Catalytic cascade conversion of furfural to 1,4-pentanediol in a single reactor

Article abstract of DOI:10.1039/c8gc00039e

The synthesis of bio-based linear diols is the subject of many research studies. However, one of the main obstacles in industrial development is the difficulty in controlling product selectivity. Here, we report the catalytic conversion of furfural to 1,4-pentanediol (PD) in the presence of Ru supported on an ordered mesoporous carbon (CMK-3) under pressure of H₂ and CO₂ in water. In contrast to previous catalytic pathways, this work is distinct in that it yields 1,4-PD as an exclusive product, instead of a mixture of 1,2- and 1,5-PD as usual. Under optimized conditions, 1,4-PD was obtained in 90% yield, and in a one-pot reaction, directly from furfural. We disclose that the conversion of furfural to 1,4-PD followed an unusual catalytic route. It implies a bifunctional catalytic pathway based on sequential catalytic hydrogenation reactions and an acid-catalyzed Piancatelli's rearrangement.

Full text of DOI:10.1039/c8gc00039e

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ARTICLE
Catalytic cascade conversion of furfural to 1,4-pentanediol in a
single reactor
Received 00th January 20xx,
Accepted 00th January 20xx
a
a,b
a
c
d
a
a
a
a
Fei Liu,
‡
Qiaoyun Liu,
‡
Jinming Xu, Lei Li, Yi-Tao Cui, Rui Lang, Lin Li, Yang Su, Shu Miao,
a
a
a
e
a
Hui Sun, Botao Qiao,* Aiqin Wang,* Francois Jerome* and Tao Zhang
DOI: 10.1039/x0xx00000x
The synthesis of bio-based linear diols is the subject of many researches. However, one of the main obstacles in industrial
development is the difficulty in controlling the product selectivity. Here, we report the catalytic conversion of furfural to
www.rsc.org/
1
,4-pentanediol (PD) in the presence of Ru supported on an ordered mesoporous carbon (CMK-3) under pressure of H
2
and CO in water. In contrast to previous catalytic pathways, this work is distinct in that it yields 1,4-PD as an exclusive
2
product, instead of a mixture of 1,2- and 1,5-PD as usual. Under optimized conditions, 1,4-PD was produced in 90% yield,
and in a one-pot reaction, directly from furfural. We disclose that the conversion of furfural to 1,4-PD followed a unusual
catalytic route. It implies a bifunctional catalytic pathway based on sequential catalytic hydrogenation reactions and an
acid-catalyzed
Piancatelli’s
rearrangement.
occurs to a more or less extent depending on the catalyst. On
the other hand, these catalytic routes afford mainly 1,2 and
Introduction
1
,5-PD, often as a mixture of both, in a 50-80% yield (1,2 + 1,5-
Linear diols are of outmost importance in chemistry and find
nowadays many applications in our society. In particular, diols
PD) (Figure 1). As a general trend, metals on basic supports
16
1
2
15
such as Pt/HT , Cu/LDO and Pt/CeO
1
are widely employed as solvent in cosmetic industry. They
2
afford mainly 1,2-PD
1
4
while metals on acid supports such as Pd-Ir-ReO
1
Rh-Ir-ReO /SiO
x 2
x
/SiO
2
and
also serve as intermediates in the manufacture of
fine/specialty chemicals, as monomers in the fabrication of
7
are more selective to 1,5-PD (Table S1). So
2
far, none of these catalysts are able to produce selectively 1,4-
PD. For instance, only a maximum yield of 30% in 1,4-PD was
polymers and as polar head in the synthesis of biosurfactants.
To date, linear diols are produced on an industrial scale from
fossil-based resources. The rapid emergence of plant-based
industry is now opening opportunities to produce bio-based
linear diols, often with a similar chemical structure to diols
from a fossil origin, but with a much improved carbon
x 2
claimed from furfural over a Pd-Ir-ReO /SiO bifunctional
1
4
catalyst. In contrast to 1,2- and 1,5-PD, 1,4-PD is currently
not produced (industrially speaking) from fossil oils which
open business opportunities in term of product development.
