zr-tannin can be attributed to the acidic (originating from B, 2017, 205, 393–403.
Zr4+) and basic (originating from –Ar–O2–) cooperative active 15 H. P. Winoto, Z. A. Fikri, J. M. Ha, Y. K. Park, H. Lee,
sites, porous structure, and good wettability for reactants. The
D. J. Suh and J. Jae, Appl. Catal., B, 2019, 241, 588–597.
This journal is © The Royal Society of Chemistry 2020
Green Chem., 2020, 22, 180–186 | 185

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Paper
Green Chemistry
16 F. Li, L. J. France, Z. Cai, Y. W. Li, S. J. Liu, H. M. Liu, 35 A. M. Bacelo, S. C. R. Santos and C. M. S. Botelho, Chem.
J. X. Long and X. H. LI, Appl. Catal., B, 2017, 214, 67–77. Eng. J., 2016, 303, 575–587.
17 G. Z. Xu, C. Liu, A. Y. Hu, Y. M. Xia, H. J. Wang and X. Liu, 36 Q. Dai, Q. Yu, Y. Tian, X. L. Xie, A. X. Song, F. Caruso,
Mol. Catal., 2019, 475, 110384.
18 A. K. Mohanty, S. Vivekanandhan, J. M. Pin and M. Misra,
Science, 2018, 362, 536–542.
19 X. Zhang, M. Jiang, N. Niu, Z. Chen, S. Li, S. Liu and J. Li,
ChemSusChem, 2018, 11, 11–24.
20 T. P. J. Knowles and R. Mezzenga, Adv. Mater., 2016, 28,
6546–6561.
21 M. A. Rahim, S. L. Kristufek, S. Pan, J. J. Richardson and
F. Caruso, Angew. Chem., Int. Ed., 2019, 58, 1904–1927.
22 S. Zhou, F. Dai, Y. Chen, C. Dang and H. Qi, Green Chem.,
2019, 21, 1421–1431.
J. C. Hao and J. W. Cui, ACS Appl. Mater. Interfaces, 2019,
11, 29305–29311.
37 P. Chowdhury, P. K. B. Nagesh, E. Hatami, S. Wagh,
N. Dan, M. K. Tripathi, S. Khan, B. B. Meibohm,
S. C. Chauhan, M. Jaggi and M. M. Yallapu, J. Colloid
Interface Sci., 2019, 535, 133–148.
38 B. J. Kim, S. Han, K. B. Lee and I. S. Choi, Adv. Mater.,
2017, 29, 1700784.
39 J. Wei, Y. Liang, Y. X. Hu, B. Kong, J. Zhang, Q. F. Gu,
Y. P. Tong, X. B. Wang, S. P. Jiang and H. T. Wang, Angew.
Chem., Int. Ed., 2016, 55, 12470–12474.
23 H. Li, X. F. Liu, T. T. Yang, W. F. Zhao, S. Saravanamurugan 40 T. Zeng, X. L. Zhang, Y. Y. Guo, H. Y. Niu and Y. Q. Cai,
and S. Yang, ChemSusChem, 2017, 10, 1761–1770. J. Mater. Chem. A, 2014, 2, 14807–14811.
24 X. Wang, W. Y. Gao, Z. Niu, L. Wojtas, J. A. Perman, 41 L. Z. Zhou, P. H. Shao, K. Zhang, L. M. Yang, D. You,
Y. S. Chen, B. Aguila and S. Q. Ma, Chem. Commun., 2018,
54, 1170–1173.
H. Shi, S. G. Pavlostathis, W. Q. Lai, D. L. Liang and
X. B. Luo, Chem. Eng. J., 2019, 364, 160–166.
25 J. Song, B. Zhou, H. Zhou, L. Wu, Q. Meng, Z. Liu and 42 N. A. S. Ramli and N. A. S. Amin, Appl. Catal., B, 2015, 5,
B. Han, Angew. Chem., Int. Ed., 2015, 54, 9399–9403.
26 H. Li, T. Yang and Z. Fang, Appl. Catal., B, 2018, 227, 79–89.
27 H. Li, J. He, A. Riisager, S. Saravanamurugan, B. Song and
S. Yang, ACS Catal., 2016, 6, 7722–7727.
28 S. Zhou, F. Dai, Z. Xiang, T. Song, D. Liu, F. Lu and H. Qi,
Appl. Catal., B, 2019, 248, 31–43.
487–498.
43 B. B. Li, Z. F. Ju, M. Zhou and D. Q. Yuan, Angew. Chem.,
Int. Ed., 2019, 58, 7687–7691.
44 J. Y. Lee, O. K. Farha, J. Roberts, K. A. Scheidt,
S. B. T. Nguyen and J. T. Hupp, Chem. Soc. Rev., 2009, 38,
1450–1459.
29 Y. F. Sha, Z. H. Xiao, H. C. Zhou, K. L. Yang, Y. M. Song, 45 M. Yoon, R. Srirambalaji and K. Kim, Chem. Rev., 2011,
N. LI, R. X. He, K. D. Zhi and Q. S. Liu, Green Chem., 2017,
19, 4829–4837.
30 L. Hu, T. Li, J. X. Xu, A. Y. He, X. Tang, X. Z. Chu and
J. M. Xu, Chem. Eng. J., 2018, 352, 110–119.
112, 1196–1231.
46 M. Kim, J. F. Cahill, Y. X. Su, K. A. Prather and
S. M. Cohen, Chem. Sci., 2012, 3, 126–130.
47 H. Li, Y. Li, Z. Fang and R. L. Smith, Jr., Catal. Today, 2019,
319, 84–92.
31 C. Xie, J. L. Song, B. W. Zhou, J. Y. Hu, Z. R. Zhang,
P. Zhang, Z. W. Jiang and B. X. Han, ACS Sustainable Chem. 48 T. Komanoya, K. Nakajima, M. Kitano and M. Hara, J. Phys.
Eng. J., 2016, 4, 6231–6236. Chem. C, 2015, 119, 26540–26546.
32 H. Li, Z. Fang, J. He and S. Yang, ChemSusChem, 2017, 10, 49 Y. Román-Leshkov and M. E. Davis, ACS Catal., 2011, 1,
681–686. 1566–1580.
33 J. L. Hao, L. M. Han, Y. F. Sha, X. X. Yu, H. Y. Liu, X. Y. Ma, 50 J. L. Song, L. Q. Wu, B. W. Zhou, H. C. Zhou, H. L. Fan,
Y. Z. Yang, H. C. Zhou and Q. S. Liu, Fuel, 2019, 239, 1304–
1314.
Y. Y. Yang, Q. L. Mei and B. X. Han, Green Chem., 2015, 17,
1626–1632.
34 A. Soto-Vaca, A. Gutierrez, J. N. Losso, Z. M. Xu and 51 H. Y. Luo, D. F. Consoli, W. R. Gunther and Y. Román-
J. W. Finley, J. Agric. Food Chem., 2012, 60, 6658–6677. Leshkov, J. Catal., 2014, 320, 198–207.
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