Versatile catalysis of iron: Tunable and selective transformation of biomass-derived furfural in aliphatic alcohol

Article abstract of DOI:10.1039/c8gc00852c

An iron-catalyzed efficient valorization of biomass-derived furfural (FUR) in aliphatic alcohols is developed in which product selectivity can be simply regulated by varying the gas atmosphere. In the presence of molecular oxygen, there is oxidative condensation of FUR with ethanol, and the obtained product is furan-2-acrolein in a "FUR-ethanol-O₂" system. Under suitable conditions, the conversion of FUR and selectivity of furan-2-acrolein are 84.2% and 82.7%, respectively. In the presence of H₂, the selective hydrogenation of FUR is achieved, and the main product is furfuryl alcohol in a "FUR-ethanol-H₂" system. Under optimal conditions, a 99.9% conversion of FUR and 93.6% selectivity of furfuryl alcohol are attained. This provides an economic, green and sustainable method for the utilization of biomass-based platform compounds in the chemical industry.

Full text of DOI:10.1039/c8gc00852c

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Versatile catalysis of Iron: tunable and selective transformation
of biomass-derived furfural in aliphatic alcohol
Zhenya Zhang a, Xinli Tong,*a Haigang Zhang a and Yongdan Li b
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
Abstract: Iron-catalyzed efficient valorization of biomass-derived furfural (FUR) in aliphatic alcohols is developed in which
the product selectivity can be simply regulated by varying the gas atmosphere. In the presence of molecular oxygen, the
oxidative condensation of FUR with ethanol occurs and the obtained product is furan-2-acrolein in ^FUR-ethanol-O2_
system. Under suitable conditions, the conversion of FUR and selectivity of furan-2-acroleinin are 84.2% and 82.7%,
respectively. In the presence of H2, the selective hydrogenation of FUR is achieved and the main product is furfuryl alcohol
in FUR-ethanol-H2_ system. Under optimal conditions, a 99.9% conversion of FUR and 93.6% selectivity of furfuryl alcohol
is attained. It provides an economic, green and sustainable method for utilization of biomass-based platform compound in
chemical industry.
www.rsc.org/
transport fuels.17 In the previous study, the usual catalysts for
oxidative condensation is concentrated on the Au, Pt and Co
supported catalysts.18-21 For example, a 94.1% conversion of
FUR with 75.0% selectivity of 2-furan-acrolein was attained
Introduction
In the near few decades, the increasing energy demand and
excessive use of fossil energy make people to face serious
fossil energy crisis and environment pollution. Therefore,
seeking a new type of energy to alternatively and eventually
using Au/Al2O3 catalyst in FUR-ethanol-O2 system; 18 moreover,
a 93.9% conversion of FUR and 67.9% selectivity to furan-2-
acrolein were obtained with Pt/FH as catalyst.19 Very recently,
we found that the active species from 2D Co-based metal-
organic framework can mediate the oxidative condensation of
FUR with n-propanol in the presence of molecular oxygen
where 84.9% conversion and 99.9% selectivity of 3-(furan-2-yl-
)-2-methylacryl aldehyde is obtained under mild conditions.21
Herein, it needs to mention that the oxidative esterification of
FUR with aliphatic alcohol is the competitive reaction in the
^FUR-alcohol-O2_ system, in which the metal Au and Ce were
often used as catalysts. 17, 22-24
replace the traditional energy and resource is
a vital
challenging task.1-4 Biorefinery has been considered as a
promising approach to solve the fossil energy crisis and the
environment pollution radically.5-7 During the utilization of the
abundant renewable biomass source, the efficient
transformation of bio-based platform compound to fuels and
chemicals has become more and more important.8-9 Because
the furfural (FUR) can be easily produced from cheap corncob,
straw and wastes, its valorization been paid numerous
attentions in the chemical field.10-14
On the other hand, the hydrogenation of FUR to generate
furfuryl alcohol (FOL) is a very attractive catalytic synthesis
method in the chemical industry. To sum up, the actual FOL
production utilizes 65% of the overall FUR produced.25 FOL is
often employed in the production of resin as high-quality
mould for the metal casting in the foundry industry. Also, FOL
is used as a reactive solvent for phenolic resins in the
refractory industry, as a viscosity reducer for epoxy resins in
the manufacture of polyurethane foams and polyester;26 In
addition, ethyl furfuryl ether, levulinic acid (LA)U v-
valerolactone is also often produced with furfuryl alcohol as
Generally, utilization of FUR as the starting material could
synthesize
a variety of chemicals including numerous
commercial products,15 in which FUR can be efficiently
converted by hydrogenation, oxidation, reductive amination,
decarbonylation, nitration, condensations, etc..16 In particular,
the oxidative condensation of FUR with aliphatic alcohol is a
feasible approach to impel two carbon molecules together and
produce longer hydrocarbon chains and low volatile liquid
feedstock.25, 26 In previous reports, the used catalysts in the
a.Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion,
School of Chemistry and Chemical Engineering, Tianjin University of Technology,
Tianjin 300384, P. R. China. Tel: (+86)-22-60214259; E-mail: tongxinli@tju.edu.cn;
tongxli@sohu.com.