At a labscale, 1,4-PD and its precursor (3-acetyl-1-propanol, 3-
AP) were reported as valuable organic building blocks, in
particular in the synthesis of chloroquine, one of the most
effective medicines for both prevention and treatment of
3
-7
footprint.
reported, the synthesis of bio-based pentanediol (PD) from
Among the different strategies previously
8
-
industrially available furfural has attracted particular interest.
1
To date, current catalytic strategies involves the
hydrogenolysis of the C-O bond of the furanic ring in the
0
1
8
malaria. Switching the selectivity of the current catalytic
processes from 1,2/1,5-PD to 1,4-PD is not an easy task and it
requires searching novel catalytic pathways. 1,4-PD was
previously synthesized through catalytic hydrogenation of
1
1-14
presence of a metal-based catalyst.
This catalytic pathway
takes place at relatively high temperatures (100-170 °C) and
pressures of H2 (3-6 MPa). Under these harsh reaction
conditions, over-hydrogenation/hydrogenolyis reaction also
levulinic acid (LA) or
5 MPa of H in the presence of metal catalysts such as Ru,
Pt/Mo, Rh/Mo and Cu, to mention a few.
moderate to good yields (70-96%) were claimed, the
availability and/or the current price of levulinic acid or
γ-valerolactone at 80-200 °C and under 6-
1
2
1
9-23
Although
γ
-
valerolactone are still important limitations for such
application.
Finding innovative catalytic routes capable of converting
selectively furfural to 1,4-PD in a one pot process would
definitely increase the attractiveness of the furfural platform
for the supply of bio-based PD. To reach this objective, two
criteria should be fulfilled: (1) identifying a novel reaction
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pathway to switch the selectivity of the reaction from 1,2/1,5- S2 and S3). For the un-reduced Ru/CMK-3 catalyst, the average
PD to 1,4-PD and (2) designing solid catalysts able to promote particle size is 0.9 nm, while it is 1.0 nm for the Ru/CMK-3-
this reaction under mild conditions to prevent over- R200 and 3.8 nm for the Ru/CMK-3-R400, indicating that the
o
reduction at mild conditions (e.g., 200 C) does not cause the
hydrogenation/hydrogenolysis reactions of PD or furfural.
This work addresses this issue and we disclose here a obvious growing of Ru nanoparticles while a higher reduction
o
catalytic pathway capable of selectively converting furfural in a temperature (e.g., 400 C) leads to agglomeration of Ru
one pot process to 1,4-PD in the presence of Ru supported on nanoparticles.
an ordered mesoporous carbon so-called CMK-3 (Figure. 1).
This catalytic route involves a series of cascade hydrogenation
and acid-catalyzed reactions. Hydrogenation reactions were
catalyzed by Ru nanoparticles while acid sites stemmed either
from the CMK-3 support or the acidification of water with CO
2
2
4
as previously reported.
Thanks to the mild reaction
o
conditions (60-80 C and 1 MPa H ), 1,4-PD is selectively
2
obtained in yield up to 90%. To the best of our knowledge, this
work constitutes an important advance in the field by opening
the first selective access to 1,4-PD from furfural.
Figure 2. HAADF-STEM images of Ru/CMK-3-unred (A, A’),
Ru/CMK-3-R200 (B, B’) and Ru/CMK-3-R400 (C, C’) and the
corresponding size distributions.
The oxidation states of Ru species were probed by X-ray
absorption spectroscopy as it is sensitive to both the chemical
state and the local structure of the measured metals.
Considering that the reduced Ru species might be easily re-
oxidized upon exposure to air, we performed an in situ
measurement. The reduction procedure is slightly different
Figure 1. Originality of this work.
Results and discussion
from that for the TPR treatment. In this condition, a 5% H /He
2
was used and the samples were reduced for 20 min at each
temperature (for more details, see supporting information).
The near edge (XANES) presented in Figure S4 suggest that the
Ru species on the un-reduced Ru/CMK-3 sample exist in an
The ordered mesoporous carbon (CMK-3) support was
synthesized by a hard-templating method using 2D hexagonal
2
5
SBA-15 as an inorganic template, as described previously.
