An In-Situ Self-regeneration Catalyst for the Production of Renewable Penta-1,3-diene

Article abstract of DOI:10.1002/chem.202100613

Catalyst deactivation is a problem of great concern for many heterogeneous reactions. Here, an urchin-like LaPO₄ catalyst was easily developed for pentane-2,3-diol dehydration; it has an impressive ability to restore the activity in situ by itself during the reaction, accounting for its high stability. This facilitates the efficient production of renewable penta-1,3-diene from pentane-2,3-dione via a novel approach, where penta-2,3-diol was obtained as an intermediate in 95 % yield under mild conditions.

Full text of DOI:10.1002/chem.202100613

Accepted Article
Accepted Article
Title: An In-situ Self-regeneration Catalyst for the Production of
Renewable 1,3-pentadiene
Authors: Ruilin Feng, Yanlong Qi, Shijun Liu, Long Cui, Quanquan Dai,
and Chenxi Bai
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.202100613
Link to VoR: https://doi.org/10.1002/chem.202100613
01/2020

10.1002/chem.202100613
Chemistry - A European Journal
COMMUNICATION
An In-situ Self-regeneration Catalyst for the Production of
Renewable 1,3-pentadiene
Ruilin Feng,[a,b] Yanlong Qi,*[a] Shijun Liu,[a,b] Long Cui, [a] Quanquan Dai [a] and Chenxi Bai*[a,b]
[a]
R. Feng, Y. Qi, S. Liu, L. Cui, Q. Dai, Prof. C. Bai
Key Laboratory of High-Performance Synthetic Rubber and Its Composite Materials
Changchun Institute of Applied Chemistry, Chinese Academy of Sciences.
Renmin Road, Changchun 130022, China.
E-mail: ylqi@ciac.ac.cn; baicx@ciac.ac.cn
[b]
R. Feng, S. Liu, Prof. C. Bai
Applied Chemistry
University of Science and Technology of China
Jinzhai Road, Hefei 230026, China.
Supporting information for this article is given via a link at the end of the document
Abstract: Catalyst deactivation is a problem of great concern for
many heterogeneous reactions. Here, an urchin-like LaPO4 catalyst
was facile developed for 2,3-pentanediol dehydration, it features an
impressive ability to restore the activity in situ by itself during the
reaction, accounting for its high stability. This facilitates the efficient
production of renewable 1,3-pentadiene from 2,3-pentanedione via a
novel approach, where 2,3-pentanediol was obtained as an
intermediate in 95% yield under mild conditions.
1,3-pentadiene with a yield of ~51%. Formic acid was
highlighted in this route, it served as both DODH reagent
and esterification reagent. Whereas, formic acid also gave
rise to the formation of 1,4-anhydroxylitol and some
unidentified compounds through the dehydration of xylitol,
which consequently afforded a considerable amount of a
dark brown liquid.
This contribution explores an alternative approach to
produce 1,3-pentadiene from the renewable feedstock by
building a platform, where a C5 diol was synthesized as an
intermediate. The great success in the catalytic conversion
of biomass-derived C4 diols to butadiene has been
achieved.[7] Recently, our group reported an alternative
approach for isoprene production under mild conditions, in
which a nonlinear C5 1,3-diol was involved.[8] Therefore, it
is expected to develop efficiently catalytic processes to
produce 1,3-pentadiene from a renewable feedstock by
employing a C5 diol as the intermediate. This will facilitate
the development of a more versatile synthetic toolbox for
the conjugated diene production.
Catalyst deactivation is a problem of great concern for
many reactions.[1] And the loss of active sites is irreversible
during the reactions. Consequently, the regeneration of
deactivation catalysts must be passively performed after the
reaction. However, the regeneration of spent catalysts
always results in partly irreversible deactivation of the active
sites.[2] Therefore, the exploration in developing a catalyst
having the ability to restore the activity in situ by itself is
attractive and rewarding.
