Zr-DBS with Sulfonic Group: A Green and Highly Efficient Catalyst for Alcoholysis of Furfuryl Alcohol to Ethyl Levulinate

Article abstract of DOI:10.1007/s10562-020-03516-1

The alcoholysis of furfuryl alcohol (FA) produce ethyl levulinate (EL) plays a crucial role in the field of biomass conversion. In this work, a novel Zr-base catalyst with sulfonic groups in its structure was prepared by the co-precipitation of sodium dodecyl benzene sulfonate and ZrOCl₂ (Zr-DBS) under non-toxic conditions. It was found that Zr-DBS has an excellent catalytic performance for this reaction and an EL yield of 95.27% could be achieved. Besides, Zr-DBS could be easily separated from the reaction system and reused at least four times without a significantly decrease in activity. Meanwhile, Zr-DBS was characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption–desorption, inductively coupled plasma optical emission spectroscopy (ICP-OES) and Temperature-programmed desorption of ammonia (NH₃-TPD). The main reason for the high catalytic activity of the Zr-DBS was that the synergetic effects of Lewis and Br?nsted acid sites and appropriate textural properties. Graphic Abstract: [Figure not available: see fulltext.]

Full text of DOI:10.1007/s10562-020-03516-1

Catalysis Letters
https://doi.org/10.1007/s10562-020-03516-1
Zr‑DBS with Sulfonic Group: A Green and Highly Efcient Catalyst
for Alcoholysis of Furfuryl Alcohol to Ethyl Levulinate
Xiaoning Li1 · Yehui Li1 · Xiang Wang1 · Qingrui Peng1 · Wei Hui1 · ·Aiyun Hu1 · Haijun Wang1
Received: 28 October 2020 / Accepted: 23 December 2020
© The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature 2021
Abstract
The alcoholysis of furfuryl alcohol (FA) produce ethyl levulinate (EL) plays a crucial role in the feld of biomass conversion.
In this work, a novel Zr-base catalyst with sulfonic groups in its structure was prepared by the co-precipitation of sodium
dodecyl benzene sulfonate and ZrOCl2 (Zr-DBS) under non-toxic conditions. It was found that Zr-DBS has an excellent
catalytic performance for this reaction and an EL yield of 95.27% could be achieved. Besides, Zr-DBS could be easily sepa-
rated from the reaction system and reused at least four times without a signifcantly decrease in activity. Meanwhile, Zr-DBS
was characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray difraction (XRD), scanning electron
microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption, inductively coupled plasma opti-
cal emission spectroscopy (ICP-OES) and Temperature-programmed desorption of ammonia (NH3-TPD). The main reason
for the high catalytic activity of the Zr-DBS was that the synergetic efects of Lewis and Brønsted acid sites and appropriate
textural properties.
Graphic Abstract
Keywords Furfuryl alcohol · Alcoholysis · Zr-DBS · Ethyl levulinate
Supplementary information The online version of this article
1 Introduction
(https://doi.org/10.1007/s10562-020-03516-1) contains
supplementary material, which is available to authorized users.
The gradual decrease in fossil fuels indicates the need to fnd
wide variety of renewable and alternative energy sources to
meet the increase of energy demand. Therefore, researchers
around the world have paid more attention to the technology
* Haijun Wang
wanghj@jiangnan.edu.cn
1
School of Chemical and Material Engineering, Jiangnan
University, Wuxi 214122, China
Vol.:(0123456789)
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X. Li et al.
of utilizing various cheap and available substances, such as
convert biomass and waste CO2 into value-added chemicals
[1, 2]. Among them, as one of the most abundant renewable
energy sources available, biomass is not only cheap and easy
to obtain, but also uses agricultural waste, and is regarded
as the raw material of green chemistry in the future [3]. So
far, a variety of value-added chemicals can be obtained from
biomass, such as furfural, furfuryl alcohol (FA), levulinic
acid (LA), alkyl levulinate (AL), γ-valerolactone (GVL), etc.
[4–8]. Among them, AL is a series of short-chain biomass
platform chemicals, and it has many applications in industry,
including biofuel additive, lubricants, spices, plasticizing
and favoring agents [9–12]. Owing to its two functional
groups, ester group and carbonyl group, it can be converted
into other more valuable biomass platform chemicals
through substitution, addition, condensation, hydrolysis and
other reactions, such as the conversion of ethyl levulinate to
GVL by Meerwein–Ponndorf–Verley reaction [13].
EL. The catalyst has the advantages of abundant and easily
obtained raw materials, simple preparation process without
excessive energy loss, non-toxic solvent and cost-efective.