More information on the synthesis of CMK-3 is provided in the
SI. The Ru species were introduced on the CMK-3 by an
impregnation method with an actual Ru loading of 2 wt%. The
oxidation state lower than +4 since the edge is lower than that
o
of RuO . After reduction at 200 C, the Ru species were slightly
2
reduced but still in a positively charged state. However, with
o
reduction at 400 C, Ru was almost completely reduced to
2
sample was treated thermally at 300 °C in N flow for 3 h
yielding the so-called Ru/CMK-3-unred. The Ru/CMK-3-unred
catalyst was then subjected to a temperature programmed
metallic state as its edge almost coincides with that of the Ru
foil. A quick fitting of the spectra further confirmed this
conclusion (Table S2). In Ru/CMK-3-unred sample, besides Ru-
Ru bond, there are Ru-Cl and Ru-O bonds which should
2
reduction (TPR) treatment under 10% H /He gas from ambient
temperature to 200 and 400 °C, and denoted hereafter
Ru/CMK-3-R200 and Ru/CMK-3-R400, respectively.
3
originate from the RuCl precursor and the interaction of Ru
The X-ray diffraction (XRD) patterns of pure CMK-3 and
Ru/CMK-3 catalysts showed that all samples presented only
with O-containing group on the CMK-3, respectively. In
Ru/CMK-3-R200 sample, Ru-Cl bonds are still observed while
the Ru-O bond disappeared, consistent with a partial reduction
of Ru. In Ru/CMK-3-R400 catalyst, only Ru-Ru bond was found,
suggesting that Ru was fully reduced to form metallic Ru, in
line with the near edge results. In addition, on Ru/CMK-3-R400
sample, the coordination number of Ru-Ru was fitted to be
o
two broad peaks at around 23 and 43 which were ascribed to
o
2
6
the amorphous carbon (Figure S1) . It should be noted that no
Ru diffraction peak was observed on all Ru/CMK-3 samples,
suggesting that Ru species are highly dispersed on the support.
To verify this, high-angle annular dark-field (HAADF) scanning
transmission electron microscopy (STEM) was further used to
characterize the Ru species. Typical HAADF-STEM images show
that Ru nanoparticles are uniformly dispersed on the CMK-3
support, and the particle size distribution depends on the
pretreatment conditions (Figure 2, and more images see Figure
1
0.2. Considering that Ru has a very similar atomic radius to Pt,
it could be roughly calculated, based on the coordination
2
number according to a previous report, that the size of Ru
7
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NPs is about 3 nm. This value agrees well with the STEM when the partial pressures of CO
ARTICLE
2
2
and H were adjusted to 3
results described above.
MPa and 1 MPa, respectively (entry 3-4). This result suggests
The acid sites of the catalysts were probed with NH
3
-TPD that the acidification of the reaction media (in situ formation
experiments and the results are shown in Figure S5 and Table of carbonic acid) had a positive effect on the selectivity to 1,4-
S3. The acid density varies with the reduction temperature, PD. Interestingly, when the partial pressure of CO was further
and the Ru/CMK-3-R200 has the maximum acid density (425 increased (CO /H : 3.5/0.5 MPa), the conversion of furfural
μmol/g), followed with Ru/CMK-3-unred (271 μmol/g) and dropped down to 82% and the yield of 1,4-PD went down to
Ru/CMK-3-R400 (205 μmol/g). In contrast, the blank CMK-3 57% (entry 5). Furthermore, without H , no 1,4-PD was
support has the lowest acid density (61 μmol/g), indicating formed, indicating that the direct conversion of furfural to 1,4-
2
2
2
2
2
8
that the acidity stems mainly from Ru species. Comparing the PD presumably followed a bifunctional acid/hydrogenation
trend of acid density with that of Ru valence state, we can catalytic route. More information on the reaction mechanism
conclude
is provided below. It is worth noting that compared to the best
that the acidity arises mainly from the positively charged results reported so far for the production of 1,2- and 1,5-PD
2
8
Ru species, which is in accordance with the previous reports.