27
liquid phase hydrogenation of FUR have Ni34.1Fe36.0B29.9
28
,
Ni74.5P12.1B13.4
,
copper chromite,29 Cu3/2PMo12O40/Raney Ni,30
CuNi-MgAl mixed oxides31 Co-B amorphous alloy30 and Ru (II)
bis(diimine) complexes.32 For present industrial production, it
has been proposed that the liquid-phase hydrogenation of FUR
can be carried out by mixing copper chromite with FUR to form
b.School of Chemical Engineering, Tianjin University, Tianjin 300072, P. R. China.
• C}}šv}šꢀ• Œꢀoꢁš]vP š} šZꢀ š]šoꢀ ꢁvꢂl}Œ ꢁµšZ}Œ• •Z}µoꢂ ꢁ‰‰ꢀꢁŒ ZꢀŒꢀX
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
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(furan-2-ylmethylene) hexanal was attained when n-hexanol was
employed (entry 5). Although the product yield is related to the
molecular structure of aliphatic alcohol, it shows a promising
process for regulation of carbon chain in the utilization of bio-based
furanic platform compound.
Scheme 1. The reaction equation of FUR with ethanol-O2
Table 1. The oxidative condensation reaction of FUR and ethanol
using different catalysts [a]
.
Table 2. Oxidative condensation reaction of FUR in different
alcohols with Fe@C catalyst [a]
Selectivity(%)[b]
Conv.
Entry
catalytic system
Fe@C+K2CO3
[b]
(%)
2
3
1.2
0
4
2.9
1.4
0
Others
13.2
0
Conv.
Selectivity of product
(%)[b]
Entry Aliphatic Alcohols
1
2
84.2
18.8
27.9
15.6
57.3
46.9
61.1
62.8
92.4
93.1
96.8
94.9
82.7
98.4
>99
>99
[b]
(%)
Fe(III)EDTA+K2CO3
Fe2O3@C+K2CO3
Fe podwer+K2CO3
Fe/C + K2CO3
Ni@C+ K2CO3
Co@C+K2CO3
Pd/C+ K2CO3
1
n-propanol
86.7
96.2
3
0
0
2
3
4
5
i-propanol
n-butanol
n-pentanol
n-hexanol
50.7
55.6
34.9
26.8
78.1
53.3
47.9
36.4
4
0
0
0
5
63.3 32.4 4.3
40.4 36.8 22.8
57.8 38.1 4.1
0
6
0
7
0
8
86.2
74.1
79.3
77.9
71.2
0
0
0
0
13.8
25.9
12.3
8.3
21.9
[a] Reaction Conditions: FUR 0.20g, catalyst 50 mg, K2CO3 50 mg, 15 mL aliphatic alcohol, 140
ºCÈ0.3 Mpa of O2, for 4 h.
9
Pt/C+K2CO3
10[c]
11[d]
12[e]
Fe@C+K2CO3
Fe@C+K2CO3
Fe@C+K2CO3
2.1
6.4
[b] The experimental results are obtained by GC with the internal standard method.
1.7 12.1
In order to further reveal the influence of base additives in the
reaction, several additives including Cs2CO3, Na2CO3, NaHCO3, KOH,
KOAc, K3PO4, NaOH, NaOAc, NaOMe, NaOEt, Na2SiO3, CaCO3 and
NaHSO4 were chosen and used in oxidative condensation of FUR
with ethanol in the presence of oxygen. As shown in the Figure 5,
when K2CO3 is used as the additive, a 76% yield of 2 is achieved.
