Simple basic zirconium carbonate: Low temperature catalysis for hydrogen transfer of biomass-derived carboxides

Article abstract of DOI:10.1039/c9gc03033f

A simple basic zirconium carbonate (BZC), which can be produced on a large scale in industry, was studied for hydrogen transfer of biomass-derived carboxides and exhibited excellent catalytic properties at low temperatures, especially for the conversion of furfural (FUR) to furfuryl alcohol (FFA). With the catalyst, the reduction reaction of FUR was efficiently performed at low temperatures (below 100 °C) and an FFA yield of 98.66% was obtained even at room temperature. When the temperature reached 180 °C, the yield of FFA quickly reached 90.29% within 15 minutes. During the reaction, the changes of the functional groups of the reactants and products were monitored by in situ ATR-IR spectroscopy in real time, which provided a basis for the proposed reaction mechanism. Further, the ATR-IR spectroscopy and XPS results of the different catalysts showed that BZC has the strongest acidity among all the comparative catalysts, which is consistent with its best catalytic performance. In addition, reaction kinetics were also studied.

Full text of DOI:10.1039/c9gc03033f

Green Chemistry
View Article Online
View Journal | View Issue
PAPER
Simple basic zirconium carbonate: low
temperature catalysis for hydrogen transfer
of biomass-derived carboxides†
Cite this: Green Chem., 2019, 21,
5969
Mingwei Ma,a Pan Hou,a Jingjie Cao,a Hui Liu,a Xinyu Yan,a Xingliang Xu,b
Huijuan Yue, a Ge Tian *a and Shouhua Fenga
A simple basic zirconium carbonate (BZC), which can be produced on a large scale in industry, was
studied for hydrogen transfer of biomass-derived carboxides and exhibited excellent catalytic properties
at low temperatures, especially for the conversion of furfural (FUR) to furfuryl alcohol (FFA). With the cata-
lyst, the reduction reaction of FUR was efficiently performed at low temperatures (below 100 °C) and an
FFA yield of 98.66% was obtained even at room temperature. When the temperature reached 180 °C, the
yield of FFA quickly reached 90.29% within 15 minutes. During the reaction, the changes of the functional
groups of the reactants and products were monitored by in situ ATR-IR spectroscopy in real time, which
provided a basis for the proposed reaction mechanism. Further, the ATR-IR spectroscopy and XPS results
of the different catalysts showed that BZC has the strongest acidity among all the comparative catalysts,
which is consistent with its best catalytic performance. In addition, reaction kinetics were also studied.
Received 28th August 2019,
Accepted 1st October 2019
DOI: 10.1039/c9gc03033f
rsc.li/greenchem
Different approaches and catalysts are used in the hydro-
genation of biomass-derived carboxides to achieve their con-
Introduction
As we all know, the survival and development of mankind version to valuable chemicals.28–31 An efficient strategy for the
cannot be separated from energy. With the rapid growth of the hydrogenation of the carboxides has been developed using
world’s energy demand, conventional energy such as coal, oil molecular hydrogen (H2) as a hydrogen source in the presence
and natural gas will eventually be exhausted. Therefore, the of zero-valent precious or nonprecious metal-based catalysts
search for renewable resources to provide fuels and chemicals (such as: Pd,32,33 Ru,34,35 Rh,36 Pt,37,38 Re,39 Ni,40,41 Co,42,43
has received widespread attention.1,2 Among many renewable Cu44,45 and so on). However, the safety of storage and transpor-
resources, only biomass can provide a steady stream of fuels tation of H2, the hardness of the reaction conditions (high
and chemicals.3,4 As a result, much effort has been devoted to temperature and pressure), encourage us to explore alternative
the development of suitable catalytic processes to produce a synthetic methods. The Meerwein–Ponndorf–Verley (MPV)
variety of platforms and valuable chemicals from sugars or reaction, one of the catalytic transfer hydrogenations (CTH)
directly from lignocellulose.5–10 Among the chemicals derived reactions, is an efficient synthetic route for the selective
from biomass, carboxides (furfural (FUR),11,12 5-hydroxy- reduction of carboxides using secondary alcohols instead
methylfurfural (5-HMF),13–16 levulinic acid (LA) or its of hydrogen as a source of hydrogen,46–48 and different
esters,17,18 ketone compounds,19 etc.) are an important class of types of catalysts are used in the reaction, including
chemicals with broad applications, because they can be metal alkoxides,49–51 metal oxides or hydroxides,52,53 metal
further converted into more valuable chemicals such as fur- complexes,4,54 various zeolites,55,56 etc. Among these catalysts,
furyl alcohol (FFA),20,21 γ-valerolactone (γ-GVL),22–24 2,5-bia zirconium-based catalysts are widely applied due to their acid–
(hydroxymethyl)fural (BHMF)25–27 and so on.
base characteristics (Zr4+ and O2−, respectively) which play a
key role in the MPV reduction,57 such as ZrO2, Zr(OH)4, zirco-
nium complexes, Zr-containing zeolites, etc.4,52,53,55,58 And an
overview on the hydrogen transfer of biomass-derived carbox-
ides using various catalysts in recent years is provided in
Table S1.† Zhang et al., Yang et al., etc. found that above
150 °C, metal oxides, metal hydroxides and metals, etc. (ZrO2,
Zr(OH)4, Al–Zr oxides, Al2O3, Ru/C, γ-Fe2O3@HAP, etc.) have
high activity for the hydrogen transfer of biomass-derived
aState Key Laboratory of Inorganic Synthesis and Preparative Chemistry,
College of Chemistry, Jilin University, Changchun 130012, P. R. China.
E-mail: tiange@jlu.edu.cn
bCollege of Chemistry and Material Science, Shandong Agricultural University,
Taian 271018, P. R. China
†Electronic supplementary information (ESI) available. See DOI: 10.1039/
c9gc03033f
This journal is © The Royal Society of Chemistry 2019
Green Chem., 2019, 21, 5969–5979 | 5969

View Article Online
Paper
Green Chemistry
carboxides (FUR, HMF, LA or it esters).48,59–63 Han et al., Yang
et al., etc. explored the catalytic performance of zirconium
complexes (Zr-PhyA, ZrPN, etc.) for the reaction at a lower reac-
tion temperature (Yang et al.: 90% yield of FFA, 100 °C, 12 h.)
or a shorter reaction time (Han et al.: 93.3% yield of FFA,
100 °C, 2 h.).64–66 Liu et al. researched that Zr-HAs has a high
catalytic activity for the hydrogen transfer of FUR to FFA at
50–70 °C (96.9% yield of FFA), which is the lowest temperature
for reducing FUR.67
A simple basic zirconium carbonate (BZC) catalyst conform-
ing to the concept of green sustainable development is pre-
pared in aqueous solution by adjustment of pH and room
temperature agitation without energy input (Scheme S1†). As a
vital commercial solid base, it is used in the preparation of zir-
conia and zirconium-based catalyst carrier,68,69 and is also
widely applied in textile, paint, paper and other industries.