from furfural (Table S1) and even 1,4-PD from LA (Table S4),
The NH -TPD profiles (Figure S5) show that both Ru/CMK-3- the 1,4-PD yields obtained in this work are among the best
3
unred and Ru/CMK-3-R200 contain primarily weak acid sites.
ones, essentially thanks to the mildest conditions of pressures
In a first set of experiments, furfural was hydrogenated in and temperatures.
water in the presence of the Ru/CMK-3-R200 catalyst (0.57
The mesopores plays an important role on the activity and
mol% of Ru). Results are summarized in Table 1. At 80 °C and a selectivity of Ru/CMK-3-R200. When SBA-15 (template) was
pressure of H of 1 MPa, furfural was consumed completely removed during the preparation of the catalyst, Ru dispersed
2
after 20 h of reaction (entry 1). Unexpectedly, 1,4-PD was over a microporous carbon was obtained and denoted
formed as the major product (61 % yield), suggesting that this hereafter Ru/C. In the presence of this Ru/C, no 1,4-PD was
catalytic process did not occur through
a
classical produced (Table 1, entry 6). Instead, FA (26% yield), THFA (11%
hydrogenolysis mechanism. The only other detectable product yield), 3-AP (10% yield) and 20% of unidentified chemicals
was THFA (17% yield), resulting from the over-hydrogenation were observed. The lower BET surface and the lower amount
of furfural. The 22% unidentified carbon revealed that side of acid sites (91 ꢀmol/g) on Ru/C may explain this difference of
reactions concomitantly took place. When the H pressure was catalytic performances with Ru/CMK-3-R200 (supporting
2
increased to 4 MPa, the yield to 1,4-PD remained unchanged. information).
However, under these conditions, THFA was formed in 35%
To collect more information on the role of Ru, the un-
yield (entry 2), and only less than 5% of unknown products reduced Ru/CMK-3 and the Ru/CMK-3-R400 were also tested
were formed. To our delight, when the reactor was pressurized under the optimized conditions (entries 7 and 8). Evidently,
with 2 MPa of CO and 2 MPa of H (total pressure of 4 MPa), the un-reduced Ru/CMK-3 influences negatively the rate of the
2
2
the yield to 1,4-PD was increased to 71% and further to 90% hydrogenation step and in this case, acid-catalyzed reaction
[
a]
Table 1. Optimization of the reaction parameters over Ru/CMK-3 catalyst.
d
CO
2
/H
2
Conv.
(%)
1.4-PD
THFA
FA
3-AP
Others
Productivity
Entry
Catalyst
-1
-1 -1
2
b
(
mol .g h )x10
(
MPa/MPa)
Yield (%) Yield (%) Yield (%)
Yield (%)
Yield (%)
Ru .
1
2
3
4
5
6
7
8
Ru/CMK-3-R200
Ru/CMK-3-R200
Ru/CMK-3-R200
Ru/CMK-3-R200
Ru/CMK-3-R200
Ru/C
0/1
100
100
100
100
82
61
61
71
90
57
0
17
34
18
9
0
0
0
0
22
5
5.3
0/4
2/2
3/1
5.3
6.2
7.8
4.1
0
4
0
7
0
0
1
3.5/0.5
3/1
8
0
15
10
0
2
67
11
10
15
35
26
0
20
15
50
18
Ru/CMK-3-unred
Ru/CMK-3-R400
Ru/CMK-3-R400
3/1
100
100
100
75
35
6
6.5
3.0
0.5
3/1
0
0
c
9
3/1
0
41
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
o
[
a] Reaction conditions: 2 wt% furfural in H O, 5 mL H O, 20 h and a metal/substrate ratio of 0.57 mol% at 80 C; [b] others products
2 2
stem either from over-hydrogenation reactions (C-C bond cracking) or acid-catalyzed degradation of intermediates leading to the
Please do not adjust margins
o
formation of oligomeric and tar-like products; [c] at 60 C; [d] Productivities (mol product per g of Ru and per hour).

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occurred dominantly leading to the conversion of furfural to
undesirable side products; the yield in 1,4-PD dropped from 90
to 75% (entry 7). As can be seen in Figure S6, Ru/CMK-3-R200
100
Conv.
