Selective hydrodeoxygenation of biomass-derived furfural-acetone to prepare 1-octyl acetate

Article abstract of DOI:10.1039/c9gc01767d

A green and efficient catalytic system for the one-pot production of 1-octyl acetate from biomass-derived furfural-acetone (FFA) under mild conditions was developed by selective hydrodeoxygenation over Pd/C and Sc(OTf)₃ as a cocatalytic system in acetic acid. The effects of reaction conditions on product distribution have been systematically investigated. The highest 1-octyl acetate yield of 90% can be obtained under mild conditions (150 °C, 2 MPa H₂, 2 h). Tetrahydrofuran ring opening and ester bond selective cleavage were found to be the key steps. In these steps, due to its suitable Lewis acidity, Sc(OTf)₃ can not only promote ring-opening esterification but also selectively activate the secondary alcohol ester bond to achieve high selectivity for 1-octyl acetate. NMR and MS methods were utilized to investigate the reaction process. In addition, after 8 cycles of the Pd/C catalyst, the 1-octyl acetate yield gradually decreased from 90% to 80%. The decrease, according to XPS determination, in catalytic efficiency of the Pd/C catalyst was mainly due to the partial oxidation of metal Pd through air contact during post-treatment.

Full text of DOI:10.1039/c9gc01767d

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Page 1 of 15
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DOI: 10.1039/C9GC01767D
Selective Hydrodeoxygenation of Biomass-Derived Furfural-Acetone to
Prepare 1-Octyl Acetate
Xuyang Liu1,2, Yanbing Li1,2, Jin Deng1*, Yao Fu1*
1. Hefei National Laboratory for Physical Sciences at the Microscale, iChEM, CAS Key Laboratory of
Urban Pollutant Conversion, Anhui Province Key Laboratory of Biomass Clean Energy, Department
of Chemistry, University of Science and Technology of China, Hefei 230026, China.
* E-mail: dengjin@ustc.edu.cn, fuyao@ustc.edu.cn
2. Nano Science and Technology Institute University of Science and Technology of China Suzhou
215123 (P. R. China)
ABSTRACT: A green and efficient catalytic system for the one-pot production of 1-octyl acetate from
biomass-derived furfural-acetone (FFA) under mild conditions was developed by selective
hydrodeoxygenation over Pd/C and Sc(OTf)3 as a cocatalytic system in acetic acid. The effects of reaction
conditions on production distribution have been systematically investigated. The highest 1-octyl acetate
yield of 90% can be obtained under mild conditions (150 °C , 2 MPa H2, 2 h). The tetrahydrofuran ring
opening and the ester bond selective cleavage were found to be the key steps. In these steps, due to its
suitable Lewis acidity, Sc(OTf)3 can not only promote ring-opening esterification but also selectively
activate the secondary alcohol ester bond to achieve high selectivity for 1-octyl acetate. NMR and MS
methods were utilized to investigate the reaction process. In addition, after 8 times cycles of Pd/C
catalyst, the 1-octyl acetate yield gradually decreased from 90% to 80%. The decrease, according to XPS
determination, in catalytic efficiency of Pd/C catalyst was mainly due to the partial oxidation of metal
Pd through air contact during post-treatment.
KEYWORDS: Selective Hydrodeoxygenation, 1-Octyl Acetate, Biomass Conversion, Metal Triflate, Lewis
Acids
INTRODUCTION
In the past century, the air pollution and greenhouse effect have become very serious by the
extensive use of fossil resources.1 Biomass was considered as a promising alternative to petroleum
resources because of its renewable characteristics. Many efforts have been made worldwide to
convert biomass into fuels and value-added chemicals.2-4 Carbohydrates are the largest component
of biomass. Furfural, which is mainly produced from arabinose and xylose such as corn cob, is one
of the most important biomass platform chemicals in lignocellulose conversion.5-9 So far, many
strategies and methods have been proposed to convert furfural compounds into value-added
products, such as methylfuran10,11, long chain alkanes12,13, diols14,15 and acids16,17. Acetone can be
produced from renewable biomass by biological methods: acetone-butanol fermentation, which can
be considered as biomass chemicals.18 The further conversion of furfural and acetone to the
preparation of high value-added chemicals is of great significance.
1-Octanol is an important raw material in chemical industry, which plays a very influential role
in the production of detergents, surfactants and fragrances.19 It can also be used as a raw material
for the synthesis of 1-octene, an important co-monomer of polyethylene.20 There are two
petrochemical processes for the preparation of 1-octanol. One is the reaction of ethylene with
triethylaluminum. The other is oxo synthesis from n-heptene. Recently, a new non-petrochemical
route based on lignocellulose has been proposed in which furfural and acetone are condensed into
furfural-acetone (FFA, C8) and converted to 1-octanol. 21, 22