Here, the commercialized BZC was applied to the hydrogen
transfer of biomass-derived carboxides at low temperatures,
which has better catalytic performance than catalysts such as
ZrO2 and Zr(OH)4, etc., even is superior to most zirconium
complexes. With the catalyst, the reduction reaction of FUR
was efficiently performed at very low temperatures (below
100 °C). When the temperature is 180° C, FUR is quickly and
almost completely converted to FFA in a very short time
(15 min). Further, with in situ ATR-IR and ATR-IR tests, more
information about the reaction process was acquired by moni-
toring changes in functional groups in the reaction and
surface chemistry of the catalyst. In addition, reaction kinetics
and a possible mechanism were also studied.
Fig. 1 Schematic diagram of an autoclave with in situ ATR-IR
monitoring.
for an intended reaction time. After the reaction, the autoclave
was taken out and cooled to ambient temperature. The hydro-
gen transfer reactions of xylose-derived FUR and other carbox-
ides were also carried out under the same conditions. Besides,
a scaled-up hydrogen transfer experiment of FUR was per-
formed in 300 ml stainless steel autoclave (JULABO) with
heating jacket (Fig. 1). Typically, FUR (15 mL), 2-PrOH
(135 mL), and catalyst (1 g) were charged into the autoclave,
then sealed and heated to 120 °C for an intended reaction
time.
Identification of liquid products in the reaction mixture
was achieved by the TRACE ISQ GC-MS (Thermo Scientific Co,
TR-WAX-MS column 30.0 m × 320 μm × 0.25 μm). The tempera-
ture program started at 60 °C for 1 min, then increased from
60 °C to 230 °C at a rate of 15 °C min−1 and held for 2 min.
Experimental section
Materials
Furfural (FUR), furfuryl alcohol (FFA), levulinate esters,
γ-valerolactone, 5-hydroxymethylfurfural (5-HMF), 2,5-bis
(hydroxymethyl)furan, cyclohexanone, cyclohexanol, citral,
citrate, cinnamaldehyde and cinnamyl alcohol were purchased
from TCI Chemical Reagent Company (Shanghai, China).
Basic zirconium carbonate, basic nickel carbonate and
D-(+)-xylose were purchased from Aladdin Industrial
Corporation. Zr(OH)4, ZrO2, basic copper carbonate,
Mg(NO3)2·6H2O, Zn(NO3)2·6H2O, Na2CO3, benzoic acid, pyridine,
isopropanol, NaCl, tetrahydrofuran (THF), and AlCl3·6H2O
were purchased from Sinopharm Chemical Reagent Company
(Shanghai, China). All chemicals were used without further
purification.
Catalyst characterization
X-ray diffraction (XRD) was carried out via a Rigaku D/max-
2550 diffractometer using Cu-Kα radiation. The wavelength of
X-ray source was set at 0.154 nm, and the step width was 0.02°
with a scanning speed of 6° per minute between two thetas of
10° and 80°. Fourier transform infrared (FT-IR) spectra were
recorded between 400 to 4000 cm−1 by using Bruker VERTEXV
80 V spectrometer. The NH3-IR and HCOOH-IR spectra were
recorded on a Bruker 80 v with a range of 600–4000 cm−1 for
the MCT detector (detailed information on ESI†). The thermo-
gravimetric (TG) analysis was performed using a thermo-
gravimetric analysis system (TG: PerkinElmer Instruments)
under air atmosphere at a heating rate of 10 °C min−1
Brunauer–Emmett–Teller (BET) surface area was measured on
.
Hydrogen transfer reaction of biomass-derived carboxides and
sample analysis
an Asap 2420 surface adsorption apparatus. The elemental
Hydrogen transfer reaction of biomass-derived carboxides was compositions of catalysts were determined by inductively
carried out in a stainless-steel autoclave (40 mL) with a mag- coupled plasma (ICP) on an Optima 3300 DV (PerkinElmer
netic stirrer which was heated in a temperature-controlled oil Instruments). X-ray photoelectron spectroscopy (XPS) measure-
bath. Typically, FUR (0.67 mmol), isopropanol (2-PrOH) ments were performed using ESCALAB250 photoelectron
(20 mL), and catalyst (0.1 g) were charged into the reactor spectrometer equipped with a charge neutralizer and an Mg
which was then sealed and heated to a designed temperature Kα X-ray source. The morphology of the samples was investi-
5970 | Green Chem., 2019, 21, 5969–5979
This journal is © The Royal Society of Chemistry 2019

View Article Online
Green Chemistry
Paper
gated by transmission electron microscopy (TEM; Tecnai F20)
and scanning electron microscopy (SEM; Jeol JSM-6700F).
In situ ATR-IR measurements and ATR-IR measurements
The in situ ATR-IR measurements were carried out on a
VERTEXV 80 V FT-IR spectrometer (Bruker) equipped with a
liquid nitrogen-cooled MCT detector. The equipment is an
in situ mid-infrared based system that monitors the reactions
in real time for further reaction information. And it is con-
nected to a 300 ml stainless steel autoclave (JULABO) for cata-
lytic reaction through an optical fiber with a high temperature
diamond ATR probe (Bruker). From the Fig. 1, the fiber optic
probe is placed near the magnet at the bottom of the autoclave
for better monitoring of the reaction.
Since the concentration of FUR in the solution was too low,
its infrared peak was masked by the peak of 2-PrOH. Typically,
FUR (60 mmol), 2-PrOH (150 mL), and catalyst (1 g) were
charged into the autoclave and then stirred with 500 rpm at
120 °C. During the reaction, ATR-IR spectra were recorded
every 1 min for 2 h with averaging 32 scans at the resolution of
2 cm−1 in the 3500–600 cm−1. And air was used as the back-
ground for the test.
Fig. 2 The characterization of different Zr-based catalysts. XRD pat-
terns (a). FT-IR spectra (b). N2 adsorption–desorption isotherm and pore
size distribution of the BZC catalyst (c). XPS spectra of Zr 3d (d).
The surface chemistry of zirconium-based catalyst was also
studied with ATR-IR spectroscopy on the VERTEXV 80 V FT-IR
spectrometer (Bruker) equipped with a Platinum-ATR A225/Q
accessory (Bruker).
Typically, 6 mol FUR and 0.1 g BZC catalyst were mixed for
10 min in ultrasound and then placed in a 60 °C water bath
for 30 min. One or two drops of the suspension were taken out
and placed on the diamond of the accessory for testing.