1,4-PD
and Ru/CMK-3-R400 exhibited
a
similar activity (97%
3-AP
THFA
FA
8
0
conversion vs 92% after 5 hours of reaction for Ru/CMK-3-
R200 and Ru/CMK-3-R400, respectively). However, Ru/CMK-3-
R200 was significantly more selective into 3-AP and 1,4-PD
others
60
than
Ru/CMK-3-R400,
this
latter
favoring
over-
40
hydrogenation/hydrogenolysis reactions. Lowering the
o
reaction temperature to 60
C partly inhibited over-
2
0
hydrogenation/hydrogenolysis reactions with Ru/CMK-3-R400,
but the yield to 1,4-PD remained as low as 6% (entry 8). This
result suggested that Ru/CMK-3-R400 catalyst has a higher H2
activation ability than Ru/CMK-3-R200 which is partly reduced
only. In order to verify this claim, a microcalorimetric
0
a
a
a
b
100
60
40
60
o
Temperature( C)
2
9
measurement of H adsorption was carried out. Amount of Figure 3. Effects of reaction temperature on the conversion of
2
-1
·g
adsorbed H on both samples were small, i.e., ~2 μmol
2
on furfural and the yields of products in the presence of Ru/CMK-
-1
Ru/CMK-3-R200 and ~10 μmol·g
on Ru/CMK-3-R400, 3-R200. [a] Reaction conditions: 2 wt% furfural in H O, 5 mL
2
respectively. However, the adsorption strength was totally H2O, 20 h and a metal/substrate ratio of 0.57 mol%. [b]
different: initial adsorption heat on Ru/CMK-3-R200 was about Reaction time 30 h.
-
1
3
0 kJ·mol whereas on Ru/CMK-3-R400 a value of about 70
-1
kJ·mol was determined which is similar to the adsorption
3
heat on Pd/C catalyst. These results demonstrated that
0
A
Ru/CMK-3-R200 is less active for H activation than Ru/CMK-3-
2
R400 and this moderate H2 activation ability is crucial to
achieve high selectivity into 1,4-PD. The difference in the
capability for H2 activation is closely associated with the
electronic property of Ru. The valence state of Ru decreases in
the order of Ru/CMK-3-unred > Ru/CMK-3-R200 > Ru/CMK-3-
R400 (Figure S4), which is in reverse order with the initial
0
adsorption heat of H , indicating that metallic Ru is
2
responsible for hydrogenation.
The recyclability of the Ru-CMK-3-R200 did not reveal any
decrease of its catalytic activity cycle after cycle. However, the
selectivity to 1.4-PD started decreasing after 3 catalytic cycles
B
(Figure S7), suggesting a change in the catalyst chemical
composition. A hot filtration test revealed that it was a truly
heterogeneously-catalyzed process meaning that a proper
reactivation of the Ru-CMK-3-R200 will be thus required for
long term recycling.
To elucidate this unexpected reaction pathway observed
with Ru/CMK-3-R200, the temperature of the reaction was
varied (Figure 3). In agreement with the Arrhenius’s law, the
temperature has an important effect on the reaction progress.
2 2
At 100 °C (CO /H : 3/1 MPa), THFA was formed in a higher
proportion due to the enhanced hydrogenation ability of
Ru/CMK-3-R200 at this temperature. In contrast, at 60 °C, 3-AP
was formed as a dominant product (73% yield, and even 84% Figure 4. Kinetic time course of the furfural transformation in
o
o
at prolonged reaction time) while at 40 °C, FA was observed as the presence of Ru/CMK-3-R200 at 60 C (A) and 80 C (B).
the main product (70%). Note that the 3-AP yield obtained at Reaction condition: furfural (0.1g), H O (5 mL), CO /H
0 °C is comparable to or even better than those reported 3MPa/1MPa, a metal/substrate ratio of 0.57 mol%.