The increasing concerns about the environment and
energy problems greatly stimulate the development of
catalytic processes to produce valued chemicals from
renewable lignocellulose in the last few years. 1,3-
Pentadiene is an important building block for petroleum
resin, hot glue, curing agent and adhesive. Currently, 1,3-
pentadiene is mainly produced by extracting C5 fraction
from naphtha steam cracking. Concerning the sustainability,
only two catalytic routes for 1,3-pentadiene production have
been reported, where biomass-derived furfural and xylitol
were respectively used as substrates. (1) Furfural was
transformed to 1,3-pentadiene through hydrogenolysis,
hydrogenation and dehydration reaction in sequence, in
which methyl furan and methyl tetrahydrofuran formed as
intermediates.[3] This approach affords a low yield of 1,3-
pentadiene (~30%) because of the presence of multiple
competing side reactions. Based on this, some works took
methyl tetrahydrofuran as substitute for furfural to directly
produce 1,3-pentadiene. And a significant progress has
been achieved.[4] Recently, a ~86% yield of 1,3-pentadiene
was obtained over a borosilicate catalyst, using methyl
tetrahydrofuran as feedstock.[5] Nevertheless, it still remains
a challenge for this route to obtain a high overall carbon
yield. (2) Sun et al.[6] reported a two-step approach: xylitol
was converted to 1-formate-2,4-pentadien-1-ol via
deoxydehydration (DODH) in the presence of formic acid,
followed by the deoxygenation over Pd/C catalyst to provide
Notably, the aforementioned work also suggests that
the positions of hydroxyl groups in the diols play a crucial
role in the reaction pathway. Whereas, the catalytic
transformation of biomass-derived C5 compounds (e.g.,
furfural, levulinic acid) to C5 diols mainly affords 1,4-diol,
1,5-diol and 1,2-diol.[9] And the conversion of these diols to
1,3-pentadiene always displays a low efficiency, typically,
with the appearance of large amount of cycle ethers
because of their thermodynamic favourability. These
stimulate us to search an alternative candidate for C5 diol
production, followed by dehydration to 1,3-pentadiene. 2,3-
Pentanedione is a bio-based chemical derived from lactic
acid. Besides, 2,3-pentanedione is industrially produced by
extracting dairy waste.[10] Currently, 2,3-pentanedione is
mainly used as a flavoring agent, and also employed to
produce renewable bisphenols which serve as plasticizers
having promising properties.[11] In the present work, 2,3-
pentanedione was employed as feedstock to develop an
alternative approach for 1,3-pentadiene production
(Scheme 1). 2,3-Pentanedione was first converted to an
intermediate of 2,3-pentadiol via the hydrogenation over
Pt/Ce/Al2O3 catalyst. The structure of 2,3-pentadiol was
identified by GCMS and NMR (Supporting Information). The
presence of ceria on the catalyst resulted in a well
dispersion of Pt particles, and enhanced the catalytic
1
This article is protected by copyright. All rights reserved.

10.1002/chem.202100613
Chemistry - A European Journal
COMMUNICATION
performance by activating H2 and decreasing the reaction
activation energy. These allowed the hydrogenation
reaction over Pt/Ce/Al2O3 giving a yield of 2,3-pentadiol as
high as 95% (at 98% conversion), much higher than that
over Pt/Al2O3 (Table S1).
narrow distribution of the weak acid sites while a wide
distribution of the moderate-strength acid sites. Besides,
the infrared spectra of LaPO4 arising from pyridine
adsorption (Py-IR) was shown in Figure 1(d), the
observation of the characteristic peaks suggested that
LaPO4 catalyst has both Brønsted (B) and Lewis (L) acid
sites.
Scheme 1. An alternative route to produce 1,3-pentadiene.