During the measurements, ATR-IR spectra were collected by
averaging 64 scans at the resolution of 2 cm−1 in the
4000–390 cm−1. And air was also used as the background for
the test.
can be perceived, respectively. For ZrO2, the bands at 664 and
473 cm−1 belong to the stretching vibration of Zr–O.
The N2 adsorption–desorption isotherm and pore size dis-
tribution reveal that the commercialized BZC is micro meso-
pores, and the surface area and average pore diameter are
202.4 m2 g−1 and 2.1 nm, respectively (Fig. 2c and Table 1).
The surface area and pore volume for the BZC (202.4 m2 g−1
,
0.11 cm3 g−1) and Zr(OH)4 (260.9 m2 g−1, 0.19 cm3 g−1) are sig-
nificantly higher than ZrO2 (39.2 m2 g−1, 0.10 cm3 g−1), but the
pore size is smaller than it. From the TG analysis (Fig. S2†),
due to the desorption of water, the catalyst has a lower weight
loss of about 15% before 170 °C, which manifests an excellent
stability on the reaction temperatures (below 140 °C).67 And
the weight loss of the catalyst from 200 °C to 500 °C is attribu-
ted to the decomposition of BZC. Therefore, the CO2-TPD and
NH3-TPD tests could not be carried out to achieve the analysis
Results and discussion
Characterization of catalysts
XRD patterns of BZC, Zr(OH)4 and ZrO2 are given in Fig. 2a. It of acid/base strength and amount of the catalysts. However,
can be seen that both BZC and Zr(OH)4 are amorphous. For some information about the Lewis acidity can be obtained by
ZrO2, the XRD pattern shows the characteristic peaks of ZrO2 XPS analysis (Fig. 2d). The result shows that the binding
(2θ = 30.2°, 34.8°, 35.2°, 50.3°, 59.6°, 60.2°, 62.9° and 74.5°. energy values of Zr 3d in BZC are higher than that of Zr(OH)4
PDF, 50-1089). In addition, FT-IR is used to analyse the charac- and ZrO2, implying that the highest positive charge exists on
teristic absorption peaks of these samples. From the Fig. 2b, the Zr atoms in BZC, which results in the strongest Lewis
for the BZC, the typical band at 3252 cm−1 is ascribed to acidity of BZC, in good accordance with the best catalytic
stretching modes of O–H with wide absorbance. The peaks at activity of the BZC catalyst observation. In addition, three
1538 and 1385 cm−1 are assigned the asymmetric stretching samples are further investigated for acid–base sites by the tests
vibration of CO32−. The peaks at 1066 and 847 cm−1 can be of the NH3-IR and HCOOH-IR spectroscopy (Fig. 3). For the
attributed to the symmetric stretching and out of plane NH3-IR spectrum (Fig. 3a and b), the peaks at 1620 cm−1 and
bending vibrations of CO32−, respectively. And the bands at 3332 cm−1 represent the Lewis acid sites, while the peak at
664 and 473 cm−1 are attributed to the stretching vibration of 1460 cm−1 represents the Brønsted acid sites, which is similar
Zr–O. For the Zr(OH)4, it has the same stretching modes of to that reported in the literature.70,71 Obviously, no peak at
O–H (3404 cm−1) and stretching vibration of Zr–O (664 and 1460 cm−1 testifies that no Brønsted acid sites exist in the cata-
473 cm−1) as BZC. And the peaks at 1580 cm−1 and 1330 cm−1 lysts. For the peaks of Lewis acid sites, there is a tendency that
corresponding to O–H bending vibration of water and Zr–OH the peak intensity of BZC is greater than Zr(OH)4 and ZrO2,
This journal is © The Royal Society of Chemistry 2019
Green Chem., 2019, 21, 5969–5979 | 5971

View Article Online
Paper
Green Chemistry
Table 1 Physicochemical properties of catalyst
BET surface
Pore volume
Pore size
(nm)
Zr contenta
(wt%)
Zr amount of 0.1 g
catalystb (mmol)
Entry
Catalyst
area (m2 g−1
)
(cm3 g−1
)
1
2
3
BZC
Zr(OH)4
ZrO2
202.4
260.9
39.2
0.11
0.19
0.10
2.2
2.9
11.2
32.6
38.9
72.5
0.357
0.426
0.794
a The content of Zr was determined by ICP. b It is calculated by ICP results.
Fig. 4 Elemental mapping images (a) and SEM-EDS data (b) of the BZC
catalyst.
them, the mass percentage of Zr content is approximately the
same as the result of ICP test (Table 1).
ATR-IR studies of FUR absorbed on different catalyst at 60 °C
Fig. 3 NH3-IR (a and b) and HCOOH-IR (c and d) spectra of different
Zr-based catalysts.
In order to get detailed information about the surface-bonding
state of FUR adsorbed on catalysts, ATR-IR spectroscopy was
used to investigate the interactions between FUR and the
different Zr-based catalysts (Fig. 5). Compared with the IR
spectrum of FUR (Fig. 5a), no peak position change occurs in
the different Zr-based catalysts adsorbing FUR except the peak
near 1668 cm−1. The changed peak is assigned to the stretch-
ing vibration of the CvO bond (FUR) has undergone a signifi-
cant red shift from 1668 cm−1 to 1666 cm−1 after mixed with
BZC (Fig. 5b). The result indicates a stronger interaction exists
between the BZC and the CvO band of FUR, compared with
Zr(OH)4 and ZrO2. According to the relevant literature,4,47,52
CvO is activated by the Lewis acid (Zr4+) to achieve the
purpose of hydrogen transfer reaction. Thus, the red shift of
indicating that BZC has more Lewis acid sites. From
HCOOH-IR spectrum (Fig. 3c), the peak at 1368 cm−1 is
ascribed to the symmetric stretching vibration of CO O−.
While the peak at 1562 cm−1 and its shoulders were divided
into multi-peaks displayed in Fig. 3d. Among the multi-peaks,
the peaks at 1565 cm−1 and 1653 cm−1 are attributed to the
stretching vibration and bending vibration of C–H, respect-
ively, while the peaks at 1615 cm−1 and 1716 cm−1 are respect-
ively assigned to strong basic and weak basic sites on the cata-
lyst surface,72–74 which demonstrates that the basic sites of the
BZC sample is the strongest among the three samples.
Therefore, the conclusion is drawn that the BZC catalyst has
the most acid–base sites than Zr(OH)4 and ZrO2, which makes
it have the best catalytic activity in the hydrogen transfer reac-
tions of biomass-derived carboxides.
SEM and TEM images of BZC demonstrate that the BZC is
composed of particles with no uniform shape (Fig. 4 and S3†).