2 Experimental Section
2.1 Chemicals
Furfuryl alcohol, methyl levulinate, ethyl levulinate (EL),
butyl levulinate, levulinic acid, ZrOCl2·8H2O, Ti(SO4)2,
SDBS, Sodium dodecyl sulfonate (SDS), methanol, ethanol,
iso-propanol, 1-butanol, naphthalene and deionized water
are of analytical grade and used without further treatment.
The esterifcation of iso-propanol and LA is catalyzed
by HCl to synthesize isopropyl levulinate (IPL), which is
then purifed by distillation. The purity was analyzed by gas
chromatography-fame ionization detection (GC-FID) and
proved to be greater than 99%.
There are three main ways to produce AL: direct alco-
holysis of biomass, esterifcation of LA and alcoholysis of
furfuryl alcohol [14, 15]. The most common raw materials
for direct alcoholysis from biomass are cellulose, glucose
and fructose. The problems faced by this process are low
yield of target product, a lot of impurities and difcult sepa-
ration. Direct esterifcation from LA is a typical acid-cata-
lyzed reaction, but LA is expensive which makes it cannot
be widely used. The alcoholysis of FA is an acid-catalyzed
reaction of FA and alcohol. Witnessed tremendous progress
in alcoholysis in recent years, it has signifcant advantages
compared with the conventional hydrolysis, such as inhibit-
ing the formation of humins as well as increasing the reac-
tion rate and product yield [14]. In the last decade, various
catalysts have been gradually applied to this reaction, such
as zeolite, metal trifates, metal salt, metal oxides, ionic liq-
uid, resin, graphene, arylsulfonic acid functionalized hol-
low mesoporous carbon spheres, supported TPA catalysts,
sulfonated carbon materials, etc. [16–24].
2.2 Catalyst Preparation
The preparation method of the as-prepared catalyst is
referred to the previous literature and is modifed [30]. In a
general procedure, 1 mmol SDBS and 2 mmol ZrOCl2·8H2O
were dissolved in deionized water (25 mL) respectively.
Then, the ZrOCl2·8H2O solution was dropwise added to
the stirring solution of SDBS. After that the mixture was
stirred vigorously for 5 h and then aged for 5 h at room
temperature. The white precipitate obtained was isolated by
centrifugation and then washed several times with water and
ethanol, and fnally dried at 60 °C under vacuum for 14 h,
denoted as Zr-DBS. For comparison, other catalysts were
prepared using the same raw material molar ratio as Zr-DBS
and similar methods. One was to use Ti(SO4)2 instead of
ZrOCl2·8H2O to coordinate with SDBS, named Ti-DBS and
the other was to use SDS instead of SDBS to coordinate with
ZrOCl2·8H2O, named Zr-DS.
Zr-containing organic–inorganic hybrid materials have
been applied in several catalytic reaction in the feld of
biomass conversion, such as using phytic acid and humic
acid as building blocks were reported for the production of
γ-valerolactone from ethyl levulinate [13, 25]. To date, sev-
eral Zr-based catalysts have been reported for the alcoholysis
of FA to AL, including ZPS, SZF, PW12/ZrO2-Si(Et)Si-NTs
and MZM [26–29]. However, the complex and time-con-
suming preparation and high energy consumption are still
serious problems. Therefore, it is crucial to fnd an efcient
and cost-efective catalyst in the present research. As a com-
mon anionic surfactant, Sodium dodecylbenzene sulfonate
(SDBS) has a sulfonic group in its structure, which can coor-
dinate with metals. Herein, we use co-precipitation method
to synthesizes SDBS with ZrOCl2 in water to synthesize
a catalyst for the alcoholysis of FA in ethanol to produce
2.3 Catalyst Characterization
Fourier transform infrared (FT-IR) spectra were detected
with a Nicolet 360 FT-IR instrument (KBr pellet) in the range
of 4000–600 cm−1. X-ray difraction (XRD) patterns were
recorded on a Bruker D8 Advance difractometer with Cu Ka
radiation and 2θ recorded from 5 to 90° at 30 kV and10 mA.
Scanning electron microscopy (SEM) images were obtained
using a HITACHI S-4800 scanning electron microscope at
3 kV. Transmission electron microscopy (TEM) measure-
ment was performed on a JEOL JEM-2100 microscope at
200 kV. The N2 adsorption–desorption isotherm was measured
using a Micromeritics ASAP 2020 instrument, samples were
degassed at 120 °C for 12 h in a vacuum before N2 absorption.