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DOI: 10.1039/C9GC01767D
Leitner et al. 21 firstly reported a process for 1-octanol preparation from biomass-derived FFA.
FFA was saturated to 4-(2-tetrahydrofuryl)-2-butanol (THFA) by Ru/C at 120°C with 120 bar
hydrogen pressure firstly. Then, with the acidic additive [BSO3BIM][NTf2], THFA was converted
into an equimolar mixture of 1-octanol and 1-octyl ether over Ru/C via deoxygenation and ring
opening in [EMIM]-[NTf2] at 150°C and 120 bar hydrogen pressure without selectivity. In addition,
Wang et al. 22 reported an energy-efficient catalytic system in which 1-octyl alcohol was prepared
from FFA in aqueous phase with a yield of 63%. They used hydrophilic Pd/NbOPO4 and TfOH as
the additive to catalyze the conversion. Hydrophobic 1-octanol phase-separated from the polar
catalyst surface to avoiding total deoxygenation to octane (Scheme1). However, 1-octanol yield in
previous studies were still comparatively low, while the reaction time was too long. Therefore, the
preparation of 1-octanol and its derivatives in high efficiency, high selectivity and high yield from
biomass-based FFA still poses a significant challenge.
Scheme1. Synthesis of 1-octanol/1-octyl acetate from biomass-derived FFA
Our previous work 23, 24 found that in the presence of hydrogenation catalyst (Pd/C), the metal
triflate can promote not only hydrodeoxygenation reaction under mild conditions, but also the ring
contraction of biomass-based macrolide compounds into stable five-membered lactones. At the
same time, metal triflate can convert biomass derivatives into a carboxylic acid by ring opening.
25,26
27
We then reported that carboxylic acids or α,ω-dicarboxylic acids can be obtained from
cellulose-derived platform chemicals in the presence of W(OTf)6 indicating that a metal triflate can
give high selectivity to carboxylic acid while removing other oxygen-containing groups. The ester
28
group could be selectively retained through regulating the Lewis acidity of the metal triflate.
Based on our previous work, we hypothesized whether the Lewis acidity of metal triflate can be
adjusted to promote both the FFA hydrogenation to a saturated ring and the esterification ring
opening as well as the hydrogenolysis of the secondary alcohol ester, thereby achieving high
selectivity to 1-octyl acetate in high yields under mild conditions.
Herein, we describe the efficient catalytic synthesis of 1-octyl acetate from the aldol
condensation adduct of furfural and acetone, using Sc(OTf)3 and Pd/C as the catalysts and acetic
acid as the solvent. Since Sc(OTf)3 has a suitable Lewis acidity, it can selectively activate the
secondary alcohol ester and avoid the removal of primary alcohol ester, to achieve a high selectivity
towards 1-octyl acetate. Meanwhile, over-hydrogenation of 1-octyl acetate can be significantly
restrained. The highest yield of 1-octyl acetate (90%) was obtained from one-pot conversion of
biomass-derived FFA over Sc(OTf)3 and Pd/C.