Elemental mapping reveals a homogeneous distribution of Zr,
O and C elements on the surface of the BZC (Fig. 4a). EDS ana-
lysis by selecting two points from the BZC sample shows that
there are four elements of Zr, O, C and Si (caused by silica
slice for dispersing catalyst) in the catalysts, and the mass per-
centage and atomic percentage of each element at two points
are basically the same, which also demonstrates the uniformity
Fig. 5 ATR-IR spectra of FUR adsorbed on different Zr-based catalysts
of the element distribution of the catalyst (Fig. 4b). Among in the complete investigated region (a) and 1625–1705 cm−1 region (b).
5972 | Green Chem., 2019, 21, 5969–5979
This journal is © The Royal Society of Chemistry 2019

View Article Online
Green Chemistry
Paper
the CvO peak position is caused by Zr4+, and the red shift intensity is gradually increased, illustrating the formation of
induced by BZC is the largest, proving that it has the strongest CP. As a result, it is found that in the hydrogen transfer reac-
or most Lewis acidity among the three catalysts. This allows tion, the reduced reaction of FUR proceeds simultaneously
the BZC catalyst to exhibit the best catalytic performance for with the formation of CP. Further analysis of Fig. 6c, the peak
hydrogen transfer of biomass-derived carboxides and is con- at 1367 cm−1 is attributed to the C–H bending vibration of the
sistent with the results of XPS and NH3-IR. In addition, influ- aldehyde group, and its intensity gradually decreases with
enced by the electronic effect of Zr4+ on the CvO group, the time due to the reduction of the aldehyde group. Meanwhile,
vibrational peak of the C–H bond on the aldehyde group dis- since the aldehyde group is reduced, the effect of the conju-
appears, further indicating that the Zr4+ (Lewis acid) can acti- gation effect of CvO bond on the CvC bond of furan ring dis-
vate the CvO group (Fig. S4†).
appears, which causes a change in the stretching vibration
peak of the CvC bond, including a weakening of the peak
intensity at 1569 cm−1 (CvC double bond stretching vibration
In situ ATR-IR studies of the hydrogen transfer of FUR
To gain insight into the reaction mechanism, in situ ATR-IR of FUR), and an enhancement of the peak intensity at
was used to monitor the reaction progress. Under normal reac- 1505 cm−1 (CvC double bond stretching vibration of FFA).
tion conditions (5.03 mmol FUR, 150 mL 2-PrOH, 0.75 g cata- From Fig. 6d, the enhancement of the bending vibration of the
lyst), due to the excess of 2-PrOH, no significant peak position O–H (731 cm−1) and the stretching vibration of the C–O
change is observed in the IR spectrum of 600–3500 cm−1 at (hydroxyl) (1011 cm−1) belonging to the FFA is also observed.
80 °C for 5 h (Fig. S5†).
Similarly, the bending vibration of the C–H in the olefin of
The progress of the reaction is continuously monitored FUR/FFA also shifts from 758 to 742 cm−1 due to the effect of
after enlarging the amount of FUR (60 mmol FUR, 150 mL the conjugation effect. In summary, the monitoring of the
2-PrOH, 1 g catalyst) through infrared spectroscopy at 120° C above reaction process helps us understand the reaction
for 2 h. At this time, although isopropanol is in excess, mechanism.
changes in the characteristic peaks of the functional groups of
Catalytic activity of the various catalysts for hydrogen transfer
of FUR
FUR, FFA and acetone (CP) can still be observed in the range
of 600–3500 cm−1 (Fig. 6a). For the hydrogen transfer reaction
of FUR, it is most important to monitor the changes of carbo- In our research, FUR, representative of biomass-derived carb-
nyl functional groups of FUR and CP. From Fig. 6b, that the oxides, was used as a model reactant to examine catalytic
intensity of the absorption peak at 1675 cm−1 corresponding activity of various catalysts for the production of FFA through
to the stretching vibration of CvO of FUR decreases with time the hydrogen transfer reaction with 2-PrOH as a hydrogen
until it disappears, suggests that the aldehyde group of FUR is donor (Table 2). The reaction did not occur without catalyst
gradually reduced in the reaction. The two absorption peaks at (Table 2, entry 1). Among the tested catalysts, BZC showed the
1715 and 1224 cm−1 are attributed to the stretching vibration highest activity with a FFA yield of 96.67% at 80 °C with 5 h
and bending vibration of CvO of CP, respectively, and their (Table 2, entry 2). For comparison, ZrO2 only displayed a rela-
Fig. 6 In situ ATR-IR spectra during the hydrogen transfer of FUR in 2-PrOH over the BZC at 120 °C (FUR (60 mmol), 2-PrOH (150 mL) and catalyst
(1 g)). The complete investigated region (a). Partial magnification of the investigated region (b, c and d).
This journal is © The Royal Society of Chemistry 2019
Green Chem., 2019, 21, 5969–5979 | 5973

View Article Online
Paper
Green Chemistry
Table 2 Hydrogen transfer reaction of FUR to FFA with isopropanol as solvent over various catalysts
Conversion
(%)
Yield
(%)
Selectivity
(%)
Formation ratea
TOFb
Entry
Catalyst
(mmol g−1 h−1
)
(h−1
)
1c
2
3
0
BZC
ZrO2
Zr(OH)4
BZC
<1
0
0
0
0
97.69
4.15
65.04
71.99
46.97
4.94
3.35
28.40
5.45
96.67
3.36
63.65
68.65
31.25
2.14
1.12
23.08
2.24
98.95
80.96
97.86
95.36
66.53
43.31
33.53
81.26
41.10
1.29
0.04
0.85
0.92
0.42
0.03
0.02
0.3
0.366
0.007
0.204
0.270
0.176
—
—
—
—
4
5d
6e
7f
8g
9h
10i
BZC
BMC-Mg
BZC-Zn
BNC-Ni
BCC-Cu
0.03
Conditions: Catalyst (0.1 g), FUR (0.67 mmol), 2-PrOH (20 mL), 80 °C, 5 h. a The FFA formation rate is defined as mmol (formed FFA)/[g (catalyst
amount) × h (time)]. b TOF is defined as mmol (converted FUR)/[mmol (total metal is measured by ICP) × h (time)]. c Reaction without any cata-
lyst. d 5 mmol of pyridine was added additionally. e 5 mmol of benzoic acid was added additionally. f BMC-Mg is basic magnesium carbonate.
g BZC-Zn is basic zinc carbonate. h BZC-Ni is basic nickel carbonate. i BZC-Cu is basic copper carbonate.