2
2
2
:
6
from previous works involving bacteria or homogenous
catalysts (Table S5) using LA, alkynes and even 1,4-PD as a
To support this claim, we plotted the yield of FA, 3-AP and
3
1-36
o
Altogether, these results suggest that the 1,4-PD versus time at both 80 °C and 60 C (Figure 4). At 60 C,
o
starting material.
catalytic conversion of furfural to 1,4-PD involves a cascade of FA was selectively formed with 82% yield up to 8 hours of
reactions with FA and 3-AP being two important reaction. At prolonged reaction time, the FA yield decreased
intermediates.
gradually with a concomitant increase of the 3-AP yield up to
4
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8
4% at 30 hours accompanied with the formation of a small tar-like materials such as humins and/or oligomers of FA. 4-
o
amount of THFA and a negligible 1,4-PD generation. At 80 C, HCP can be obtained through the Piancatelli rearrangement of
the conversion of furfural reached 90% after 5 hours of FA. In contrast to the conversion of FA to LA that typically
reaction. Main products were in this case FA and 3-AP, occurs in the presence of strong acid sites, the Piancatelli
accompanied by a small amount of THFA and 1,4-PD (Figure rearrangement of FA is generally favored by the presence of
3
9-41
3
b). At prolonged reaction time, both FA and 3-AP were weak acid sites.
In good agreement, when the reaction was
/H O in the absence of Ru/CMK-3-R200
consumed and the yield of 1,4-PD increased gradually to reach conducted under CO
2
2
a maximum of 90% after 20 h of reaction. These kinetic catalyst, 4-HCP was still produced as a major product, although
profiles revealed clearly that the catalytic process involves the at a different rate. From a catalytic point of view, this result
following sequence (1) a hydrogenation of furfural to FA indicates that Ru/CMK-3-R200 exhibit weak acid sites,
followed by (2) the conversion of FA to 3-AP and then (3) otherwise LA would have been produced as a major product.
hydrogenation of 3-AP to 1,4-PD. In our case, the weak acid sites required for the reaction are
In aqueous acidic media, it is generally believed that FA can thus provided by both the positively charged Ru species and
3
react with water to form LA. Therefore, one possible route is the water-dissolved CO2.
7
the conversion of FA to LA, LA to 3-AP and finally 3-AP to 1,4-
From all these results, a plausible reaction pathway may be
PD. However, in the kinetic profiles presented in Figures 3 and proposed to explain this unexpected and selective conversion
4, no LA was detected, suggesting that in our reaction of furfural to 1,4-PD instead of 1,2 or 1,5-PD as usual. The first
conditions either LA was not an intermediate or its in situ step is the hydrogenation of furfural to FA. Then, FA
hydrogenation to 3-AP was quasi instantaneous. To check this underwent a Piancatelli rearrangement catalyzed by weak
possibility, we then performed the reduction of LA in the acids present on Ru/CMK-3-R200 or generated by dissolving
identical optimized conditions reported in Table 1, entry 4. To CO into water (in situ production of carbonic acid). The overall
2
our surprise, neither 3-AP nor 1,4-PD were generated, and Piancatelli transformation is believed to proceed through a
instead LA was converted to γ-valerolactone in 95% yield cascade sequence that terminates with a 4π electrocyclic ring
(Figure S8A).
A
control experiment under identical closure of a pentadienyl cation, as shown in Figure S9. Under
experimental conditions but with γ-valerolactone as the our reaction conditions, we propose that the pentadienyl
starting material was further carried out and the result showed cation was trapped in situ by hydrogenation over Ru/CMK-3,
also that no conversion occurred at all within a 20-hour test yielding 3-AP and then 1,4-PD. This reaction pathway is
(Figure S8B). This result is consistent with published reports displayed in figure 6.
which have indicated that the hydrogenation of γ-
valerolactone over Ru-based solid catalysts required harsher
3
8
conditions of pressure and temperature than ours.
Figure 6. Proposed mechanism for 1,4-PD synthesis in the dual
acid/hydrogenation catalytic system.
Conclusions
We demonstrate that the hydrogenation of furfural at 80 °C
2 2
over Ru/CMK-3-R200 in water and under a CO /H pressure
Figure 5. Kinetic time course of the FA conversion in CO
o
system at 80 C in the absence of hydrogen.
2
/H
2
O
permitted an access to 1.4-PD in yield up to 90%. This catalytic
route is distinct from previous strategies in that it exclusively
affords 1,4-PD instead of a mixture of 1,2- and 1,5-PD as usual.