Moreover, a 60% yield of 2 is attained when Cs2CO3 is used as the
additive. However, when the additive is switched as Na2CO3 and
NaHCO3, the yield of 2 drops to 13% and 3%. Moreover, it was
found that when the basicity of additive is decreased, the reaction
pathway favors the acetalization of FUR to form compound 3,
instead of the oxidative condensation reaction for producing
compound 2. Furthermore, when KOH, KOAc or K3PO4 are added, a
48%, 2% or 43% yield of 2 are obtained. In the case of NaOH, 44%
yield of 2 are obtained. Similarly, 17%, 28% or 17% yield of
compound 2 is attained using NaOAc, NaOMe or NaOEt is used as
the additive. In addition, Na2SiO3 and CaCO3 are also employed as
the additives for the oxidative condensation of FUR with ethanol, in
which a 24% or 23% yield of 2 is obtained, respectively. In contrast,
when NaHSO4 is used as the additive, the selectivity of 2 decreases
to near to zero where the production of compound 3 becomes
dominant. Considering catalytic effectiveness and the cost, K2CO3 is
the most efficient additive for the oxidative condensation.
4.6
2.3
-
13
14
15
Fe@C
K2CO3
-
16.2
27.6
3.2
-
56.5
-
-
-
>99
-
43.5
-
-
-
>99
16[f]
Fe@C+K2CO3
68.5
51.3
48.7
-
[a] Reaction conditions: FUR 0.20g, catalyst 50 mg, K2CO3 50 mg, in 15 mL aliphatic alcohol, 140
ºC, under 0.3 Mpa of O2, for 4 h.
[b] The experimental results are obtained by GC with the internal standard methods.
[c] The reaction was performed at 160 ºC;
[d] The reaction was carried out at 180 °C;
[e] The reaction was prolonged to 24 h.
[f] The reaction was performed under N2 atmosphere.
The transformation of FUR in different alcohols is also investigated
with Fe@C catalyst, and the results are shown in Table 2. In the
oxidative condensation of FUR with n-propanol, 86.7% conversion
and 96.2% selectivity of 3-(furan-2-yl-)-2-methylacryl aldehyde is
obtained (entry 1). When i-propanol or butanol was used, a 50.7%
and 55.6% conversion of FUR with 78.1% or 53.3% selectivity of
oxidative condensation product was attained (entries 2 and 3),
which shows that the position of hydroxyl group and chain length of
molecule have some negative effect on this catalytic system. In case
of n-pentanol, a 34.9% conversion of FUR and 47.9% selectivity of 2-
(furan-2-ylmethylene)pentanal was obtained in reaction (entry 4).
Similarly, a 26.8% conversion of FUR and 36.4% selectivity of 2-
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Table 3. Effects of additives in the oxidation condensation of FUR [a]
.
gradually increased and the yield of 2 reached highest at 450 °C.
When the calcination temperature is elevated to 550 ºC, a 67%
conversion of FUR with 82% of selectivity of 2 is attained. In
addition, the catalytic activity drops dramatically at 650 ºC in which
only 10.5% yield of 2 is obtained. Thus, the optimal calcination
temperature is 450 ºC for the thermal reduction of catalyst.
The effect of reaction temperature in the ^FUR-ethnaol-O2_
system was also studied, and the obtained results are shown in
Figure 6. It can be seen that the conversion of FUR is gradually
increased and almost keeps unchanged at 140°C; meanwhile, the
selectivity to 2 is decreased along with the increase of temperature
from 110 to 140°C, after which it starts to level off. Compared to
that of 2, the selectivity of 4 shows a contrary trend. It proves that
there exists a mutual relationship between the compound 2 and 4
during the whole reaction.
Selectivity(%)[b]
[b]
Entry Additive Conv. (%)
2
3
4
Others
1
2
K2CO3
Cs2CO3
Na2CO3
NaHCO3
KOH
84.2
72.9
17.5
8.8
82.7 1.2
81.8 3.5
2.9
3.3
13.2
11.4
3
76.8 19.4 3.8
31.9 65.2 2.9
56.3 1.1 27.9
42.8 5.4 51.8
-
4
-
5
85.1
4.4
14.7
6
KOAc
0
7
K3PO4
NaOH
49.2
91.8
18.4
39.2
19.2
48.6
33.2
11.3
88.2
47.9
93.8
0
0
0
10.9
46.7
6.2
0.9
8
5.4
9
NaOAc
NaOMe
NaOEt
Na2SiO3
CaCO3
NaHSO4
-
-
-
-
-
-
10
11
12
13
14
71.6 3.6 24.8
87.7 5.4 6.9
49.9 36.7 13.4
70.1 12.4 17.5
Conversion of FUR
Selectivity of 2
100
Selectivity of 4
Selectivity of others
-
99
-
[a]
Reaction conditions: 0.20g FUR, 50 mg catalyst, 50 mg additive, 15 mL ethanol, 140 ºC,
80
60
40
20
0
under 0.3 Mpa of O2, for 4 h.