Page 3 of 15
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DOI: 10.1039/C9GC01767D
EXPERIMENT
Materials and reagents
All chemicals used in the experiments were commercially available. Hf(OTf)4, Pd/C (10%) were
purchase from Alfa Aesar (China) Chemicals Co., Ltd. La(OTf)3, Bi(OTf)3, Sc(OTf)3, Al(OTf)3 Ni(OTf)2,
Zn(OTf)2,Cu(OTf)2 were purchased from Adamas Reagent Co., Ltd. Phenylbenzene, furfural, acetic acid,
and dichloromethane were purchased from Sinopharm Chemical Reagent Co., Ltd. Pure water was
bought from Hangzhou Wahaha. The spectroscopic data of intermediates and products are given in the
Supporting Information.
Unless stated otherwise, reactions were carried out in an autoclave from Anhui Kemi Machinery
Technology Co., Ltd. Usually, the initial temperature was 30oC, before heating to the required reaction
temperature in 30 min by using a temperature controller. The reaction was then subjected to constant
heating for a defined period of time.
The conversion of FFA was carried out in a 25 mL Parr autoclave equipped with magnetic stirring,
temperature probe, and heating controller. Substrate (0.75 mmol), Pd/C (2 mol%), metal triflates (4
mol%), and acetic acid (5 mL) were added to the autoclave. The screws were tightened and the gas was
replaced with hydrogen gas four times. The autoclave was then filled to a defined hydrogen pressure at
room temperature and heating to the desired temperature under stirring in 500 rpm/min. After a defined
period of reaction at constant heating, the reaction mixture was allowed to cool to room temperature, the
pressure was released, and the reaction mixture was transferred out of the reactor with dichloromethane
(20 mL) A known amount of phenylbenzene was added to the solution as an internal standard and the
solution was analyzed by gas chromatography (30 m*0.32 mm* 0.25 mm, Shimadzu, GC-2014C
equipped with a DM-Wax capillary column).
RESULTS AND DISCUSSION
Our previous work has confirmed that metal triflate played an important role in determining
the product distribution of the reaction system. Thus, in the reaction with FFA as the substrate and
acetic acid as the solvent, various metal triflates were first screened to investigate the effect of
different catalysts on product distribution (Table 1).
Table 1. The screening of metal triflate in the hydrodeoxygenation of FFA
Yield/%
Entry
Metal triflate
Conversion/%
TA
8
0
0
0
0
0
0
0
0
0
OTA
10
7
1
40
7
15
20
10
40
12
OA
68
70
90
29
67
45
64
71
31
60
Octane Others
1
2
3
4
5
6
7
8
9
La(OTf)3
Hf(OTf)4
Sc(OTf)3
Cu(OTf)2
Fe(OTf)3
Al(OTf)3
Zr(OTf)4
Zn(OTf)2
Bi(OTf)3
Er(OTf)3
100
100
100
100
100
100
100
100
100
100
12
18
8
2
5
1
8
23
14
14
2
3
24
10
12
26
14
16
5
10
18
Reaction conditions: FFA(0.75mmol), H2 (2MPa), 120min, 10% Pd/C (2 mol %), acetic acid (5 mL) and 150oC. TA:
4-(tetrahydrofuran-2-yl)butan-2-yl acetate; OA: 1-octyl acetate; OTA: octane-1,4,7-triyl triacetate; Others including
products that cannot be detected.