tively poor activity with a FFA yield of 3.36% (Table 2, entry 3), ture for 7 d, no FFA product was produced here, indicating
and Zr(OH)4 also exhibited a low activity with a FFA yield of that the catalyst has good catalytic activity for the hydrogen
63.65% (Table 2, entry 4), which are consistent with the transfer of FUR at room temperature. As the reaction tempera-
ATR-IR studies, the XPS analysis, NH3-IR and HCOOH-IR of ture increased (from 40 °C, 60 °C, 80 °C up to 100 °C), the
the Zr-based catalysts (Fig. 2d, 5 and 3). In order to further time to maintain the yield of FFA more than 90% and an exclu-
confirm the effect of the acid–base sites on the reaction, pyri- sive selectivity to FFA was shortened gradually from 48 h to
dine/benzoic acid was added to the reaction system to poison 2 h. When the temperature was 180 °C, the catalyst exhibited a
the acid/base sites of the catalyst, respectively (Table 2, entries high activity with 90% yield of FFA in 15 minutes. Taking into
5 and 6). And the results demonstrated that the yield of FFA account the reaction temperature and reaction time, moderate
decreased from 96.67% to 68.65%/31.25% after addition of temperature and time (80 °C and 5 h) were chosen as the
pyridine/benzoic acid, which directly proved that the acid–base optimal reaction conditions for the series of reactions herein.
sites of the catalyst had a great influence on the catalytic
To further research the hydrogen transfer reaction of FUR
activity. Other basic carbonates (BMC-Mg, BZC-Zn, BNC-Ni through the BZC catalyst, kinetic studies were explored at
and BCC-Cu) showed a similar lower activity (2.14%, 1.12%, 40 °C, 60 °C and 80 °C. Since the amount of catalyst was fixed
23.08% and 2.24% yields, respectively) under the same reac- and there was a large excess of isopropanol, the reaction was
tion conditions (Table 2, entries 7–10). In addition, the FFA assumed to be a first-order reaction as a function of FUR con-
formation rate and TOF value of the different catalysts were centration. It is apparent that ln(Ct/C0) was linear with the
calculated. Moreover, the same reactions were carried out with reaction time t of hydrogen transfer of FUR (Fig. 8a). By calcu-
oxides and hydroxides of magnesium, nickel, copper and zinc lating the slope of the curve, the reaction rate constants (k)
as catalysts (Table S2†), and the results indicate that among were determined to be 0.0597, 0.2491 and 0.6022 h−1, corres-
the three types of compounds (oxides, hydroxides and basic ponding to temperatures of 40 °C, 60 °C and 80 °C, respect-
carbonates), the basic carbonates have the best catalytic ively. According to the Arrhenius plot (Fig. 8b), the activation
performance.
energy (Ea) of the hydrogen transfer of FUR to FFA over the
BZC catalyst in 2-PrOH was calculated to be 53.55 kJ mol−1
close to or lower than the reported Ea value for the reaction by
other catalysts.52,64,75 The low activation energy should be
related to the acid–base sites of the BZC catalyst.
,
Effect of reaction temperature and time on the performance of
BZC catalyst and reaction kinetics study
The influence of reaction temperature and time on the per-
formance of BZC catalyst was studied, and all experiments
were conducted at different temperatures from room tempera-
Effect of the catalyst dosage
ture (about 22 °C) to 180 °C within a certain period of time The effect of the catalyst dosage on the hydrogen transfer of
(Fig. 7). To our delight, the BZC catalyst exhibited superior FUR was researched in 2-PrOH at 80 °C for 5 h (Fig. 9). It can
catalytic performance at room temperature (Fig. 7a), and the be seen that the yield of FUR increases as the amount of cata-
yield was more than 90% over 5 d while maintaining a very lyst increases. When the amount of the catalyst is 0.1 g, a yield
high selectivity (close to 100%). In order to verify this result, of 90% or more is obtained. Continue to increase the amount
we carried out a reaction without any catalyst at room tempera- of catalyst to 0.2 g, the yield of FFA slowly increases to nearly
5974 | Green Chem., 2019, 21, 5969–5979
This journal is © The Royal Society of Chemistry 2019

View Article Online
Green Chemistry
Paper
Fig. 7 Effect of different reaction temperatures on the performance of BZC catalyst. Room temperature (a), 40 °C (b), 60 °C (c), 80 °C (d), 100 °C (e)
and 180 °C (f). Reaction condition: Catalyst (0.1 g), FUR (0.67 mmol), 2-PrOH (20 ml).
Fig. 8 First-order kinetic fit (a) for the hydrogen transfer of FUR to FFA
at different temperatures and the corresponding Arrhenius plots (b) for
the BZC catalyst. Reaction condition: Catalyst (0.1 g), FUR (0.67 mmol),
2-PrOH (20 ml).
100%. And throughout the range from 0.01 g to 2 g, the cata-
lyst exhibits extremely high selectivity to FFA. Therefore, 0.1 g
of catalyst is selected as the most appropriate amount.
Fig. 9 Effect of different amount of BZC on the hydrogen transfer of
FUR (F). Reaction condition: FUR (0.67 mmol), 2-PrOH (20 mL), 80 °C,
5 h.
Reusability and heterogeneity of the catalyst
The reusability and heterogeneity of the BZC catalyst were also
investigated. Upon completion of each cycle, the catalyst was after removal of the catalyst. After 4 hours, the BZC catalyst
separated from the liquid by filtration, washed twice with each was re-added to the reaction system, and the yield of FFA con-
5 ml of fresh acetone and 2-PrOH, and then involved in the tinued to increase to over 90%, demonstrating the heterogen-
next cycle. The conversion of FUR and the yield of FFA and eity and stability of the catalyst. Meanwhile, trace of zirconium
selectivity to FFA for seven cycles are shown in Fig. 10a. There ions (0.09 ppm) in the solution after the reaction also proved
is no considerable decrease in the conversion, yield and that the catalyst is heterogeneous and stable.
selectivity after seven cycles, proving that the catalyst is very
The stability of the catalyst was further analyzed by XRD,
stable. Leaching test of the catalyst was also explored FT-IR and SEM-EDS. The XRD pattern of the fresh catalyst is
(Fig. 10b). The reaction was stopped after 1.5 h, the catalyst similar to that of the spent catalyst with two broad and weak
was filtered out and the solution continued to react under peaks, suggesting no new phase formation after seven cycles
same conditions. The yield of FFA did not further increase (Fig. 11a). From the FT-IR spectra (Fig. 11b), compared with the
This journal is © The Royal Society of Chemistry 2019
Green Chem., 2019, 21, 5969–5979 | 5975

View Article Online
Paper
Green Chemistry
versions of other carboxides were subject to the similar con-
ditions and the results are shown in Table 3. The BZC catalyst
has remarkable catalytic performance for hydrogen transfer of
different carboxides. It is noteworthy that ketones or aldehydes
with long chains or complex structures need a longer reaction
time or harsh conditions to achieve good conversions and
yield as compared to simple aldehydes, caused by steric hin-
drance and electron-donating nature of the alkyl groups in
these molecules.