The
as-synthesized
2,3-pentadiol
subsequently
undergone a dehydration process to 1,3-pentadiene on a
fixed bed reactor in the presence of LaPO4 catalyst. LaPO4
as one of rare earth orthophosphates features the weak
and moderate acid sites and a few weak basic sites. Millet
et al. clarified that the rare earth orthophosphate catalysts
presented the structure-sensitivity property for butanediol
dehydration, they suggested that the side facets of the
nanorod catalyst were preferentially for the dehydration of
2,3-butanediol to butadiene, while the tips accounted for the
side reactions.[12] It has been recognized that the
morphology and crystal structure of LaPO4 depend on its
preparation method.[13] In this work, an urchin-like LaPO4
catalyst was prepared, as shown in Figure 1(a). Scanning
electron microscope (SEM) image disclosed LaPO4 having
an ordered nanostructure with a well-defined shape. The
one-dimensional nanorods, with <60 nm in diameter
and >120 nm in length, closely contacted each other and
built on the catalyst bulk to form an urchin-like material with
three dimensions. A good uniformity and a narrow size
distribution of nanorods were illustrated. High-resolution
transmission electron microscope (HTEM) image displayed
well-resolved lattice fringes with the interplanar spacing of
3.1 Å and 2.9 Å, corresponding to the (102) and (200)
planes of LaPO4, respectively. An angle of 29° between
(102) and (200) planes was observed. Energy dispersive
spectrometer (EDS) analysis with a randomly selected area
suggested a uniform distribution of La and P. The X-ray
diffraction (XRD) pattern was presented in Figure 1(b),
revealing that the as-prepared LaPO4 was comprised of the
monoclinic phases (JCPDS 32-0493). In Raman spectra,
the bands in the 900~1100 cm-1 region were associated
with P-O stretching modes. The peaks at approx. 1058 and
1079 cm-1 corresponded to asymmetric stretching of P-O in
PO4. The peak at 967~985 cm-1 can be attributed to the
stretching vibration of the P-O bond in the adsorbed
(HnPO4)-3+n. The bands at 396, 414, 467 cm-1 and the bands
at 540, 573, 621 cm-1 derived from O-P-O E-bending and
F2-bending, respectively. The peak at approx. 274 cm-1
related to the vibration of (HnPO4)-3+n. Figure 1(c) displays
the profile of temperature-programmed desorption of NH3
(NH3-TPD). A large peak at approx. 150°C and a broad
shoulder peak at approx. 250°C with considerable overlap
were observed. These two peaks can be respectively
assigned to the weak acid sites (the peak at lower
temperature) and moderate-strength acid sites (the peak at
higher temperature). Notably, the fitting curves implied a
Figure 1. Characteristics of urchin-like LaPO4: (a) SEM-EDS analysis with
HTEM image inner, (b) XRD pattern and Raman spectra, (c) NH3-TPD profile
with fitted curves, and (d) Py-IR curve of LaPO4.
Urchin-like LaPO4 displayed a high stability for the
dehydration of 2,3-pentadiol to 1,3-pentadiene, exhibiting
54~59% yield of 1,3-pentadiene at complete conversion
during 13 h runs (Figure 2). The side reactions mainly
afforded 2-methylbutyraldehyde (2-MBA), 2-pentanone (2-
PN) and 3-pentanone (3-PN), which were similar with the
2,3-butanediol dehydration.[14] The elimination of one
hydroxyl group of ortho-diols provided an intermediate
which was subsequently converted to conjugated dienes,
aldehydes and ketones through dehydration reaction,
methyl rearrangement and hydrogen rearrangement,
respectively.[15] The facile occurrence of the methyl
rearrangement and hydrogen rearrangement leaves a great
challenge for the dehydration of ortho-diols to conjugated
dienes. On the other hand, the dehydration of 2,3-pentadiol
quite differs from 2,3-butanediol dehydration, because of
the asymmetric electron environment of two hydroxyl
groups in 2,3-pentadiol. Thus, the 2,3-pentadiol dehydration
gives more byproducts. Fortunately, the as-prepared LaPO4
afforded a 1,3-pentadiene yield as high as 59%, which was
higher than that of 2,3-butanediol dehydration to butadiene
over reported nanorod LaPO4 catalyst. This may benefit
from the urchin-like morphology with ordered nanostructure,
which gave rise to a characteristic acid distribution.
2
This article is protected by copyright. All rights reserved.

10.1002/chem.202100613
Chemistry - A European Journal
COMMUNICATION
100
80
60
40
20
0
100
80
60
40
20
0
1
2 3 4 5 6 7 8 9 10 11 12 13
Figure 2. Catalytic results versus time on stream. 1,3-PD (1,3-pentadiene), 2-
MBA (2-methylbutyraldehyde), 2-PN (2-pentanone), 3-PN (3-pentanone).