Green Chemistry
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The experimental results showed that FFA has been completely converted with all thDeOaI:d1o0p.1t0e3Vd9ie/Cw9AGrtCicl0e1O7n6l7inDe
metal triflates. In addition to the selective hydrodeoxygenolysis target compound OA, hydrogenated
saturated esterification product TA, esterified ring-opening product OTA and over
hydrodeoxygenolysis product octane can be detected in the products. Gordon et al. 29 found that the
hydrogenated saturated tetrahydrofuran ring is more difficult to open than the furan ring. However,
the furan ring is easily saturated to a tetrahydrofuran ring with hydrogen with the presence of Pd/C.
23
30
28
Fortunately, Miles et al.
and us
have found that the metal triflate can catalyze the
tetrahydrofuran ring opening via esterification. The intermediate OTA, obtained by the esterification
ring opening reaction, contains secondary alcohol ester and primary alcohol ester in its molecular
structure. Compared to the primary alcohol esters, secondary alcohol esters are more susceptible to
activation by Lewis acids due to the substituent effect.25, 31 Additionally, the Lewis acidity of the
metal triflate is positively correlated with the charge density of metal ion. 31 Therefore, for metal
triflates which have weaker Lewis acidity such as Cu(OTf)2 (charge density = 2.74) or Bi(OTf)3
(charge density = 2.91), we mainly observed the opening of tetrahydrofuran without breaking the
ester C-O bond compound OTA. Whereas, for metal triflates with stronger Lewis acidity such as
Hf(OTf)4 (charge density = 5.63) or Al(OTf)3 (charge density = 5.61), not only the secondary
alcohol ester C-O bond was cleaved via hydrogenolysis but also the primary alcohol ester C-O bond
was cleaved. Thereby the over-hydrogenated product n-octane (OT) was obtained. For Sc(OTf)3
(charge density = 4.03) with suitable Lewis acidity, the target compound OA can be obtained with
high selectivity in a yield of 90% within 2h. We speculate that Sc(OTf)3 can effectively catalyze
ring opening and activate the secondary alcohol ester group C-O bond while retaining the primary
alcohol ester.
Therefore, we used 1-octyl acetate and 2-octyl acetate as models, through Pd/C catalytic
hydrogenolysis experiments, to investigate the effect on conversion rate of primary and secondary
alcohol esters with Al(OTf)3, Sc(OTf)3 and Bi(OTf)3 respectively. Regardless of the metal triflate
catalyst used, the conversion rate of 2-octyl acetate was higher than 1-octyl acetate. At the same
time, the conversion rate of ester was positively correlated with the charge density of metal triflate.
Al(OTf)3 has the highest reactivity with octyl acetate (whether 1-octyl acetate or 2-octyl acetate).
For Bi(OTf)3, which has the weakest acidity of Lewis, the conversion rate was the slowest.
According to the largest ratio of two conversion rates, Sc(OTf)3 that has a moderate lewis acidity,
showed the best selectivity (SI-II).

Page 5 of 15
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Figure 1. Effect of reaction temperature. Reaction conditions: FFA(0.75mmol), H2 (2MPa), 120min,
10% Pd/C (2 mol %), Sc(OTf)3 (4 mol%), and acetic acid (5 mL).
Considering the importance of reaction temperature for ring opening, we investigated the effect
of reaction temperature on the ring opening of tetrahydrofuran ring. The yield of OA was 8% at
100°C . The main product was TA, which was produced by hydrogenation of furan ring and
esterification of its side chain. Only a small amount of OTA was formed. These results indicated
that the catalyst had a poor ring opening effect on tetrahydrofuran ring at a low temperature. As the
reaction temperature increased to 120°C , the yield of OA increased, mainly due to the promoted
ring opening reaction of TA at an elevated temperature. At this point, a small amount of octane was
formed, accompanied by a large amount of the unopened intermediate. With the increase of reaction
temperature to 135°C , a significant increase of the intermediates OTA was detected with TA being
eliminated. Further increasing the reaction temperature, the yield of OA increased first and then
decreased, with the highest yield of OA being obtained at 150°C . The yield of octane is increases
with the increasing temperature. At 180°C , we found that the carbon yield was slightly reduced.
This may be due to the high reaction temperature resulting in polymerization of the raw materials
as well as in depolymerize (SI-I). In this reaction, we speculated that TA, the hydrogenated saturated
esterification product of FFA, was ring opened to obtain OTA. There are two different types of ester
bonds on OTA, one is primary ester and the other is secondary alcohol ester. As the cleavage activity
trend is in the following descending order: tertiary>secondary>primary, the secondary alcohol
acetate was selectively cleaved in the OTA intermediates to give OA. The yield of OA reduced from
90% to 48%, with a significant increase of octane when the reaction temperature was raised to 180°C .
These indicated that an excessively high temperature was detrimental to the formation of OA,
resulting in total deoxygenation.

