An Ionic Liquid on a Porous Organic Framework Support: A Recyclable Catalyst for the Knoevenagel Condensation in an Aqueous System

Article abstract of DOI:10.1002/cplu.202000093

Porous aromatic frameworks (PAFs) that feature a high density of phenyl rings in their robust frameworks are attractive platforms for catalysis because of their extremely high stability, high surface area, and adjustable pore size. In this paper, two PAF-

Full text of DOI:10.1002/cplu.202000093

A Multidisciplinary Journal Centering on Chemistry
Accepted Article
Title: An Ionic Liquid on a Porous Organic Framework Support: A
Recyclable Catalyst for the Knoevenagel Condensation in an
Aqueous System
Authors: Peng Chen, Lei Zhang, Jin-Shi Sun, En-Kai Xiao, Xian-Tao
Wu, and Guangshan Zhu
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: ChemPlusChem 10.1002/cplu.202000093
Link to VoR: https://doi.org/10.1002/cplu.202000093
0
1/2020

ChemPlusChem
10.1002/cplu.202000093
COMMUNICATION
An Ionic Liquid on a Porous Organic Framework Support: A
Recyclable Catalyst for the Knoevenagel Condensation in an
Aqueous System
Peng Chen, Lei Zhang, Jin-Shi Sun, [c] En-Kai Xiao, [a] Xian-Tao Wu, [a] and Guangshan Zhu*[b,c]
[
a]
[c]
Abstract: Porous aromatic frameworks (PAFs) featured by the high
density of phenyl rings in their robust frameworks are attractive
platforms for catalysis because of their extremely high stability, high
surface area and adjustable pore size. In this paper, two novel PAF-
supported ionic liquids were constructed by introducing ionic liquid
units onto the framework of a PAF material named PAF-111 using a
series of stepwise post-synthetic modifications. The basic PAF-
supported ionic liquid with hydroxyl anion exhibited high catalytic
activity, high stability and could undergo at least 10 cycles without
any activity loss when catalyzing Knoevenagel condensation
reaction under aqueous conditions. It is expected that our study will
further promote the development of designing and applying
functional PAF materials for catalysis in aqueous system.
catalytic active sites are more exposed in the pores constructed
by the robust frameworks of PAFs，PAF materials have been
proved by our group to have distinctive advantages as platforms
for organocatalysis[9] and organometallic catalysis[10]. However,
most of the reported PAF-based catalysts were used in organic
solvents. Considering that PAF materials have highly stable
absolute organic frameworks, the systematic investigation of the
PAF-based catalysts in aqueous system is very attractive for the
reserchers in this field.
In this paper, Ionic liquid catalytic sites will be introduced into
the pores of PAF materials and the performence of the resultant
catalysts in aqueous system will be studied. Ionic liquids have
been found to have many advantages in the area of green
[
11]
chemistry.
Supported ionic liquid, which is highly
In recent years, a tremendous development has been seen in
the field of porous organic materials which were built entirely
from organic building blocks via strong covalent bonds.[1]
Covalent organic frameworks (COFs) and porous organic
polymers (POPs) are two representative types of porous organic
materials. Generally, COFs are all prepared by reversible
reactions, therefore COFs usually have orderd structures but the
resultantly formed covalent bonds such as boron-oxygen bonds
or imine bonds could reduce the stability of COFs under certain
conditions and can interfere with some aplications. By contrast,
POPs constructed by very stable covalent bonds have high
stability but usually with flexible structure. In the last decades,
advantageous because of the ease of separation, is necessary
in chemical industry. Considering the need of easy accessibility
to the catalytic sites, PAFs with hierarchically porous structures
are one of the best candidates as the platform for immobilizing
ionic liquid.
Taking into account the above discussion, the hierarchically
porous material PAF-111, which was synthesized in our
[
12]
previous literature, was selected as the supported material. In
order to introduce the ionic liquid site, a series of stepwise post-
synthetic modifications was applied in our strategy (Scheme 1).