[b] The experimental results are obtained by GC with the internal standard methods.
100
Covnersion of FUR
Selectivity of 2
Yield of 2
80
60
40
20
0
100
110
120
130
140
150
160
Reaction temperature / èC
Figure 6. Effect of reaction temperature in the ^FUR-ethanol-O2_
system (Reaction conditions: 0.20 g FUR, 50 mg catalyst, 50 mg
K2CO3, 15 mL ethanol, under 0.3 MPa of O2, t=4 h)
350
400
450
500
550
600
650
The effect of time in the ^FUR-ethnaol-O2 system_ is presented in
Figure 7. The conversion of FUR increases as the reaction proceeds
from 0.5 h to 4 h, and then keeps unchanged almost. Meanwhile,
the selectivity of 2 increases gradually in the first 2 h then declines
when reaction time is prolonged. As a result, the highest yield of 2
reaches 76% after 4 h using the Fe@C and K2CO3 as the catalyst.
Thus, the optimal reaction time should be 4 h in the oxidative
condensation process.
Calcination temperature / èC
Figure 5. Effect of calcination temperature in the oxidative
condensation of FUR with etahnol (Reaction conditions: 0.20 g FUR,
50 mg catalyst, 50 mg K2CO3, 15 mL ethanol, under 0.3 MPa of O2,
T=140 ºC, t=4 h)
The effect of calcination temperature of catalyst was explored
(Figure 5). The calcination and reduction temperature ranged from
350 ºC to 650 °C for the catalyst preparation. The activity of the
catalyst after being treated at 350 ºC is still relatively low and the
selectivity of 2 is also not satisfactory. However, along with the
increase of the calcination temperature, the activity of the catalyst
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Conversion of FUR
Selectivity of 2
Selectivity of 4
100
100
80
60
40
20
Conversion of FUR
Selectivity of 2
Selectivity of others
90
80
70
60
50
40
30
20
10
0
0
1
2
3
4
5
6
0
1
2
3
4
5
Reaction time / h
Catalytic run
Figure 7. Effect of reaction time in the ^FUR-ethanol-O2 system
(Reaction conditions: 0.20 g FUR, 50 mg catalyst, 50 mg K2CO3, 15
mL ethanol, under 0.3 MPa of O2, T=140 ºC)
Figure 8. Recycling of the Fe@C catalyst in oxidative condensation
of FUR with ethanol (Reaction conditions: 0.20g FUR, 50 mg catalyst,
50 mg K2CO3, 15 mL ethanol, 140 ºC, under 0.3 Mpa of O2, for 4 h)
Catalytic hydrogenation of FUR in alcohol with the Fe@C catalyst
The recycling of Fe@C catalyst has been examined for the oxidative
condensation of FUR with ethanol. After the catalytic reaction, the
catalyst was separated, and washed with anhydrous ethanol, and
then dried at 80 °C for 12 h overnight before being reused in the
next run. As shown in Figure 8. It is seen that the conversion of FUR
drops to ca. 70%. In the following, the recycling catalyst is thermal
reduction at 450 °C for 4h under hydrogen atmosphere after being
washed by anhydrous ethanol and dried, and then for the third run.
As a result, it is found that the conversion of FUR raised about 83%
again and selectivity of 2 is ca. 85% for the oxidative condensation.
The fourth and fifth run is similar with the former process, and the
obtained results keep same trend. These results showed that the
Fe@C catalyst can reused and recycled when it is treated using the
same method as treatment process of the Fe-EDTA sample. In
addition, the TEM images of the catalyst also confirm that iron
nanoparticles are surrounded by carbon layers and there is no
structural change or agglomeration occurred after being used.
These indicate that the basic structure of the Fe@C catalyst can
keep stable during the reaction.