Next, the reaction was examined from FA in the presence In addition, the mild conditions of pressure and temperature
of the Ru/CMK-3-R200 catalyst under the same reaction required in our strategy suppresses unwanted over-
2
conditions but in the absence of H . As shown in the kinetic hydrogenation/hydrogenolysis reactions which is often an
profile presented in Figure 5, under these conditions, 4- important limitation of the current catalytic processes con-
hydroxy-2-cyclopentenone (4-HCP) was formed with ~25% verting furfural to 1,2/1,5-PD. We discovered that the conver-
yield after 1h of reaction. LA was concomitantly formed but at sion of furfural to 1,4-PD followed a catalytic pathway unre-
a much lower rate. Other products were soluble and insoluble ported to date. It implies a bifunctional catalytic pathway: (1) a
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catalytic hydrogenation of furfural to FA follows by (2) an acid- 7.
catalyzed Piancatelli-type rearrangement yielding 3-AP, after in
M. Zheng, J. Pang, A. Wang, T. Zhang, Chin. J. Catal., 2014,
5, 602-613.
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8
.
situ hydrogenation of the pentadienyl cation intermediate, and
finally (3) a hydrogenation of 3-AP to 1,4-PD. In our conditions,
the Piancatelli rearrangement of FA was favored by the
presence of weak acid sites which are provided by the
positively charged Ru species and the water-dissolved
9
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1
1
0.
1.
2
pressurized CO . Importantly, by lowering the temperature of
1
the reaction to 60 °C, it was even possible to selectively stop
the reaction at the 3-AP product, another valuable chemical. It
Y. Nakagawa, M. Tamura and K. Tomishige, Catalysis
Surveys from Asia, 2015, 19, 249-256.
is noteworthy that a further drop of the temperature to 40 °C 12.
may also be a selective mean to synthesize furfuryl alcohol,
highlighting that the selectivity of this reaction can be easily
T. Mizugaki, T. Yamakawa, Y. Nagatsu, Z. Maeno, T.
Mitsudome, K. Jitsukawa and K. Kaneda, ACS Sus. Chem.
Eng., 2014, 2, 2243-2247.
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1
1
1
1
1
1
1
3.
4.
5.
6.
7.
8.
9.
tuned. To the best of our knowledge, this work constitutes an
important advance in the field by opening a one-pot and
selective access to 1,4-PD (or 3-AP) from furfural, thus
definitely increasing the attractiveness of the furfural platform
for the supply of bio-based PD.
Conflicts of interest
S. Koso, H. Watanabe, K. Okumura, Y. Nakagawa and K.
Tomishige, Appl. Catal. B, 2012, 111–112, 27-37.
T. Lei, Z. Chi and L. Jian, J. Chem. Pharm. Res., 2013, 5,
There are no conflicts to declare.
3
96-401.
L. Corbel-Demailly, B.-K. Ly, D.-P. Minh, B. Tapin, C.
Especel, F. Epron, A. Cabiac, E. Guillon, M. Besson and C.
Pinel, ChemSusChem, 2013, 6, 2388-2395.
Acknowledgements
This work was supported by National Natural Science Founda-
tion of China (21606227, 21690080-21690084, 21673228, 20.
1776270), Strategic Priority Research Program of the Chinese
T. Mizugaki, Y. Nagatsu, K. Togo, Z. Maeno, T. Mitsudome,
K. Jitsukawa and K. Kaneda, Green Chem., 2015, 17, 5136-
2
5
139.
Academy of Sciences (XDB17020100), National Key Projects for
Fundamental Re-search and Development of China
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M. Li, G. Li, N. Li, A. Wang, W. Dong, X. Wang and Y. Cong,
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(2016YFA0202801). Department of science and technology of
Liaoning province (2015020086-101). The synchrotron
radiation experiment was performed at the 1W1B beamline of
the Beijing Synchrotron Radiation Facility (BSRF) operated at
2
00 mA and 2.2 GeV, and the BL08B2 of SPring-8 with the
approval of Japan Synchrotron Radiation Research Institute
Proposal No. 2017A3302).
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