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Zr‑DBS with Sulfonic Group: A Green and Highly Efcient Catalyst for Alcoholysis of Furfuryl…
Temperature-programmed desorption of ammonia (NH3-TPD)
was performed on Micromeritics AutoChem II 2920 Chem-
isorption analyzer, the sample (50 mg) was charged into quartz
reactor and preheated at 300 °C for 1 h at a rate of 10 °C min−1
under a fow of He (50 cm3 min−1). Then the temperature
was dropped to 50 °C, NH3 (50 cm3 min−1) was pulsed into
the reactor in He fow until the acid sites was saturated. The
absorbed NH3 was removed with He and the temperature was
raised from 60 to 700 °C at a rate of 10 °C min−1 after waiting
for baseline stabilization. The contents of Zr, S, C in Zr-DBS
and the concentration of Zr in the reaction solution were deter-
mined by inductively coupled plasma optical emission spec-
troscopy (ICP-OES) which performed on PE Optima 8000.
physically adsorbed water [31, 32]. A multitude of bands
in the region 2840–2930 cm−1 was assigned to the stretch-
ing vibrations of aliphatic C-H and band in 1600 cm−1 was
assigned to the vibrations of benzene [33, 34]. The band
at 1460 cm−1 was due to C=C stretching vibration in aro-
matic carbon. The sample also had a band at about 670 cm−1
arose from –C–S– bonds vibration of sulfonic groups [35].
Both Zr-DBS and SDBS showed the characteristic bands of
S=O symmetric stretching vibration of sulfonic groups, and
the as-prepared catalyst showed the characteristic absorp-
tion peaks of sulfonate anions at 1156 cm−1 and 1036 cm−1
[34–36]. Compared with the FT-IR spectrum of SDBS, the
diference in the wavenumber of the vibration of the sul-
fonate anion is narrowed, indicating that the sulfonate was
coordinated with Zr4+ ions [37, 38].
2.4 Alcoholysis of FA to EL
The XRD pattern of the Zr-DBS are shown in Fig. 1b.
Obviously, the Zr-DBS had a broad difraction peak, indi-
cating that Zr-DBS was amorphous. Generally speaking,
the presence of weak coordination groups in the catalyst
structure will lead to low crystallinity, indicating that the
low crystallinity of Zr-DBS comes from the only weak
coordination groups (sulfonic groups) in the structure [39].
The textural properties of Zr-DBS were characterized by N2
adsorption–desorption isotherm. It could be seen that Zr-
DBS belonged to typical type IV isotherms (Fig. 1c), indi-
cating Zr-DBS is a mesoporous material with irregular pore
structure, which was in consistent with the pore size distri-
bution (Fig. 1d). The porosity of the Zr-DBS was caused by
the gaps between the aggregated particles (shown in Fig. 2a).
Besides, Brunauer–Emmett–Teller (BET) surface area and
pore volume and the average pore size calculated from N2
adsorption–desorption were 6.24 m2 g−1, 0.033 cm3 g−1 and
21.65 nm, respectively. When the relative pressure (P/P0) of
N2 adsorption is as low as 0.01, the N2 adsorption capacity
of Zr-DBS is very low in the N2 adsorption–desorption iso-
therm, indicating that the number of micropores in Zr-DBS
is very limited [40]. This can also be seen from the SEM
image (Fig. 2a). Although the specifc area and pore volume
is limited, its large pore size helped to enhance the difusion
of FA to the active center of the as-prepared catalyst and
then promoted the reaction.
The alcoholysis reaction from FA to EL was carried out in
a 25 mL Tefon-lined stainless-steel reactor equipped with a
magnetic stirrer. In a typical procedure, FA (1 mmol), ethanol
(10 mL), and the catalyst (0.2 g) were added into the reactor.
The reactor was sealed and placed into a preheated oil-bath at a
known temperature for the desired time. At the end of the reac-
tion, the reactor was cooled to room temperature and the liquid
samples were collected and analyzed by gas chromatography
(GC 9790) using naphthalene as the internal standard, and
identifcation of the liquid products was identifed by GC–MS
(ULTRA QP2010). The conversion of FA and yield of EL
were calculated by the formula following:
Moles of EL formed
YieldofEL =
× 100%
(1)
Moles of FA used
Moles of FA converted
Moles of FA used
ConversionofFA =
× 100%
(2)
2.5 Leaching Test and Reusability Test
To investigate the heterogeneity of the catalyst, the catalyst
was removed from the reaction mixture after 1 h and then the
reaction was continued. The Zr specie leached into the reaction
mixture were analyzed by ICP-OES. In the reusability tests,
the spent catalyst was recovered by centrifugation and washed
three times with ethanol. After drying under vacuum at 60 °C
for 14 h, the catalyst was reused for the next run.