Next, the hydrogenation of FUR in aliphatic alcohol was investigated
using similar catalyst system. The equation is indicated in Scheme 2,
and the obtained main products are furfuryl alcohol (4) and
tetrahydrofurfuryl alcohol (5). Table 4 presents the experimental
results in the presence of different catalysts. In the absence of any
catalyst, only 29.8% conversion of FUR and 10.6% selectivity of 4 is
obtained. When the Fe/C and K2CO3 is employed as the catalyst, the
conversion of FUR and selectivity of 4 arrived at 99.9% and 93.6%,
respectively. To our joy, a more than 99% conversion in 83.2%
selectivity of 4 was obtained with single Fe@C as catalyst. In
addition, Fe-EDTA also exhibits a considerable activity where a 95.6%
conversion of FUR with 85.5% selectivity of 4 is attained under
similar conditions. However, in the presence of single Fe3O4 catalyst,
the conversion of FUR and selectivity of 4 were 68.4% and 88.9%,
respectively. The above results showed that the Fe atom was the
active centre for the hydrogenation of FUR in ethanol and the
complex Fe-EDTA is more easily reduced than the Fe3O4 compound
during reaction. In addition, when the Co@C and Ni@C are used as
catalysts, both the conversions of FUR and selectivities of 4 are near
to those obtained using Fe@C catalyst, which is very different with
the oxidative condensation reaction. Also, Pt/C and Ru/C catalysts
provide the roughly identical catalytic activity and only product
selectivity have a slight difference in reaction. On the other hand, it
needs to be mentioned that the main product is the compound 5
and the corresponding selectivity arrives at 99% when Pd/C catalyst
is employed in hydrogenation of FUR.
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Table 5. Influence of solvent in the hydrogenation of FUR with
Fe@C catalyst [a]
[b]
Entry Reaction medium Conv. (%)
Selectivity of 4 (%)[b]
Scheme 2. Reaction equation of hydrogenation of FUR with H2
1
2
3
4
5
6
7
8
9
methanol
n-propanol
i-propanol
n-butanol
2-butanol
n-pentanol
n-hexanol
DMF
61.1
96.9
98.5
98.4
99.1
97.7
98.5
97.3
87.2
90.2
84.8
86.5
81.4
80.2
64.9
71.2
77.1
75.4
Table 4. Selective hydrogenation of FUR using different catalysts a
Selectivity(%) b
Entry
Catalyst
Conv. (%) b
4
5
others
89.4
3.7
1
2
/
Fe@C + K2CO3
Fe@C
29.8
99.9
>99
95.6
68.4
>99
>99
>99
>99
>99
10.6
0
93.6 2.7
83.2 0.4
3
16.4
14.5
8.9
THF
4
Fe-EDTA
Fe3O4
85.5
0
[a] Reaction Conditions: FUR 0.20g, catalyst 50 mg, 15 mL solvent, 220 ºCÈ2 Mpa
of H2, for 4 h.
5
88.9 2.2
81.6 1.9
79.6 2.3
94.6 2.3
62.3 11.7
[b]
The experimental results are obtained by GC with the internal standard
methods.
6
Co@C
Ni@C
12.5
18.1
3.1
Finally, we also conducted a reusable experiment on the catalytic
hydrogenation of FUR with Fe@C. After the first run, the solid
catalyst was separated by magnet, and washed with anhydrous
ethanol, and then dried at 80°C for 12 h overnight before being
reused in the next run. The corresponding results are displayed in
the Figure 9, It could be seen that Fe@C has its excellent recycling
performance, and it still keeps a high catalytic performance (a 99%
FUR conversion and about 80% selectivity of 4) after being recycled
for six times, which is very efficient and stable.
7
8
Pt/C
9
Ru/C
26
10
Pd/C
0
>99
0
a Reaction Conditions: FUR 0.20g, catalyst 50 mg, K2CO3 50 mg, in 15 mL C2H5OH,
at 220 ºC, under 2 Mpa of H2, for 2 h.
b
The experimental results are obtained by GC with the internal standard
methods.
Furthermore, the influence of solvent was investigated in the
hydrogenation of FUR with Fe@C and the data are presented in
Table 5. As a result, it was found that a 61.1% conversion of FUR in
a 90.2% selectivity of 4 is obtained in methanol. It indicates that the
methanol is beneficial to the production of 4 in reaction. Moreover,
the results using n-propanol, iso-propanol, n-butanol and 2-butanol
are very similar with that attained in ethanol. However, the
selectivity of 4 becomes low when the hydrogenation is performed
in n-pentanol or n-hexanol solvent. These show that the longer
carbon chain is disadvantageous to the generation of 4 in this
catalyst system. Besides, when DMF and THF are used, both the
conversion of FUR and selectivity of 4 are declined compared to
those obtained using the Fe@C as catalyst.