Figure 3. Impressive observation of in-situ restoring activity of urchin-like
LaPO4 for 1,3-pentadiene production: (a) pyridine (Py) and (b) 2,6-
ditertbutylpyridine (DTBPy) were employed for the reaction test, where a feed
of 2,3-pentadiol (PeDO, black square), a feed of 2,3-pentadiol containing Py or
DTBPy (red circle), and a feed of Py or DTBPy prior to 2,3-pentadiol (blue
rhombus) were used, respectively.
Since the outstanding reactivity of the conjugated
double bonds, the on-purpose production of conjugated
dienes through the dehydration reaction is significantly
accompanied by the formation of the carbon deposition.
Thus, the catalyst stability is of outmost important. The high
stability of rare earth orthophosphates was always
attributed to their carbon-resistant properties because of the
absence of strong acid sites in this kind of catalysts.[12, 16]
Accordingly, the loss of acid sites will lead to an irreversible
decrease in catalyst activity during the reaction. Herein,
pyridine (Py) and 2,6-diertbutylpyridine (DTBPy) were
employed to poison the acid sites on urchin-like LaPO4
The increase in 1,3-pentadiene yields with time on
stream implied that the loss of acid sites can be restored
during the dehydration reaction. To directly clarify the
changes in the urchin-like LaPO4, NH3-TPD coupled with
mass spectrometry was further conducted, the results were
presented in Figure 4. Pyridine was used to treat LaPO4 at
the reaction conditions, followed by 2,3-pentadiol
dehydration. After 3 h runs, the spent LaPO4 was recovered
for NH3-TPD analysis (red circle), and the pyridine treated
LaPO4 without the dehydration was also applied for NH3-
TPD analysis as comparison (black square). Accordingly,
compared to fresh LaPO4, the treated catalyst having much
lower acid sites derived from the adsorption of pyridine,
(Figure 3). Impressively,
a distinct increase in 1,3-
pentadiene yield was unexpectedly observed with time on
stream, which suggested that urchin-like LaPO4 had an
ability to restore the activity in situ. Pyridine can react with
Lewis and Brønsted acid sites, while DTBPy selectively
poisons Brønsted acid sites because of steric hindrance.
Figure 3(a) displays the comparison of catalytic results with
or without pyridine in the dehydration reaction. Without
pyridine in the reaction system, the dehydration of 2,3-
pentadiol over urchin-like LaPO4 provided a well stable 1,3-
pentadiene yield during 3 h on stream (black square). When
pyridine was fed to the reactor together with 2,3-pentadiol,
a much lower yield (< 38%) of 1,3-pentadiene at 1 h on
stream was observed (red circle). And a similar result was
obtained when pyridine was fed to the reactor prior to 2,3-
pentadiol (blue rhombus). Then the yields increased with
time on stream, and reached ~59.6% which were close to
that obtained in the absence of pyridine. On the other hand,
when DTBPy was fed together with 2,3-pentadiol, the
dehydration results (red circle, Figure 3b) were close to that
obtained without DTBPy. Whereas, similar changes in
catalytic results, compared with that obtained in the
presence of pyridine, were found in the case of feeding
DTBPy to the reactor prior to 2,3-pentadiol (blue rhombus,
Figure 3b). This was due to that larger steric hindrance of
DTBPy hindered its adsorption on the catalyst surface
compared with 2,3-pentadiol.
consequently, provided
a
low yield. Whereas, the
unambiguous changes appeared in LaPO4 surface during
the reaction, which leaded to an increase in acid sites for
the spent LaPO4 compared with treated LaPO4. Notably,
the apparent peak at approx. 450°C in NH3-TPD curve (red
circle) was assigned to ammonia desorption, confirmed by
mass spectrometry. The appearance of this peak
suggested the formation of strong acid sites on LaPO4
during the 2,3-pentadiol dehydration.