In order to make the catalytic performance of the BZC cata-
lyst more complete for biomass conversion, xylose-derived FUR
(a true biomass-derived carboxide) is researched as a represen-
tative. The related research on the catalytic conversion from
xylose to FUR has been widely studied and even
industrialized.76,77 Here, a two-phase reaction system was
established to synthesize FUR from xylose (Scheme S2†). After
the reaction, the organic phase was fractionated to get FUR
with a purity of 85.14% (containing a small amount of water,
THF, by-products, etc.) (Fig. S6 and S7†). The impure xylose-
derived FUR was used as a model carboxide to verify the true
catalytic performance of the BZC catalyst. From the results
(Fig. 12a), the yield of FFA reached 94.81% at 80 °C for 5 h,
indicating that high conversion and high yield are also
received with the biomass-derived FUR as feedstock. For re-
usability test of the catalyst (Fig. 12b), the activity of the cata-
lyst decreased a little bit, but the selectivity of the product
remained constant after five cycles. Compared with the hydro-
gen transfer of pure FUR, the catalytic activity and reusability
of the catalyst using the xylose-derived FUR as feedstock are
slightly decreased due to more carbon accumulation (Fig. S8†).
Fig. 10 Reusability (a) and leaching test (b) of the catalyst for the
hydrogen transfer of FUR. Reaction condition: Catalyst (0.31 g), FUR
(0.67 mmol), 2-PrOH (20 mL), 80 °C, 5 h.
A scaled-up hydrogen transfer experiment of FUR
In order to estimate the industrial application potential of BZC
catalyst for hydrogen transfer of FUR to FFA, a scaled-up
experiment of FUR was examined in 135 mL of 2-PrOH at
120 °C for 4 h using 15 mL of FUR with 1 g of BZC as catalyst.
The results display that a FUR yield of 88.72% is obtained,
revealing an industrial prospect for the BZC catalyst.
Fig. 11 The characterization of the BZC catalyst after 7 cycles. XRD pat-
terns (a), FT-IR spectra (b), elemental mapping images (c) and SEM-EDS
data (d).
fresh catalyst, the new absorption peaks at about 1480, 1370
and 1200 cm−1 appears in the infrared spectrum of the spent
catalyst, from which it can be inferred that some nonvolatile
organic compounds are present on the surface of the spent cata-
lyst. The compounds are responsible for the slight decrease in
catalytic activity after the first run, and the new peaks at 1480
and 1370 cm−1 are attributed to bending vibration of C–H. In
addition, from elemental mapping and SEM-EDS (Fig. 11c and
d), on the surface of the catalyst, the elemental content of the
spent catalyst is not much different from that of the fresh cata-
lyst (Fig. 4a and b), and Zr, O and C elements are uniformly dis-
persed on the surface of the spent catalyst. In summary, the
catalyst is quite stable after seven cycles.
Mechanism analysis
According to previous reports,61,78,79 the amphoteric nature of
the catalysts is the major reason for catalyzing the hydrogen
transfer of carboxides. For Zr-containing catalysts, the acid
and basic sites mainly originate from the Zr4+ and O2−
,
respectively. The preceding ATR-IR and in situ ATR-IR tests
verify that Zr4+ of BZC can activate CvO and clarifies the
hydrogen transfer process of FUR. In addition, the NH3-IR and
HCOOH-IR spectra also demonstrate that BZC catalysts
contain a large amount of acid–base sites. Combined with rele-
vant literature,65,67 a possible mechanism based on the catalyst
for hydrogen transfer of carboxides is proposed (Scheme 1).
First, isopropanol adsorbed on the surface of the BZC catalyst
interacts with the acid–base sites (Zr4+–O2−) on the surface of
the catalyst, resulting in dissociation of isopropanol to form
Hydrogen transfer of carboxides and xylose-derived FUR over
the BZC catalyst
Inspired by the excellent catalytic performance of the BZC cata- the corresponding alkoxide and hydrogen. Meanwhile, the car-
lyst for hydrogen transfer of FUR at low temperature, the con- bonyl group of the substrate molecule is also adsorbed and
5976 | Green Chem., 2019, 21, 5969–5979
This journal is © The Royal Society of Chemistry 2019

View Article Online
Green Chemistry
Paper
Table 3 Hydrogen transfer reaction of carboxides over the BZC catalyst
Entry
1
Reactant
Main product
Temperature (°C)
80
Time (h)
7
Conv. (%)
>99
Yield (%)
>99
2
3
80
80
9
>99
>99
98.66
98.85
15
4
80
15
95.14
94.63
5
6
120
140
8
>99
>99
14
97.75
91.32
Conditions: Catalyst (0.1 g), substrate (0.67 mmol), 2-PrOH (20 mL).
activated by the acid–base sites. Further, a hydrogen transfer
reaction occurs between the dissociated alkoxide and the acti-
vated carbonyl group through a six-membered ring transition
state to form the product and acetone. Finally, the product and
acetone are desorbed from the surface of the catalyst and acid–
base sites on the surface of the catalyst are regenerated.
Conclusions
Fig. 12 Different reaction time (a) and reusability test (b) of the catalyst
for the hydrogen transfer of FUR on the performance of BZC catalyst. A simple basic zirconium carbonate (BZC) catalyst was applied
Reaction condition (a): Catalyst (0.31 g), FUR (0.67 mmol), 2-PrOH
(20 mL), 80 °C. Reaction condition (b): Catalyst (0.31 g), FUR
(0.67 mmol), 2-PrOH (20 mL), 80 °C, 5 h.
for catalyzing the hydrogen transfer reaction of carboxides
derived from biomass, which exhibits high catalytic activity at
low temperatures, especially for the conversion of FUR to FFA.
At room temperature (about 24 °C), the yield of FFA reaches
98.08% with nearly complete conversion. As the reaction temp-
erature increases to 180 °C, and the yield of FFA reaches
90.29% with 91.02% conversion within 15 minutes. The
results of ATR-IR spectroscopy and XPS indicate that BZC pos-
sesses the strongest lewis acidity of the three catalysts, which
are the reasons why BZC has the best catalytic performance.
Similarly, the NH3-IR and HCOOH-IR spectra also demonstrate
that BZC catalysts contain the largest amount of acid–base
sites among the three. Kinetic studies reveal that with the BZC
as the catalyst, the Ea value of the reaction is lower in the same
type of catalysts, which is 54.77 kJ mol−1. In addition, the
Scheme 1 Plausible reaction mechanism for hydrogen transfer of carb-
oxides with the BZC catalyst.
characterization of in situ ATR-IR provides a clearer under-
This journal is © The Royal Society of Chemistry 2019
Green Chem., 2019, 21, 5969–5979 | 5977

View Article Online
Paper
Green Chemistry
standing for the real-time dynamics of the FUR hydrogen 17 X. Zheng, X. Gu, Y. Ren, Z. Zhi and X. Lu, Biofuels, Bioprod.
transfer reaction, further contributing to the proposed mecha- Biorefin., 2016, 10, 917–931.
nism of the reaction. Overall, combined with the advantages of 18 H. S. Kim, S. K. Kim and G. T. Jeong, J. Ind. Eng. Chem.,
cost-effectiveness and simple synthesis, etc., the BZC catalyst 2018, 63, 48–56.
has a good application prospect for the hydrogen transfer of 19 A. Y. Li, A. Segalla, C. Li and A. Moores, ACS Sustainable
biomass-derived carboxides.