Conversion of FUR
Selectivity of 4
100
80
60
40
20
0
1
2
3
4
5
6
7
Catalytic run
Figure 9. Recycling experimental results of Fe@C catalyst for the
hydrogenation of FUR in ethanol (Reaction conditions: 0.20 g FUR,
50 mg Fe@C, 15 mL C2H5OH, at 220 ºC, under 2 Mpa of H2, for 2 h)
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Reaction mechanism for transformation of FUR with Fe catalyst
iron-based catalyst is prepared with
a combination of the
solvothermal synthesis method and in situ hydrogen reduction
process. In general, a mixture of 9.69 g Fe(NO3)3ñ9H2O, 4.47 g
Na2EDTA, and 0.48 g NaOH are dissolved in 30 mL deionized water.
Then, 10 mL methanol was added to the aqueous solution under
stirring at room temperature. After the red homogeneous solution
is formed, the mixture is transferred to 60 mL stainless steel
autoclave and sealed, followed by a static hydrothermal treatment
at 200 °C for 24 h. he generated precipitates are centrifuged and
washed with deionized water and acetone three times, respectively.
The obtained dark red solid is placed into vacuum oven and dried
overnight at 105 °C, which is referred to as the Fe-EDTA. At last, the
Fe-EDTA is further heat-treated and reduced with a 2 °C/min rate
and kept for 240 min at 450 °C in a 50 mL/min H2 flow. After being
cooled to room temperature, the obtained solid nanoparticle is
magnetic and referred as the Fe@C catalyst.
Based on the results of control experimental results and catalytic
principle of the reaction, a possible reaction mechanism for
transformation of FUR is provided in Scheme 3. 1) Under O2
atmosphere: Firstly, the hydrogen transfer process occurs between
FUR and ethanol, in which a certain amount of acetaldehyde and
the compound
4 can be generated; in the following, the
condensation is performed between the left FUR and the generated
acetaldehyde; meanwhile, the compound 4 can be oxidized to FUR
by molecular oxygen. The data of entries 13-16 in Table 1 show that
the Fe@C catalyst should be responsible for hydrogen transferring
process and the selective oxidation of 4 to FUR in this reaction.
Correspondingly, the role of K2CO3 is promoting the next
condensation reaction to produce 2 as target product. 2) Under H2
atmosphere: firstly, the gaseous hydrogen is diffused to the surface
of Fe nanoparticle in which H2 molecule is activated; then, the
hydrogen transferring happens between the aldehyde group of FUR
and the activated H2 on the surface of catalyst, and the compound 4
can be generated. In addition, the furan ring of formed 4 can be
further hydrogenated to produce the compound 5 as the by-
product owing to the existence of numerous active H atom.
Correspondingly, the Fe@C catalyst should be responsible for the
activation of hydrogen in this process. If K2CO3 was added, the
hydrogenation of furan ring may be depressed and the selectivity of
compound 4 is further elevated.
The Co@C and Ni@C catalyst is prepared with a solvothermal
synthesis method and in situ hydrogen reduction process. The
Fe/AC, Pd/C and Pt/C are prepared by impregnation method with
activated carbon as the support.
General procedure for catalytic transformation of FUR In a typical
process for the oxidative condensation of FUR, a stainless steel
autoclave (120 mL) equipped with a magnetic stirring was charged
by the catalyst (0.050 g), FUR (0.200 g), ethanol (15 mL), K2CO3
(0.050 g). The atmosphere in the autoclave was replaced by pure O2
after reactor being sealed. Then the oxygen is charged to about 0.3
MPa at room temperature. In the following, the autoclave is heated
to 140 °C, and kept for 4 h. After reaction, the autoclave was cooled
down to the room temperature slowly and the solid catalyst was
separated from the reaction mixture by magnet. In a typical process
for the hydrogenation of FUR, a stainless steel autoclave (120 mL)
equipped with a magnetic stirring was charged by the iron catalyst
(0.050 g), FUR (0.200 g), ethanol (15 mL), K2CO3 (0.050 g). The
atmosphere in autoclave was replaced by nitrogen and pure H2
after reactor being sealed. Then the hydrogen is charged to about
2.0 MPa at room temperature. In the following, the autoclave is
heated to 220 °C, and kept for 2 h. After reaction, the reaction
solution is cooled down to room temperature slowly and the iron
catalyst is separated from the mixture by magnet.