Meantime, the surface morphology and internal compo-
sition of the prepared catalyst were observed by SEM and
TEM, the images are shown in Fig. 2a and b. It can be seen
that Zr-DBS has no uniform shape, and the gap between the
aggregated particles leads to the porosity of the catalyst,
which is consistent with the XRD result [30].
3 Results and Discussion
3.2 Catalyst Screening
3.1 Catalyst Characterization
The importance of an excellent catalyst for the alcoholysis
of FA to EL is conspicuous. As shown in Table 1, in the
absence of catalyst, no reaction occurred (Table 1, entry 1).
The FT-IR spectrum of SDBS and Zr-DBS were shown
in Fig. 1a. Strong peaks at 3418 cm−1 was ascribed to the
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X. Li et al.
Fig. 1 Characterization of Zr-DBS. a FT-IR spectra, b Powder XRD pattern, c N2 adsorption–desorption isotherm, d pore size distribution
Fig. 2 SEM image (a) and TEM image (b) of Zr-DBS
When Zr-DBS catalyst was used for this reaction, it was not
difcult to fnd that Zr-DBS possessed the highest activ-
ity with 95.27% EL yield at 150 °C for 2 h (Table 1, entry
2). In contrary, Ti-DBS was little activity for this reaction
(Table 1, entry 3). For comparison, Zr-DS, having a similar
structure to Zr-DBS, was obtained a moderate yield of EL
(Table 1, entry 4). Afterwards, SDBS and SDS were used
to catalyze the reaction, little EL yield could be observed
(Table 1, entries 5 and 6). These results demonstrated that
Zr was the activity center for the alcoholysis of FA to EL and
1 3

Zr‑DBS with Sulfonic Group: A Green and Highly Efcient Catalyst for Alcoholysis of Furfuryl…
Table 1 Comparison of diferent catalysts for the reaction of alcoho-
over Zr-DBS (Fig. 3). As shown in Fig. 3, the yield EL
and the conversion of FA continuously increased when
the temperature increased from 120 to 150 °C, which sug-
gested that the alcoholysis of FA to EL was easier to pro-
ceed at high temperature. However, the FA conversion only
slightly increased and the EL yield began to decrease when
the temperature rose to 160 °C, which may be because the
high temperature promoted the side reaction. Therefore,
150 °C was the optimal reaction temperature. Obviously,
the yield of EL and conversion of FA increased rapidly as
the reaction time increased from 1 to 2 h. Although the
conversion rate of FA remains constant, when the reaction
time is extended to 4 h, the EL yield began to decreased,
indicating that 2 h is the most suitable reaction time to
obtain the target product. As a result, 150 °C and 2 h were
the best reaction conditions.
lysis of FA to EL
Entry Catalyst Tem-
Time (h) ConversionFA
(%)
YieldEL (%)
perature
(°C)
1
2
3
4
5
6
Nonea
0
0
2
2
2
2
2
0.96
98.83
32.74
90.28
3.64
0
Zr-DBSa 150
Ti-DBSa 150
Zr-DSa 150
SDBSa 150
95.27
10.34
56.32
0.97
1.63
SDSa
150
30.65
aReaction condition: FA (0.098 g, 1 mmol), catalyst 0.2 g, ethanol
10 mL
the addition of a sulfonic group could help to achieve high
EL yield. Therefore, Zr-DBS was considered as the most
suitable catalyst in the next study. The reason for the high
activity of the catalyst will be discussed below. Meantime,
the results of reaction conditions and activities of the pre-
sent catalyst and other reported catalytic systems have been
summarized in Table S2. Compared with other alcoholysis
catalysts, the Zr-DBS catalyst prepared in this study can pro-
vide relatively high conversion and yield (both higher than
95%). In terms of reaction conditions and the cost of catalyst
preparation materials, Zr-DBS catalyst has obvious advan-
tages compared with other catalysts, especially the inherent
sulfonic groups in SDBS could serve as Brønsted acidic sites
avoiding the use of hazardous sulfonating agents.
3.4 Efect of the Amount of Catalyst
The efect of the Zr-DBS dosage was investigated in the
range of 0.1 to 0.4 g and the results have presented in
Fig. 4. It was obvious that the conversion of FA and the
yield of EL increased from 89.18 and 82.26% to 98.83
and 95.27%, respectively. When the amount of catalyst
increased from 0.1 to 0.2 g, the conversion of FA and the
yield of EL increased rapidly, which could be attributed
to more available active sites. However, further increasing
the amount of catalyst led to a slight decrease in EL yield.