First, a chloromethyl group was attached to the framework of
PAF-111 as an electrophilic site, through the chloromethylation
our group has developed
a series of porous aromatic
reaction using paraformaldehyde in
affording PAF-111-CH Cl. Then through the newly introduced
electrophilic chloromethyl site, the ionic liquid functional group
could be easily introduced onto the framework by the S
a mixed acid solution,
frameworks (PAFs) which is a new type of porous organic
material.[1e, 2] Because PAFs are constructed by high density of
rigid aromatic building blocks, they usually have robust
frameworks and perfect stability, which could combine the
exceptional features of COFs and POPs.[2e, 3] Since the seminal
work of PAF-1[4] reported by our group, PAFs have been used
2
N
2
substitution reaction using N-Methylimidazole as nucleophilic
reagent, and the obtained material was named PAF-111-IL(Cl).
for diverse applications such as adsorption,[
3,
5]
separation,
[6]
sensing[7] and heterogeneous catalysis[8]. Due to that the
[
[
a]
b]
Dr. P. Chen, E.-K. Xiao, X.-T. Wu
School of Materials Science and Chemical Engineering
Ningbo University
Ningbo 315211, China.
Prof. Dr. G. Zhu
Key Laboratory of Polyoxometalate Science of Ministry of
Education, Faculty of Chemistry
Northeast Normal University
Changchun 130024, China
E-mail: zhugs@nenu.edu.cn
[
c]
L. Zhang, J.-S. Sun, Prof. Dr. G. Zhu
State Key Laboratory of Inorganic Synthesis and Preparative
Chemistry, College of Chemistry,
Jilin University
Changchun 130012, China.
Supporting information for this article is given via a link at the end of
the document.
Scheme 1. Synthetic route for PAF-111-IL(Cl) and PAF-111-IL(OH).
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.202000093
COMMUNICATION
Figure 2. Nitrogen adsorption (solid symbols)–desorption (open symbols)
2
isotherms measured at 77 K for PAF-111, PAF-111-CH Cl, PAF-111-IL(Cl)
and PAF-111-IL(OH).
Figure 1. FT-IR spectra of PAF-111, PAF-111-CH
PAF-111-IL(OH).
2
Cl, PAF-111-IL(Cl) and
Then through a simple anion exchange reaction, the chloride
-
anion could be easily transformed to hydroxyl anion (OH ), and
the designed immobilized basic ionic liquid PAF-111-IL(OH)
could be obtained.
After obtaining the PAF materials in Scheme 1, Fourier
transform infrared (FT-IR) spectra were first conducted to verify
if the strategy successfully led to the desired catalyst. As shown
in Figure 1, compared with PAF-111, in the FT-IR spectrum of
-
1
PAF-111-CH
2
Cl, the newly appeared peak at 1242 cm and the
newly appeared peaks in the region of 2830-2980 cm- could be
respectively ascribed to bending vibration and stretching
vibration of saturated C−H bonds linked to the chlorine atom.
These new peaks indicated the successful introduction of
chloromethyl group into the PAF material. Compared with PAF-
1
1
1
11-CH
2
Cl, in the FT-IR spectra of PAF-111-IL(Cl) and PAF-
Figure 3. TGA plots of PAF-111, PAF-111-CH
111-IL(OH).
2
Cl, PAF-111-IL(Cl) and PAF-
11-IL(OH), the similar peaks in the region of 2830-2980 cm-1
indicated the existence of saturated C−H bonds and the new
band at 1672 cm-1 could be assigned to C=N bonds of the
imidazole ring. In addtion, the strongly enhanced broad band at
Then the thermogravimetric analysis (TGA) was used to test
the thermal stability of the obtained PAF materials. As shown in
Figure 3, the TGA curves of PAF-111 showed no obvious weight
3
420 cm−1 in the FT-IR spectrum of PAF-111-IL(OH) could be
assigned to stretching vibration of hydroxyl group. These results
agree well with the designed structures of PAF-111-IL(Cl) and
PAF-111-IL(OH), clearly indicating that the ionic liquid was
successfully immobilized into the PAF material.
oC, suggesting its high thermal stability.