The products are analyzed by an Agilent 7890 GC equipped with a
HP-5 column and a FID detector, and the specific structural
characteristics of the products are identified by GC-MS (Agilent
7890/5975C).
The yield and selectivity of main product are calculated and defined
as follows:
Conv.(%)= The total
amount of furfural Fthe left amount of furfural
× 100%
The total amount of furfural
The molar amount of product
Sel. (%) = The total
× 100%
Scheme 3. Possible reaction mechanisms for transformation of FUR
molar amount of furfural
The characterization of catalyst The morphologies, structure, and
chemical compositions of the as-prepared products were
investigated using a scanning electron microscope (SEM: JSM-6301F,
JEOL), equipped with a JED-2300 (JEOL) EDXS spectrometer for
chemical analysis, and transmission electron microscope (TEM:
JEM-2100, JEOL). The powder X-ray diffraction (XRD) patterns for
qualitative phase analysis were recorded with a Rigaku D/max-IIIA
in ethanol under O2 or H2 atmosphere
Experimental
The preparation of catalysts All the chemicals are of analytical
grade and directly used after purchase without purification. The
8 | J. Name., 2012, 00, 1-3
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DOI: 10.1039/C8GC00852C
Journal Name
ARTICLE
etc.
1
2
diffractometer (Cu-YrU „ A íXñðìñò )• ]v šZꢀ î} ŒꢁvPꢀ }( ñ-80°. For
the precursors, the data were collected in the range of 5-80° with a
•šꢀ‰ Á]ꢂšZ }( ìXìñ£lî}X C}Œ šZꢀ solid catalysts, the data are
collected in the range from 5-80° with a •šꢀ‰ Á]ꢂšZ }( ìXìñ£lî} as
well. FT-IR spectra (KBr pellets) are recorded on a Perkin-Elmer
Spectrometer in the range 4000-400 cm-1. BET surface areas, pore
volumes, and the average pore diameters of the prepared samples
are obtained from N2 (77.3 K) adsorption measurements by using a
Micromeritics ASAP2020M system, in which the samples are
pretreated under vacuum at 150 °C for 4 h. The average pore
diameters are calculated according to Barrett-Joyner-Halenda (BJH)
model in adsorption and desorption period. Thermol gravimetric
analysis (TGA) are performed on NETZSCH-TG209 F3 using flowing
N2. Samples are dried at 120 °C for 24 h prior to analysis, and then
20 mg samples are heated at a heating rate of 10 °C/min from 40 °C
to 1000 °C.
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In summary, a novel iron-based solid catalyst is developed
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also catalyze the hydrogenation of FUR in aliphatic alcohol
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compound was attained under the suitable conditions. It
2
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In accordance with our policy on Conflicts of interest please
ensure that a conflicts of interest statement is included in your
manuscript here. Please note that this statement is required
for all submitted manuscripts. If no conflicts exist, please state
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Acknowledgements
This research work is financially supported by Tianjin Research
Program of Application Foundation and Advanced Technology
(No. 17JCYBJC20200) and the State Key Program of the
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Notes and references
• Footnotes relating to the main text should appear here. These
might include comments relevant to but not central to the
matter under discussion, limited experimental and spectral data,
and crystallographic data.
§
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Green Chemistry
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DOI: 10.1039/C8GC00852C
Versatile catalysis of Iron: tunable and selective transformation of
biomass-derived furfural in aliphatic alcohol
Zhenya Zhang a, Xinli Tong,*a Haigang Zhang a and Yongdan Li b
a Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry
and Chemical Engineering, Tianjin University of Technology, No. 391 Binshuixi Road, Tianjin
300384, P. R. China. Fax: (+)86-22-60214259; Tel: (+86)-22-6024259; E-mail: tongxinli@tju.edu.cn;
tongxli@sohu.com .
b School of Chemical Engineering, Tianjin University, No. 92, Weijin Road, Tianjin 300372, P. R.
China.
Graphical Abstract
A highly efficient and catalytic valorization of biomass-derived furfural to produce value-added
chemicals has been developed with the Fe@C catalyst under O2 or H2 atmosphere.