It may be due to the excessive amount of catalyst, result-
ing in poor dispersion of heterogeneous catalyst particles,
which has a negative impact on the mass transfer of the
reaction. Hence, 0.2 g of the Zr-DBS would be the best
choice in the next experiments.
3.3 Efect of Reaction Temperature and Time
As we all known, the reaction temperature and time are
critical to the reaction. Consequently, the alcoholysis of
FA to EL was performed at diferent temperature and time
Fig. 3 Efect of reaction time and temperature on the FA conversion (a) and EL yield (b). Reaction conditions: FA (0.098 g, 1 mmol), catalyst
0.2 g, ethanol 10 mL
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X. Li et al.
Fig. 5 Efect of catalyst with diferent substrates. Reaction condi-
tions: 1 FA (0.098 g, 1 mmol), catalyst 0.2 g, ethanol 10 mL, reaction
temperature 150 °C, reaction time 2 h
Fig. 4 Efect of catalyst amount. Reaction conditions: FA (0.098 g,
1 mmol), 10 mL ethanol, reaction temperature 150 °C, reaction time
2 h
The stability of the Zr-DBS catalyst used for the alco-
holysis of FA was also checked under the optimal reaction
conditions. Although the EL yield in the reaction system
decreased systematically after the catalyst was reused 4
times (Fig. 6b), the catalyst remained active in each cycle,
indicating that the Zr-DBS in the reaction was stable. The
decrease in EL yield in the recycling run probably due to
the deposition of carbonaceous products produced by the
reaction process deactivating the catalyst surface [41]. The
Zr-DBS used after four cycles was characterized by FT-IR,
XRD and SEM. It can be seen from Fig. 7 that the amor-
phous morphology and microstructure of the recovered Zr-
DBS remain basically unchanged compared with the fresh
catalyst. Meantime, ICP-OES result showed that less than
2.8 ppm of Zr specie leached into the fltrate after the fourth
round of reaction, indicating that a small amount of Zr active
sites were lost, resulting in a slight decrease in catalytic per-
formance. These fndings demonstrate that the Zr-DBS can
be recovered and reused very well in the alcoholysis of fur-
furyl alcohol and the active site of the Zr-DBS was insoluble
in the reaction system.
3.5 Catalytic Efect of Zr‑DBS on Diferent
Substrates
Due to the high activity of Zr-DBS for the alcoholysis of FA
to EL, other alcohols were also used as substrate to produce
other AL. As displayed in Fig. 5, methanol and 1-butanol
were easily converted to corresponding levulinate in 2 h with
yields of 89.76% and 80.89% respectively. Hence, metha-
nol and 1-butanol could achieve good results like ethanol.
On the contrary, only 73.39% furfuryl alcohol conversion
and 63.84% IPL yield could be observed at the same reac-
tion conditions because of the steric hindrance of isopropyl
[41]. These discussions have fully demonstrated that the Zr-
DBS has an excellent catalytic activity for the production of
AL from the alcoholysis of furfuryl alcohol and diferent
alcohols.
3.6 The Leaching Test and Reusability
of the Catalyst
To investigate the stability and reusability of the Zr-DBS, a
leaching test and recycle experiment were conducted under
the optimal reaction conditions, respectively. As shown in
Fig. 6a, after the removal of Zr-DBS, no further reaction
proceeded, and the EL yield remained at about 60.02%, indi-
cating that there are no or few active sites in the reaction
system. On the contrary, as the catalyst remains in the reac-
tion system, the yield of EL increases steadily. The ICP-OES
results showed that the Zr/S molar ratio in fresh and spent
Zr-DBS was about 2:1, and there was no signifcant compo-
sitional change in the fltered sample, implying that a little
active species was leached into the reaction mixture and the
heterogeneous character of Zr-DBS (Table 2).
3.7 Explanation of the High Activity of Zr–DBS
From the previous analysis, it can be seen that Zr-DBS has
a high activity to the alcoholysis reaction of FA to produce
EL. Firstly, the total acidity of Zr-DBS was checked by
NH3-TPD (Fig. 8). It can be seen, there are two desorption
peaks located at 133 °C and 473 °C, indicating the coexist-
ence of weak and strong acid sites and the acidity amounts
are 0.146 and 1.04 mmol g−1, respectively. The frst peak
corresponds to the weak acidic site. Since there were almost
no hydroxyls in Zr-DBS, we consider that the weak acidic
sites mainly derived from the Zr4+. In general, the metal ions
1 3

Zr‑DBS with Sulfonic Group: A Green and Highly Efcient Catalyst for Alcoholysis of Furfuryl…
Fig. 6 Leaching test of Zr-DBS for the alcoholysis of FA to EL (a) and recycle experiment of the Zr-DBS (b). Reaction conditions: FA (0.098 g,
1 mmol), catalyst 0.2 g, ethanol 10 mL, reaction temperature 150 °C, reaction time 2 h
Table 2 Composition of Zr,
S, C in Zr-DBS determined by
ICP-OES
appropriate texture properties result in high catalytic activ-
ity of Zr-DBS.