loss below 450
Compared with PAF-111, PAF-111-CH2
weight loss starting at 370
Cl showed an obvious
oC, which might be ascribed to the
The porosities of the obtained materials were demonstrated
by nitrogen adsorption–desorption isotherms, as shown in
decomposition of chloromethyl group on the framework. In the
case of PAF-111-IL(Cl) and PAF-111-IL(OH), there was a slow
Figure 2. The isotherms of PAF-111, PAF-111-CH
2
Cl, PAF-111-
o
loss of mass below 370 C, which might be due to the gradual
IL(Cl) and PAF-111-IL(OH) in Figure 2 all showed a rapid
uptake at low relative pressure, indicating the existence of
micropores in the above PAF materials. The Brunauer–Emmett–
loss of some guest molecules in the pores of the PAF material.
o
The loss of mass below 370
C for PAF-111-IL(OH) was more
obvious than that for PAF-111-IL(Cl), which indicated that in
PAF-111-IL(OH) there were stronger interaction forces (such as
intermolecular hydrogen bonding) between the ionic liquid units
and the guest molecules. In addition, PAF-111-IL(Cl) and PAF-
111-IL(OH) both showed a slow weight loss between 370-480
Teller (BET) surface areas for PAF-111, PAF-111-CH
2
Cl, PAF-
2
-1
1
11-IL(Cl) and PAF-111-IL(OH) were 857 m g-1, 749 m2 g ,
2
-1
2
-1
7
02 m g and 666 m g respectively. The changes of the BET
surface areas for the above PAF materials matched well with the
sizes of the corresponding functional groups in them.
o
C, which might be attributed to the decomposition of the ionic
liquid units hung onto the framework. For all the above PAF
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.202000093
COMMUNICATION
Table 1. The control experiments for PAF-111-IL(OH) catalysed Knoevenagel
condensation reaction.
Table 2. PAF-111-IL(OH) catalysed Knoevenagel condensation reaction.[a]
[
a]
entry
catalyst (catalyst loading)
Solvent
CH Cl
Time
Yield[b]
carbonyl
compound
entry
Product
Time
yieldb
1
PAF-111-IL(OH) (1.4 mol%)
2
2
1h
53%
2
3
4
5
6
PAF-111-IL(OH) (1.4 mol%)
PAF-111-IL(OH) (1.4 mol%)
PAF-111-IL(OH) (2.8 mol%)
PAF-111-IL(Cl) (1.4 mol%)
No catalyst
MeOH
1h
62%
97%
97%
49%
8%
1
40min
97%
H
H
H
H
H
2
2
2
2
2
O
O
O
O
O
40min
25min
40min
40min
40min
40min
2
3
2.5h
2h
96%
96%
7
PAF-111-CH
2
Cl (10 mg)
9%
8[c]
The supernatant liquid of the
8%
H
2
O suspension of PAF-111-
IL(OH)
[
a] Reaction conditions (unless other noted):
A
mixture of 0.80 mmol
O was
4
5
2.5h
93%
95%
benzaldehyde, 0.80 mmol malononitrile and the catalyst in 4 mL of H
stirred at room temperature for the indicated time. The catalyst loading was
determined based on the elemental analysis: 2.80 wt% of nitrogen for PAF-
1
wt% of nitrogen for PAF-111-IL(OH) suggested 1.1 mmol g of ionic liquid
unit in the material. [b] Isolated yield. [c] 10 mg PAF-111-IL(OH) was
2
11-IL(Cl) suggested 1.0 mmol g-1 of ionic liquid unit in the material and 3.08
30min
-1
2
immersed in 4 mL of H O for 40min at room temperature. After filtration, to the
liquid was added 0.80 mmol benzaldehyde and 0.80 mmol malononitrile, then
the resulted mixture was stirred at room temperature for 40 min.
[a] Reaction condition: A mixture of 0.80 mmol carbonyl compound 1a-5a,
0.80 mmol malononitrile and 10 mg PAF-111-IL(OH) (1.1 mmol g-1 of ionic
liquid unit in the material which was calculated from the data of elemental
analysis) in 4 mL of H
2
O was stirred at room temperature for the indicated
time. [b] Isolated yield.
materials, the obvious decomposition of the frameworks could
be observed at about 480-630 oC. The above analysis
demonstrated the high thermal stability of the obtained PAF
materials including the desired immobilized catalyst.