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Figure 2. Effect of Substrate concentration. Reaction conditions: H2 (2 MPa), 120 min, 10% Pd/C
(2 mol %), Sc(OTf)3 (4 mol%) acetic acid (5mL), and 150°C .
Since the metal triflate and Pd/C system has a high hydrogenation activity on the substrate, it
was completely converted at all concentrations. When the substrate concentration was 0.36 mol/L,
the raw material was not completely converted to OA due to the low catalyst concentration. The
yield of OA was 83% (Fig. 2), while the yield of octane and OTA were 6% and 8% respectively. As
the substrate concentration was raised to 0.72 mol/L, the yield of OA increased to 90% and that of
OTA decreased slightly from 8% to 0. This indicated that raw materials could be converted with
high selectivity under the appropriate substrate concentration. Further increasing the substrate
concentration to 1.08 mol/Land 1.44 mol/L, we found that the yield of target product OAwas greatly
reduced (from 90% to 51% and 43% respectively) while that of octane was significantly increased
(from 8% to 17% and 24% respectively). Thus very high substrate concentrations inclined to induce
deep hydrodeoxygenation, which was detrimental to selective hydrogenolysis of secondary alcohol
esters. Meanwhile, we found that there were many undetectable products at 1.08 mol/L and 1.44
mol/L of substrate concentrations, presumably because the raw materials were converted to polymer
at higher concentrations which could not be detected. We therefore determine that 0.72mol/L was
the optimal substrate concentration. A lower concentration of FFA may lead to the incomplete
transformation of FFA to OA, while higher concentrations resulted in a significant increase of over-
hydrogenated products.

Page 7 of 15
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Figure 3. Effect of hydrogenation catalyst. Reaction conditions: FFA (0.75 mmol), H2 (2MPa), 120
min, Sc(OTf)3 (4 mol%), acetic acid (5 mL), and 150°C .
A series of experiments were carried out to explore the effect of different catalysts on product
distribution. It can be seen from Fig. 3 that Pd/C had the best catalytic performance. This may be
because the metal triflate activated the ester bond to effect β-H elimination to form a C=C bond.25
Pd/C or Pt/C catalyst, which have high C=C bond hydrogenation activity. Pt/C also has a strong
ability to break C-O bonds leading to a lot of alkanes being obtained. However, Ru/C and Rh/C
showed poor hydrogenation activity in this system, causing a lower yield of target product. For Ru/C
catalyst, due to its large metal d-band, the electron repulsion between C=C bond and metal surface
32
is enhanced, which is not conducive to the adsorption of C=C bond, thus resulting in a lower
catalytic activity of Ru/C. At the same time, a series of experiments were carried out to explore the
effect of catalysts dosage on product distribution. We have found that when the amount of
hydrogenation catalyst Pd/C used was low, there were more incompletely hydrogenolysis
intermediates in the reaction product, such as TA and OTA. However, when the amount of the
hydrogenation catalyst Pd/C used was high, a large amount of deep hydrogenolysis product OT was
produced. Therefore, the optimum amount of the Pd/C catalyst is 2 mol% (15 mg). (SI-III)