Chem. Eng., 2017, 5, 11752–11760.
20 Y. Nakagawa, M. Tamura and K. Tomishige, ACS Catal.,
2013, 3, 2655–2668.
21 M. J. Taylor, L. J. Durndell, M. A. Isaacs, C. M. A. Parlett,
K. Wilson, A. F. Lee and G. Kyriakou, Appl. Catal., B, 2016,
180, 580–585.
Conflicts of interest
There are no conflicts to declare.
22 L. Qi, Y. F. Mui, S. W. Lo, M. Y. Lui, G. R. Akien and
I. n. T. Horváth, ACS Catal., 2014, 4, 1470–1477.
23 A. M. R. Galletti, C. Antonetti, E. Ribechini,
M. P. Colombini, N. N. o. D. Nasso and E. Bonari, Appl.
Energy, 2013, 102, 157–162.
Acknowledgements
This work was supported by grants from the National Natural
Science Foundation of China (No. 21771086) and Natural 24 J. S. Luterbacher, J. M. Rand, D. M. Alonso, J. Han,
Science Foundation of Jilin Province, China (20180101293JC).
J. T. Youngquist, C. T. Maravelias, B. F. Pfleger and
J. A. Dumesic, Science, 2014, 343, 277–280.
25 Z. Xua, A. Cheng, X. Xing, M. Zong, Y. Bai and N. Li,
Bioresour. Technol., 2018, 262, 177–183.
26 X. Li, K. Zhang, S. Chen, C. Li, F. Li, H. Xu and Y. Fu, Green
Chem., 2018, 20, 1095–1105.
27 Y. Yang, Q. Liu, D. Li, J. Tan, Q. Zhang, C. Wang and L. Ma,
RSC Adv., 2017, 7, 16311–16318.
Notes and references
1 K. Tomishige, Y. Nakagawa and M. Tamura, Green Chem.,
2017, 19, 2876–2924.
2 M. H. Haider, N. F. Dummer, D. WKnight, R. L. Jenkins,
M. Howard, J. Moulijn, S. H. Taylor and G. J. Hutchings, 28 M. J. Gilkey and B. Xu, ACS Catal., 2016, 6, 1420–1436.
Nat. Chem., 2015, 7, 2345.
3 L. Gao, Y. Bao, S. Gan, Z. Sun, Z. Song, D. Han, F. Li and
L. Niu, ChemSusChem, 2018, 11, 2547–2553.
29 H. P. Winoto, Z. A. Fikri, J. M. Ha, Y. K. Park, H. Lee,
D. J. Suh and J. Jae, Appl. Catal., B, 2019, 241, 588–597.
30 P. N. Romano, J. M. A. R. Almeida, Y. Carvalho, P. Priecel,
E. F. Sousa-Aguiar and J. A. Lopez-Sanchez, ChemSusChem,
2016, 9, 3387–3392.
31 Q. Xu, X. Li, T. Pan, C. Yu, J. Deng, Q. Guo and Y. Fu, Green
Chem., 2016, 18, 1287–1294.
32 F. Ye, D. Zhang, T. Xue, Y. Wang and Y. Guan, Green Chem.,
2014, 16, 3951–3957.
4 A. H. Valekar, 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.
5 R. Fang, R. Luque and Y. Li, Green Chem., 2017, 19, 647–
655.
6 Q. Hou, M. Zhen, L. Liu, Y. Chen, F. Huang, S. Zhang,
W. Li and M. Ju, Appl. Catal., B, 2018, 224, 183–193.
7 B. Liu and Z. Zhang, ChemSusChem, 2016, 9, 2015–2036.
33 P. Zhang, C. Liu, L. Chen, J. Chen, Y. Guan and P. Wu,
J. Catal., 2017, 351, 10–18.
8 J. Dai, L. Zhu, D. Tang, X. Fu, J. Tang, X. Guo and C. Hu, 34 J. Tan, J. Cui, T. Deng, X. Cui, G. Ding, Y. Zhu and Y. Li,
Green Chem., 2017, 19, 1932–1939. ChemCatChem, 2015, 7, 508–512.
9 H. Li, S. Saravanamurugan, S. Yang and A. Riisager, Green 35 Z. Wei, J. Lou, C. Su, D. Guo, Y. Liu and S. Deng,
Chem., 2016, 18, 726–734. ChemSusChem, 2017, 10, 1720–1732.
10 F. Yu, J. Thomas, M. Smet, W. Dehaen and B. F. Sels, Green 36 P. Pongracz, B. Bartal, L. Kollar and L. T. Mika,
Chem., 2016, 18, 1694–1705. J. Organomet. Chem., 2017, 847, 140–145.
11 Z. Chen, W. D. Reznicek and C. Wan, ACS Sustainable 37 Z. Tian, C. Liu, Q. Li, J. Hou, Y. Li and S. Ai, Appl. Catal., A,
Chem. Eng., 2018, 6, 6910–6919. 2015, 506, 134–142.
12 M. D. Smith, C. M. Cai, X. Cheng, L. Petridis and 38 Z. Tian, Q. Li, J. Hou, L. Pei, Y. Li and S. Ai, J. Catal., 2015,
J. C. Smith, Green Chem., 2018, 20, 1612–1620. 331, 193–202.
13 C. V. Nguyen, D. Lewis, W. H. Chen, H. W. Huang, 39 K.-T. Li and R.-H. Yen, Nanomaterials, 2018, 8, 158.
Z. A. ALOthman, Y. Yamauchi and K. C. W. Wu, Catal. 40 V. K. Velisoju, N. Guttaa, J. Tardio, S. K. Bhargava,
Today, 2016, 278, 344–349.
14 T. Guo, X. Li, X. Liu, Y. Guo and Y. Wang, ChemSusChem,
2018, 11, 2758–2765.
K. Vankudoth, A. Chatla, S. Medak and V. Akula, Appl.
Catal., A, 2018, 550, 142–150.