Furthermore, PAF-111-IL(Cl) and PAF-111-IL(OH) could not be
decomposed or dissolved in almost all common organic solvents
and water, even in boiling water. It is very important that their
excellent stability in water could lay a good foundation for the
latter catalysis study in aqueous catalysis.
It was found that PAF-111-IL(Cl) also could catalyse the current
reaction, however, with a lower yield in the same conditions
(Table 1, entry 5). PAF-111-IL(Cl) showed a lower catalytic
activity than PAF-111-IL(OH) for the current reaction, which
might be due to the weaker basicity of PAF-111-IL(Cl) in
comparison with PAF-111-IL(OH). In addition, the reaction could
occur slowly in the absence of catalyst (Table 1, entry 6). Using
After the elaborate characterization of the desired PAF-111-
IL(Cl) and PAF-111-IL(OH), their catalytic properties were then
studied. Knoevenagel condensation reaction, which is a highly
effective organic C=C bond forming reaction and ofen used to
test the catalytic activities of basic catalysts, was selected as the
model reaction to investigate their catalytic performance. First,
using benzaldehyde and malononitrile as model substrates,
some control experiments were performed and the results were
listed in Table 1. As shown in entries 1-3 of Table 1, among the
PAF-111-CH
with that in the absence of catalyst, indicating that PAF-111-
CH Cl has not catalytic activity for this reaction. Results of the
above investigations suggested that PAF-111-IL(OH) is indeed
efficient catalyst for the Knoevenagel condensation reaction
under aqueous conditions. The entry 8 of Table 1 clearly
2
Cl in the reaction system gave the same result
2
2
demonstrated that the supernatant liquid of the H O suspension
of PAF-111-IL(OH) have no catalytic activity for the
Knoevenagel condensation reaction. It indicated no leakage of
catalytically active species from the PAF-111-IL(OH) catalyst
during the catalysis process and thus the current catalytic
reaction proceed via a heterogeneous process.
2 2 2 2
screened solvents (CH Cl , MeOH and H O), H O gave the best
reaction rate and yield of the current catalytic Knoevenagel
condensation reaction. In other words, PAF-111-IL(OH) as
catalyst could be used in aqueous system and gave a high
catalytic activity under these conditions. The entries 3 and 4 of
Table 1 demonstrated that increasing the catalyst loading from
Under the above optimized conditions, using a series of
carbonyl compounds and malononitrile as the reaction
substrates, the catalytic performance of PAF-111-IL(OH) was
further tested at a 1.4 mol% catalyst loading at room
1.4 mol% to 2.8 mol% could improve the reaction rate (Table 1).
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.202000093
COMMUNICATION
Table 3. The recycle test of PAF-111-IL(OH) catalysed Knoevenagel
condensation reaction.
Experimental Section
[
a]
Details of the experimental procedures are provided in the Supporting
Information.
cycle
Time
yieldb
cycle
Time
Yield[b]
Acknowledgements
1
40min
97%
6
40min
96%
2
4
40min
40min
97%
95%
8
40min
40min
95%
97%
This work was sponsored by the financial support of Zhejiang
Provincial Natural Science Foundation (ZJNSF, Grant No.
LY19B020003), National Natural Science Foundation of China
10
(
NSFC, Grant Nos. 21531003 and 21302061) and K. C. Wong
[
a] The reaction conditions and the recycle procedure could be found in
Magna Fund in Ningbo University.
the supporting information. [b] Isolated yield.
Conflict of Interest
temperature. As shown in Table 2, various aromatic aldehydes
with different substituent groups on the phenyl ring (Table 2,
entries 1-4) could all react with malononitrile and give high
isolated yields in considerably short reaction times. Besides the
above aromatic aldehydes, the cyclohexanone could also give
an excellent yield with a short reaction time (Table 2, entry 5)
under the same conditions.
The authors declare no conflict of interest.