In addition, Py-IR analysis clarified that these strong
acid sites mainly consisted of Lewis acid, because that the
pyridine-poisoning LaPO4 after use had larger number of
acid sites (special for Lewis acid sites), compared to the
spent LaPO4 without treatment by pyridine (FigureS7 and
Table S2). Besides, DTBPy treated LaPO4 displayed similar
changes in NH3-TPD curves (Figure S8). Consequently, it
was deduced that the dehydration definitely influenced the
LaPO4 acidity (including strength, amount), where either the
deactivation sites were activated in situ, or the loss of active
sites was accompanied by the formation of new active sites.
The reconstruction of active sites may benefit from that
formed water adsorbs on moderate-strength acid sites
without dissociation because of the absence of strong acid
in LaPO4. In addition, the comparison of XRD pattern
between spent LaPO4 and fresh LaPO4 identifies no
3
This article is protected by copyright. All rights reserved.

10.1002/chem.202100613
Chemistry - A European Journal
COMMUNICATION
[4] a) O. A. Abdelrahman, D. S. Park, K. P. Vinter, C. S. Spanjers, L.
Ren, H. J. Cho, D. G. Vlachos, W. Fan, M. Tsapatsis, P. J.
Dauenhauer, ACS Sustain. Chem. Eng. 2017, 5, 3732-3736; b) M.
D. Kumbhalkar, J. S. Buchanan, G. W. Huber, J. A. Dumesic, ACS
Catal. 2017, 7, 5248-5256.
changes in the bulk structure of the catalyst (Figure S9).
These suggest the changes in LaPO4 were reversible,
without destroying catalyst structure. Therefore, the ability
to restore activity in situ may factually account for the high
stability of rare earth orthophosphates.
[5] G. Kumar, D. Liu, D. Xu, L. Ren, M. Tsapatsis, P. J. Dauenhauer,
Green Chem. 2020, 22, 4147-4160.
[6] R. Sun, M. Zheng, X. Li, J. Pang, A. Wang, X. Wang, T. Zhang,
Green Chem. 2017, 19, 638-642.
[7] a) E. V. Makshina, M. Dusselier, W. Janssens, J. Degrève, P. A.
Jacobs, B. F. Sels, Chem. Soc. Rev. 2014, 43, 7917-7953; b) H.
Duan, Y. Yamada, S. Sato, Chem. Lett. 2016, 45, 1036-1047; c) D.
Sun, Y. Li, C. Yang, Y. Su, Y. Yamada, S. Sato, Fuel Process.
Technol. 2020, 197, 106193.
[8] a) Y. Qi, S. Liu, L. Cui, Q. Dai, C. Bai, Appl. Catal. A, 2020, 603,
117745; b) Y. Qi, S. Liu, L. Cui, Q. Dai, J. He, W. Dong, C. Bai, ACS
Sustain. Chem. Eng. 2020, 8, 10323-10329.
[9] a) F. M. A. Geilen, B. Engendahl, A. Harwardt, W. Marquardt, J.
Klankermayer, W. Leitner, Angew. Chem. Int. Ed. 2010, 49, 5510-
5514; Angew. Chem. 2010, 122, 5642-5646; b) Rodiansono, M.
Figure 4. NH3-TPD curves: pyridine treated LaPO4 prior to dehydration (black
square) and after dehydration (red circle)
Dewi Astuti, T. Hara, N. Ichikuni, S. Shimazu, Green Chem. 2019
,
21, 2307-2315; c) F. Liu, Q. Liu, J. Xu, L. Li, Y.-T. Cui, R. Lang, L. Li,
Y. Su, S. Miao, H. Sun, B. Qiao, A. Wang, F. Jérôme, T. Zhang,
Green Chem. 2018, 20, 1770-1776.
In summary, an alternative approach for the production
of renewable 1,3-pentadiene from 2,3-pentanedione was
[10] a) M. Dusselier, P. Van Wouwe, A. Dewaele, E. Makshina, B. F.
Sels, Energ.Environ. Sci. 2013, 6, 1415-1442; b) F. Liguori, C.
Moreno-Marrodan, P. Barbaro, Chem. Soc. Rev. 2020, 49, 6329-
6363.
reported, where
a
cascade process combining the
hydrogenation and dehydration reaction was involved.
Importantly, an urchin-like LaPO4 was readily developed for
the dehydration reaction. NH3-TPD analysis and pyridine
adsorption experiment demonstrate that urchin-like LaPO4
can restore the active sites during the reaction, displaying
an in-situ self-regeneration performance. This may factually
account for the high stability of rare earth orthophosphates.