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Figure 4. Effect of Hydrogen pressure. Reaction conditions: FFA (0.75 mmol), 120 min, 10% Pd/C
(2 mol %), Sc(OTf)3 (4 mol%), acetic acid (5 mL), and 150°C .
The raw material can be fully converted at low hydrogen pressure (0.5 MPa H2), but the
selectivity to OA was very low (26%). There was some OTA (22%) generated, but the carbon yield
was only about 50%. We determined that the raw materials may polymerize to form polymers at
lower hydrogen pressure which cannot be detected by GC. When the hydrogen pressure was
increased to 2 MPa, the yield of OA greatly increased to 90%, whereas the yield of OTA decreased
sharply from 22% to 1%. Such results indicated that the increased hydrogen pressure was beneficial
for the cleavage of ester bonds. As the hydrogen pressure was further increased to 3 MPa and 4 MPa,
the yield of OA decreased slightly with a slight increase of octane. There exists an indirect
relationship between pressure and catalyst selectivity. That is, an increase in pressure negatively
affects catalyst selectivity, vice versa. The C-O bond of the terminal ester group was broken when
the hydrogen pressure was high. In summary, the optimum hydrogen pressure was 2 MPa. The
highest yield of OA (90%) was obtained at 150 °C under 2 MPa H2 for 2 h.
The initial temperature of the reaction is 20°C and the first 30 minutes of reaction is for pre-
heating. As can be seen from Fig. 5, the raw material FFA began to be converted into various
intermediates in the course of the heating process. At the initial stage of reaction, the main that
occurred was hydrogenation of FFA to produce 4-(tetrahydrofuran-2-yl)butan-2-one (TB), and 70%
of TA was detected when the reaction was carried out until 20 minutes. As time increased, TA
content decreased continuously to 0 at 50 min. When the reaction time was 40 min, TA and OTA
began to substantially convert into target product massively. The yields of OA and octane were 60%
and 3% respectively at this time.

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Figure 5. Effect of reaction time. Reaction conditions: FFA (0.75mmol), 10% Pd/C (2 mol%),
Sc(OTf)3 (4 mol%), acetic acid (5mL), 150 °C , and 2 MPa H2.
Such results indicated that Sc(OTf)3 was an excellent tetrahydrofuran ring-opening catalyst on
a short time scale. When the reaction time is short, a large amount of intermediate products are non-
convertible. The yield of OA increased, accompanied by a continuous decrease of intermediates
along with the extension of reaction time. The highest yield of OA reached to 90% at 150 min with
8% octane yield. Subsequently, the yield of the by-product increased with the reaction time progress.

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(a)
(b)
1
1
Figure 6. (a) H NMR spectra of intermediates and products. (b) H-NMR spectra of reaction
mixtures at different reaction times.
In order to monitor the progress of reaction, 1H-NMR was used to analyze the reaction mixtures
at different reaction times. The results were shown in Figure 6. Our initial reaction temperature was
30°C , and it was raised to 150°C in 30 minutes, and then the temperature was maintained at 150°C
for a period of time until the reaction was completed.

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1
First, we compared the H-NMR peaks of the reaction mixtures at different reaction times.
DOI: 10.1039/C9GC01767D
Peaks at ~6.72 ppm, ~3.75 ppm, ~4.89 ppm, and ~0.80 ppm were found to correspond to the raw
materials, TB, OTA, OA, respectively. It is found that the unsaturated C=C bond in the FFAsaturated
quickly when the temperature was raised. At the same time, the peak at 3.75 ppm proved that the
tetrahydrofuran ring in intermediates was not opened. Both OTA and OA formed after heating for
30 minutes. A gradual decrease in the peak at 3.75 ppm indicated that the tetrahydrofuran ring in
the intermediates was subjected to a ring opening reaction. After heating for 90 min, the peak at
3.75 ppm disappeared, demonstrating that all of the intermediates were ring-opened at this point.
When the reaction was carried out for 150 minutes, the 1H-NMR spectrum of reaction mixture was
substantially the same as the one of 1-octyl acetate. This verified that the conversion of raw materials
was completed.
From this we can speculate on the mechanism of the reaction (Scheme 2):
Scheme 2. Proposed reaction mechanism.
In order to verify the reaction mechanism mentioned in Scheme 2, we did a series of
experiments (detail experiment procedures see SI-III). The C=C bond in FFA were first saturated in
the presence of Pd/C and H2 to form TB. Then, hydrogenated intermediate TB was used as substrate
to carry out the reaction. The results indicated that TB can also be converted to OA. When the
reaction time was less than 30 min, an intermediate TA which tetrahydrofuran ring was not ring-
opened was mainly formed. When the reaction time was 90 min, the highest OA yield (88%) was
obtained. As the time increases further, the yield of by-product OT increased, which was detrimental
to the reaction. In addition, the reaction of intermediate TA as the substrate was also carried out. We
found that Sc(OTf)3 catalyzes the ring opening of tetrahydrofuran ring at high temperature (150°C)
without hydrogen, and TA can be converted into OTA. Last, the reaction of intermediate OTA as the
substrate was also carried out under standard reaction conditions, and we found that the main
product was OA. According to the above conclusion, metal triflate can promote hydrogenolysis of
secondary alcohol esters while retaining primary alcohol esters, thereby achieving selective
hydrodeoxygenation (Sel-DHO). Therefore, only OA was obtained as a product and no other ester
was detected. The catalytic system can further convert OA to OT under conditions of increasing the
reaction temperature or the hydrogen pressure and prolonging the reaction time.