41 M. Grilc and B. Likozar, Chem. Eng. J., 2017, 330, 383–397.
15 C. Zhu, Q. Liu, D. Li, H. Wang, C. Zhang, C. Cui, L. Chen, 42 Z. Tian, Q. Li, Y. Li and S. Ai, Catal. Commun., 2015, 61, 97–
C. Cai and L. Ma, ACS Omega, 2018, 3, 7407–7417. 101.
16 D. Li, Q. Liu, C. Zhu, H. Wang, C. Cui, C. Wang and L. Ma, 43 L. Jiang, P. Zhou, C. Liao, Z. Zhang and S. Jin,
J. Energy Chem., 2019, 30, 34–41.
ChemSusChem, 2018, 11, 959–964.
5978 | Green Chem., 2019, 21, 5969–5979
This journal is © The Royal Society of Chemistry 2019

View Article Online
Green Chemistry
Paper
44 S. Ishikawa, D. R. Jones, S. Iqbal, C. Reece, D. J. Morgan, 62 J. He, S. Yang and A. Riisager, Catal. Sci. Technol., 2018, 8,
D. J. Willock, P. J. Miedziak, J. K. Bartley, J. K. Edwards, 790–797.
T. Murayama, W. Ueda and G. J. Hutchings, Green Chem., 63 Z. Gao, L. Yang, G. Fan and F. Li, ChemCatChem, 2016, 8,
2017, 19, 225–236. 3769–3779.
45 R. Zhang, Y. Ma, F. You, T. Peng, Z. He and K. Li, 64 H. Li, J. He, A. Riisager, S. Saravanamurugan, B. Song and
ScienceDirect, 2017, 42, 25185–25194. S. Yang, ACS Catal., 2016, 6, 7722–7727.
46 Z. Xiao, H. Zhou, J. Hao, H. Hong, Y. Song, R. He, K. Zhi 65 J. Song, B. Zhou, H. Zhou, L. Wu, Q. Meng, Z. Liu and
and Q. Liu, Fuel, 2017, 193, 322–330. B. Han, Angew. Chem., Int. Ed., 2015, 54, 9399–9403.
47 J. Song, L. Wu, B. Zhou, H. Zhou, H. Fan, Y. Yang, Q. Meng 66 H. Li, Z. Fang, J. He and S. Yang, ChemSusChem, 2017, 10,
and B. Han, Green Chem., 2015, 17, 1626–1632. 681–686.
48 J. He, H. Li, A. Riisager and S. Yang, ChemCatChem, 2018, 67 Y. Sha, Z. Xiao, H. Zhou, K. Yang, Y. Song, N. Li,
10, 430–438.
R. He, K. Zhi and Q. Liu, Green Chem., 2017, 19, 4829–
4837.
49 R. Cohen, C. R. Graves, S. T. Nguyen, J. M. L. Martin and
M. A. Ratner, J. Am. Chem. Soc., 2004, 126, 14796–14803.
50 R. Cohen, C. R. Graves, S. T. Nguyen, J. M. L. Martin and
M. A. Ratner, J. Am. Chem. Soc., 2004, 14796–14803.
51 Y. Zhu, S. Jaenicke and G. K. Chuah, J. Catal., 2003, 218,
396–404.
68 H. Liu, G. Zhang, X. Wang, L. Zhu, C. Feng, B. Liu and
D. Xu, J. Sol-Gel Sci. Technol., 2015, 76, 482–491.
69 B. DjurW, S. Pickering, D. McGarry, P. Glaude,
R. Tambuyser and K. Schuster, Ceram. Int., 1995, 21, 195–
206.
52 X. Tang, H. Chen, L. Hu, W. Hao, Y. Sun, X. Zeng, L. Lin 70 J. Datka, B. Gil and A. Kubacka, Zeolites, 1995, 15, 501–506.
and S. Liu, Appl. Catal., B, 2014, 147, 827–834.
53 X. Tang, L. Hu, Y. Sun, G. Zhao, W. Hao and L. Lin, RSC
Adv., 2013, 3, 10277–10284.
54 R. Wang, J. Wang, H. Zi, Y. Xia, H. Wang and X. Liu, Mol.
Catal., 2017, 441, 168–178.
71 Q. Zhang, Y. Tan, G. Liu, J. Zhang and Y. Han, Green Chem.,
2014, 16, 4708–4715.
72 K. Vankudoth, N. Gutta, V. K. Velisoju, S. Mutyala,
H. P. Aytam and V. Akula, Catal. Sci. Technol., 2017, 7,
3399–3407.
55 J. Wang, K. Okumura, S. Jaenicke and G.-K. Chuah, Appl. 73 K. Vankudoth, A. H. Padmasri, R. Sarkari, V. K. Velisoju,
Catal., A, 2015, 493, 112–120.
56 A. Corma, M. E. Domine, L. Nemeth and S. Valencia, J. Am.
Chem. Soc., 2002, 124, 3194–3195.
57 A. Osatiashtiani, A. F. Lee and K. Wilson, J. Chem. Technol.
Biotechnol., 2017, 92, 1125–1135.
N. Gutta, N. K. Sathu, C. N. Rohita and V. Akula, New J.
Chem., 2017, 41, 9875–9883.
74 V. Krishna, G. Naresh, V. V. Kumar, R. Sarkari,
A. H. Padmasri and A. Venugopal, Appl. Catal., B, 2016,
193, 58–66.
58 L. Fukun, L. Zhangmin, F. L. John, M. Jiali, S. Changhua, 75 S. Zhou, G. Chen, X. Feng, M. Wang, T. Song, D. Liu, F. Lu
C. Yuan, J. Lilong, L. Jinxing and L. Xuehui, Ind. Eng.
Chem. Res., 2018, 57, 10126–10136.
59 F. Wang and Z. Zhang, ACS Sustainable Chem. Eng., 2017, 5,
942–947.
60 J. He, H. Li, Y. Lu, Y. Liu, Z. Wu, D. Hu and S. Yang, Appl.
Catal., A, 2016, 510, 11–19.
61 R. López-Asensio, J. A. Cecilia, C. P. Jiménez-Gómez,
and H. Qi, Green Chem., 2018, 20, 3593–3603.
76 J. Köchermann, J. Schreiber and M. Klemm, ACS
Sustainable Chem. Eng., 2019, 7, 12323–12330.
77 A. Chatterjee, X. Hu and F. L.-Y. Lam, Fuel, 2019, 239, 726–
736.
78 B. Cai, X. Zhou, Y. Miao, J. Luo, H. Pan and Y. Huang, ACS
Sustainable Chem. Eng., 2017, 5, 1322–1331.
C. García-Sancho, R. Moreno-Tost and P. Maireles-Torres, 79 M. Chia and J. A. Dumesic, Chem. Commun., 2011, 47,
Appl. Catal., A, 2018, 556, 1–9.
12233–12235.
This journal is © The Royal Society of Chemistry 2019
Green Chem., 2019, 21, 5969–5979 | 5979