Consequently, urchin-like LaPO4 provided a 59% yield of
1,3-pentadiene. We believe that the present findings will
provide a new strategy for the development of the efficient
catalysts with long life. Further mechanistic studies on the
self-regeneration performance of LaPO4 are underway.
[11] a) X. Li, Y. Zhang, Z. Chen, P. Cao, W. Zou, C. Tang, L. Dong, Y.
Wang, Ind. Eng. Chem. Res. 2017, 56, 14437-14446; b) W.
Schutyser, S.-F. Koelewijn, M. Dusselier, S. Van de Vyver, J.
Thomas, F. Yu, M. J. Carbone, M. Smet, P. Van Puyvelde, W.
Dehaen, B. F. Sels, Green Chem. 2014, 16, 1999-2007.
[12]M. Huchede, T. T. N. Nguyen, L. Cardenas, M. Aouine, K. Jaillardon,
J.-M. M. Millet, J. Phys. Chem. B 2020, 124, 2060-2069.
[13] S. Lucas, E. Champion, D. Bregiroux, D. Bernache-Assollant, F.
Audubert, J. Solid State Chem. 2004, 177, 1302-1311.
[14] a) N. T. T. Nguyen, F. Matei-Rutkovska, M. Huchede, K. Jaillardon,
G. Qingyi, C. Michel, J. M. M. Millet, Catal. Today 2019, 323, 62-68;
b) X. Liu, V. Fabos, S. Taylor, D. W. Knight, K. Whiston, G. J.
Hutchings, Chem-Eur. J. 2016, 22, 12290-12294.
Acknowledgements
[15] a) H. Duan, Y. Yamada, S. Kubo, S. Sato, Appl. Catal. A, 2017, 530,
66-74; b) A. G. Thome, N. Ayral, H. Toufar, T. Klüner, F. Roessner,
Catal. Lett. 2017, 147, 1271-1277.
Financial support from National Natural Science Foundation
of China (22001245, 51873203), Key Projects of Jilin Province
Science and Technology Development Plan (20200401042GX,
20200401041GX), Special Fund Supported Project for High-tech
Industrialization of Science and Technology Cooperation
between Jilin Province and the Chinese Academy of Sciences
(2019SYHZ0003).
[16] T. T. N. Nguyen, V. Ruaux, L. Massin, C. Lorentz, P. Afanasiev, F.
Maugé, V. Bellière-Baca, P. Rey, J. M. M. Millet, Appl. Catal. B,
2015, 166-167, 432-444.
Keywords: Catalyst regeneration • Biobased Chemicals •
Pentadiene production • Sustainability
[1] a) I. Ivanova, V. L. Sushkevich, Y. G. Kolyagin, V. V. Ordomsky,
Angew. Chem. Int. Ed. 2013, 52, 12961-12964; Angew. Chem.
2013, 125, 13199-13202; b) W. A. Groten, B. W. Wojciechowski, B.
K. Hunter, J. Catal. 1990, 125, 311-324.
[2] a) P. Forzatti, L. Lietti, Catal. Today 1999, 52, 165-181; b) C. H.
Bartholomew, Appl. Catal. A, 2001, 212, 17-60.
[3] L. W. Burnette, Rubber Chem. Technol. 1945, 18, 284-285.
4
This article is protected by copyright. All rights reserved.

10.1002/chem.202100613
Chemistry - A European Journal
COMMUNICATION
Entry for the Table of Contents
An alternative approach for the efficient production of renewable 1,3-pentadiene was reported: bio-based 2,3-pentanedione
hydrogenation by Pt/Ce/Al2O3 catalyst to 2,3-pentadiol giving a selectivity of 95% at 98% conversion under mild conditions, followed
by dehydration reaction over an urchin-like LaPO4 catalyst affording 1,3-pentadiene in yield of 59%. The urchin-like LaPO4 displayed
self-regeneration performance during the dehydration reaction, which was due to its ability to restore the active sites in situ by itself.
5
This article is protected by copyright. All rights reserved.