Catalysts Content (wt.%)
Zr
S
C
Fresh
Spent
24.08 4.32 32.57
23.44 4.16 34.05
3.8 Plausible Mechanism
According to literatures, multiple routes for producing AL
from FA have been proposed, including the key interme-
diate EMF. Combining the experiment results and some
previous reports [43, 44], we proposed a possible reaction
mechanism of Zr-DBS catalyzing FA to produce EL through
alcoholysis (Scheme 1). Firstly, the hydroxyl groups of FA
are protonated by acidic groups and then attacked by etha-
nol to form EMF. Subsequently, EMF and ethanol generate
2-ethoxy-5-methylene-2,5-dihydrofuran through 1,4-addi-
tion. In the process of 1,4-addition, an ethanol molecule is
released, and then under the action of water molecules, the
ring is opened and subsequent tautomerized leading to the
generation of EL.
in the metal–ligand coordination polymers exhibit Lewis
acidity [42]. The second peak relate to the strong acid site
originated from the sulfonic group showing Brønsted acidity.
The high catalytic activity of Zr-DBS can be attributed to the
synergistic efect of these two acid sites.
In addition, the structure of the catalyst will also afect
the activity of the catalyst. The N2 adsorption–desorption
isotherm and pore size distribution of Zr-DBS has shown
in Fig. 1c and d. The large pore diameter and pore volume
were helpful for increasing the difusion of the reactants to
the activity center, and thus promoted the reaction with a
high activity. Therefore, a large number of acid sites and
Fig. 7 The characterization of the Zr-DBS after reused for four times. a FT-IR spectrum, b XRD pattern and c SEM image
1 3

X. Li et al.
mechanism of FA alcoholysis to EL is proposed. As a con-
sequence of the low-cost and pollution-free characteriza-
tion of the catalyst, Zr-DBS has potential applications in
the catalytic conversion of biomass.
Acknowledgements We thank Postgraduate Research & Practice Inno-
vation Program of Jiangsu Province (No. KYCX20_1777)
Compliance with Ethical Standards
Conflict of interest The authors declare no confict of interests.
References
Fig. 8 NH3-TPD of Zr-DBS
1. Hui W, He XM, Xu XY et al (2020) Highly efcient cycloaddi-
tion of diluted and waste CO2 into cyclic carbonates catalyzed by
porous ionic copolymers. J CO2 Util 36:169–176
2. Gallezot P (2012) Conversion of biomass to selected chemical
products. Chem Soc Rev 41:1538–1558
3. Antunes MM, Lima S, Neves P et al (2015) One-pot conversion
of furfural to useful bio-products in the presence of a Sn, Al-
containing zeolite beta catalyst prepared via post-synthesis routes.
J Catal 329:522–537
4. Hui W, Zhou Y, Dong Y et al (2019) Efcient hydrolysis of hemi-
cellulose to furfural by novel superacid SO4H-functionalized
ionic liquids. Green Energy Environ 4:49–55
5. Wang T, Hu A, Xu G et al (2019) Porous Zr–thiophenedicarbo-
xylate hybrid for catalytic transfer hydrogenation of bio-based
furfural to furfuryl alcohol. Catal Lett 149:1845–1855
6. Wang K, Liu Y, Wu W et al (2020) Production of levulinic acid
via cellulose conversion over metal oxide-loaded MOF catalysts
in aqueous medium. Catal Lett 150:322–331
7. Tian Y, Zhang R, Zhao W et al (2020) A new sulfonic acid-func-
tionalized organic polymer catalyst for the synthesis of biomass-
derived alkyl levulinates. Catal Lett. https://doi.org/10.1007/s1056
2-020-03253-5
8. Chen H, Xu Q, Li H et al (2020) Catalytic transfer hydrogenation
of ethyl levulinate to γ-valerolactone over Ni supported on equi-
librium fuid-catalytic-cracking catalysts. Catal Lett. https://doi.