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Figure 7. Catalyst recycling. Reaction conditions: FFA (0.75mmol), 120min, 10% Pd/C (2 mol %),
Sc(OTf)3 (4 mol%), acetic acid (5mL), 150°C , and 2 MPa H2.
Figure 7 shows the results of the catalyst recycle experiment. The experiments were carried
out in the following steps: biphenyl was added as an internal standard for quantitative product
analysis. The reaction solution was filtered to collect Pd/C, which was then dried and used for the
next cycle. Results showed that the product distribution remained unchanged after six cycles and
exhibited stability. After six cycles, the yield of OA decreased and the OTA increased, which may
be due to the formation of Pd particle clusters resulting in a decrease in catalytic activity. To confirm
this possibility, XRD and TEM tests were performed. According to the XRD, the peak signal
intensity of the used Pd/C was higher than that of the fresh Pd/C, indicating that Pd/C aggregated
during the reaction. The TEM also showed that Pd particles were evenly distributed before the
reaction and partially agglomerated after use. These characterizations indicate that decrease in
catalyst activity is related to the form of clusters of Pd/C during the reaction. Meanwhile, XPS
results showed a change in the ratio of Pd0 and Pd2+ substances in the Pd/C catalyst. An increase in
the proportion of Pd2+ species and loss of catalyst recovery may result in a decrease in yield (SI-IV).
CONCLUSION
In summary, by using a highly selective hydrodeoxygenation complex catalytic system to
selectively remove secondary ester groups, we have demonstrated a green catalytic system for the
one-pot production of 1-octyl acetate from biomass-derived FFA. Up to 90% 1-octyl acetate yield
can be obtained under optimum conditions of 150°C and 2 MPa H2 with Sc(OTf)3 and Pd/C. The
highly efficient catalytic system achieves a selective hydrodeoxygenation reaction of biomass-based
oxygenates. This reaction provides a new strategy and a concise process for the highly selective
production of medium and long chain primary alcohol esters from biomass-derived molecules.

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ASSOCIATED CONTENT
Supporting Information
Full experimental details, experimental procedures, products characterization data including 1H and
13C NMR spectra and detailed mechanistic data.
AUTHOR INFORMATION
Corresponding Author
*E-Mail: dengjin@ustc.edu.cn;
*E-Mail: fuyao@ustc.edu.cn.
ORCID
Jin Deng: 0000-0003-0272-1031
Yao Fu: 0000-0003-2282-4839
Notes
The authors declare no competing financial interests
ACKNOWLEDGMENT
This work was supported by National Key R&D Program of China (2018YFB1501604, 2018YFB1501502),
National Natural Science Foundation of China (21875239, 21572212, 51821006), Strategic Priority Research
Program of CAS (XDA21060101), the Fundamental Research Funds for the Central Universities (WK3530000004)
and Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01N092).
The authors thank the Hefei Leaf Biotech Co., Ltd. and Anhui Kemi Machinery Technology Co., Ltd. for free
samples and equipment that benefited our ability to conduct this study.
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DOI: 10.1039/C9GC01767D
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