org/10.1007/s10562-020-03326-5
Scheme 1 Plausible mechanism of acid-catalyzed conversion of FA
into EL over Zr-DBS
9. Zhao D, Prinsen P, Wang Y et al (2018) Continuous fow alcoho-
lysis of furfuryl alcohol to alkyl levulinates using zeolites. ACS
Sustain Chem Eng 6:6901–6909
4 Conclusions
10. Rao BS, Kumari PK, Dhanalakshmi D, Lingaiah N (2017) Selec-
tive conversion of furfuryl alcohol into butyl levulinate over zinc
exchanged heteropoly tungstate supported on niobia catalysts. Mol
Catal 427:80–86
In summary, a novel Zr-base catalyst (Zr-DBS) has been
synthesized and used as a heterogeneous catalyst for the
alcoholysis of FA to produce EL. The characterization
and experimental results show that Zr-DBS has excel-
lent catalytic activity for the preparation of EL from FA.
Under optimized reaction conditions, the FA conversion
is 98.83% and the EL yield is 95.27%. The high activity of
the catalyst was attributed to the synergistic efect of the
Lewis acid sites derived from Zr4+ and the Brønsted acid
sites originated from sulfonic group. Besides, the Zr-DBS
catalyst could be reused four times without signifcantly
reduce of catalytic activity. Finally, the possible reaction
11. Zhao D, Wang Y, Delbecq F, Len C (2019) Continuous fow con-
version of alkyl levulinates into Γ-valerolactone in the presence
of Ru/C as catalyst. Mol Catal 475:110456
12. Zhang Y, Tong X, Yu L et al (2019) Highly efcient catalytic
valorization of biomass-derived hexoses and furfuryl alcohol in
the presence of polymer-based catalysts. Green Energy Environ
4:424–431
13. Song J, Zhou B, Zhou H et al (2015) Porous zirconium-phytic acid
hybrid: a highly efcient catalyst for meerwein-ponndorf-verley
reductions. Angew Chem Int Ed 54:9399–9403
14. Zhu S, Guo J, Wang X et al (2017) Alcoholysis: a promising tech-
nology for conversion of lignocellulose and platform chemicals.
Chemsuschem 10:2547–2559
1 3

Zr‑DBS with Sulfonic Group: A Green and Highly Efcient Catalyst for Alcoholysis of Furfuryl…
31. Jiang Z, Zhao X, Fu Y, Manthiram A (2012) Composite mem-
15. Démolis A, Essayem N, Rataboul F (2014) Synthesis and applica-
tions of alkyl levulinates. ACS Sustain Chem Eng 2:1338–1352
16. Lima TM, Lima CGS, Rathi AK et al (2016) Magnetic ZSM-5
zeolite: a selective catalyst for the valorization of furfuryl alcohol
to γ-valerolactone, alkyl levulinates or levulinic acid. Green Chem
18:5586–5593
branes based on sulfonated poly(ether ether ketone) and SDBS-
adsorbed graphene oxide for direct methanol fuel cells. J Mater
Chem 22:24862–24869
32. Dubey N, Pal A (2012) Micellar solubilization of octan-1-ol in
aqueous solutions of SDBS and TTAB. J Mol Liq 172:12–19
33. Ge X, Li H, Wu L et al (2017) Improved mechanical and barrier
properties of starch flm with reduced graphene oxide modifed
by SDBS. J Appl Polym Sci 134:1–8
17. Chappaz A, Lai J, De Oliveira VK et al (2018) Selective conver-
sion of concentrated feeds of furfuryl alcohol to alkyl levulinates
catalyzed by metal trifates. ACS Sustain Chem Eng 6:4405–4411
18. Peng L, Tao R, Wu Y (2016) Catalytic upgrading of biomass-
derived furfuryl alcohol to butyl levulinate biofuel over common
metal salts. Catalysts 6:143
34. Xu S, Yu J, Sun Y, Wu S (2015) Synthesis and characterization of
organic intercalated layered double hydroxides and their applica-
tion in bitumen modifcation. Mater Chem Phys 152:54–61
35. Zhou S, Dai F, Xiang Z et al (2019) Zirconium–lignosulfonate
polyphenolic polymer for highly efcient hydrogen transfer of
biomass-derived oxygenates under mild conditions. Appl Catal
B Environ 248:31–43
19. Wang G, Zhang Z, Song L (2014) Efcient and selective alcoho-
lysis of furfuryl alcohol to alkyl levulinates catalyzed by double
SO3H-functionalized ionic liquids. Green Chem 16:1436–1443
20. Chada RR, Koppadi KS, Enumula SS et al (2018) Continuous
synthesis of fuel additives alkyl levulinates via alcoholysis of
furfuryl alcohol over silica supported metal oxides. Catal Lett
148:1731–1738
36. Thorstenson TA, Urban MW (1993) Surface and interfacial FTIR
spectroscopic studies of latexes. IV. The efect of surfactant struc-
ture on the copolymer–surfactant interactions. J Appl Polym Sci
47:1381–1386
21. Gitis V, Chung SH, Raveendran Shiju N (2018) Conversion of fur-
furyl alcohol into butyl levulinate with graphite oxide and reduced
graphite oxide. FlatChem 10:39–44
37. Xue Z, Zhang J, Peng L et al (2014) Poly(ethylene glycol) stabi-
lized mesoporous metal-organic framework nanocrystals: efcient
and durable catalysts for the oxidation of benzyl alcohol. ChemP-
hysChem 15:85–89
22. Song D, An S, Lu B et al (2015) Arylsulfonic acid functional-
ized hollow mesoporous carbon spheres for efcient conversion
of levulinic acid or furfuryl alcohol to ethyl levulinate. Appl Catal
B Environ 179:445–457
38. Peng L, Zhang J, Li J et al (2012) Surfactant-directed assembly of
mesoporous metal–organic framework nanoplates in ionic liquids.
Chem Commun 48:8688–8690
23. Siva Sankar E, Saidulu Reddy K, Jyothi Y et al (2017) Alcoholysis
of furfuryl alcohol into n-butyl levulinate over SBA-16 Supported
heteropoly acid catalyst. Catal Lett 147:2807–2816
39. Côté AP, Shimizu GKH (2003) The supramolecular chemis-
try of the sulfonate group in extended solids. Coord Chem Rev
245:49–64
24. Wang Y, Zhao D, Triantafyllidis KS et al (2020) Microwave-
assisted catalytic upgrading of bio-based furfuryl alcohol to alkyl
levulinate over commercial non-metal activated carbon. Mol Catal
480:110630
40. Zhao Y, Zhang J, Han B et al (2011) Metal-organic framework
nanospheres with well-ordered mesopores synthesized in an ionic
liquid/CO2/surfactant system. Angew Chem Int Ed 50:636–639
41. Peng L, Gao X, Chen K (2015) Catalytic upgrading of renewable
furfuryl alcohol to alkyl levulinates using AlCl3 as a facile, ef-
cient, and reusable catalyst. Fuel 160:123–131
25. Sha Y, Xiao Z, Zhou H et al (2017) Direct use of humic acid mix-
tures to construct efcient Zr-containing catalysts for Meerwein-
Ponndorf-Verley reactions. Green Chem 19:4829–4837
26. Zhai P, Lv G, Cai Z et al (2019) Efcient production of ethyl
levulinate from furfuryl alcohol catalyzed by modifed zirconium
phosphate. ChemistrySelect 4:3940–3947
42. Liu H, Li Y, Jiang H et al (2012) Signifcant promoting efects
of Lewis acidity on Au–Pd systems in the selective oxidation of
aromatic hydrocarbons. Chem Commun 48:8431–8433
43. Guo Q, Yang F, Liu X et al (2020) Low-cost synthesis of nanoag-
gregate SAPO-34 and its application in the catalytic alcoholysis
of furfuryl alcohol. Chin J Catal 41:1772–1781
27. Tiwari MS, Gawade AB, Yadav GD (2017) Magnetically separa-
ble sulfated zirconia as highly active acidic catalysts for selective
synthesis of ethyl levulinate from furfuryl alcohol. Green Chem
19:963–976
44. Lu B, An S, Song D et al (2015) Design of organosulfonic acid
functionalized organosilica hollow nanospheres for efficient
conversion of furfural alcohol to ethyl levulinate. Green Chem
17:1767–1778
28. Song D, An S, Sun Y, Guo Y (2016) Efcient conversion of lev-
ulinic acid or furfuryl alcohol into alkyl levulinates catalyzed by
heteropoly acid and ZrO2 bifunctionalized organosilica nano-
tubes. J Catal 333:184–199
29. Neves P, Russo PA, Fernandes A et al (2014) Mesoporous zirco-
nia-based mixed oxides as versatile acid catalysts for producing
bio-additives from furfuryl alcohol and glycerol. Appl Catal A
Gen 487:148–157
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jurisdictional claims in published maps and institutional afliations.
30. Xie Y, Li F, Wang J et al (2017) Catalytic transfer hydrogenation
of ethyl levulinate to Γ-valerolactone over a novel porous Zirco-
nium trimetaphosphate. Mol Catal 442:107–114
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