Keywords: aqueous systems • ionic liquids • heterogeneous
catalysis
• Knoevenagel condensation • porous aromatic
frameworks
The recyclability, which is an important factor for
a
[1]
a) P. Kaur, J. T. Hupp, S. T. Nguyen, ACS Catal. 2011, 1, 819-835; b)
C. Li, Catal. Rev. 2011, 46, 419-492; c) S. Y. Ding, W. Wang, Chem.
Soc. Rev. 2013, 42, 548-568; d) A. G. Slater, A. I. Cooper, Science
heterogeneous catalyst, of PAF-111-IL(OH) was then evaluated
by subjecting PAF-111-IL(OH) to 10 cycles of the Knoevenagel
condensation reaction of benzaldehyde and malononitrile. The
experimental results were listed in Table 3. In each cycle, the
reaction was driven to react for the same time. It was found that
the catalytic activity of PAF-111-IL(OH) was very stable and
after 10 cycles PAF-111-IL(OH) showed no loss of catalytic
activity. After 10 cycles the FT-IR spectrum (Figure S6) of the
recycled PAF-111-IL(OH) was measured and showed that there
was no obvious change compared with the fresh PAF-111-
IL(OH). The porosity of the recycled catalyst was aso evaluated
by nitrogen adsorption–desorption isotherms (Figure S7). The
2015, 348, aaa8075; e) S. Das, P. Heasman, T. Ben, S. Qiu, Chem.
Rev. 2017, 117, 1515-1563.
[2]
a) A. Trewin, A. I. Cooper, Angew. Chem. Int. Ed. 2010, 49, 1533-1535;
b) T. Ben, S. Qiu, CrystEngComm 2013, 15, 17-26; c) X. Zou, H. Ren,
G. Zhu, Chem. Commun. 2013, 49, 3925-3936; d) J. M. H. Thomas, A.
Trewin, J. Phys. Chem. C 2014, 118, 19712-19722; e) C. Pei, T. Ben, S.
Qiu, Mater. Horiz. 2015, 2, 11-21; f) U. Díaz, A. Corma, Coordin. Chem.
Rev. 2016, 311, 85-124.
[
[
3]
4]
S. Demir, N. K. Brune, J. F. Van Humbeck, J. A. Mason, T. V. Plakhova,
S. Wang, G. Tian, S. G. Minasian, T. Tyliszczak, T. Yaita, T. Kobayashi,
S. N. Kalmykov, H. Shiwaku, D. K. Shuh, J. R. Long, ACS Cent. Sci.
2016, 2, 253-265.
2
BET surface area for the recycled PAF-111-IL(OH) was 520 m
T. Ben, H. Ren, S. Ma, D. Cao, J. Lan, X. Jing, W. Wang, J. Xu, F.
Deng, J. M. Simmons, S. Qiu, G. Zhu, Angew. Chem. Int. Ed. 2009, 48,
9457-9460.
-
1
g . The slight decrease of the surface area might be due to that
some reaction substrates or products were adsorbed in the
pores of the catalyst. However, the high surface area of the
recycled catalyst could demonstrate that the recycled catalyst
still had high porisity.
[5]
a) B. Li, Y. Zhang, R. Krishna, K. Yao, Y. Han, Z. Wu, D. Ma, Z. Shi, T.
Pham, B. Space, J. Liu, P. K. Thallapally, J. Liu, M. Chrzanowski, S. Ma,
J. Am. Chem. Soc. 2014, 136, 8654-8660; b) L. N. Li, H. Ren, Y. Yuan,
G. L. Yu, G. S. Zhu, J. Mater. Chem. A 2014, 2, 11091-11098; c) B. Li,
Y. Zhang, D. Ma, Z. Shi, S. Ma, Nat. Commun. 2014, 5, 5537; d) Z. Yan,
Y. Yuan, Y. Tian, D. Zhang, G. Zhu, Angew. Chem. Int. Ed. 2015, 54,
In conclusion, through post-functionalization method, ionic
liquids were introduced into the pores of PAF-111 as catalytic
sites, obtaing two PAF-supported ionic liquids named PAF-111-
IL(Cl) and PAF-111-IL(OH). PAF-111-IL(OH) exhibited high
catalytic activity for Knoevenagel condensation reaction in
aqueous system. Benefited by the outstanding stability of the
frameworks of the PAF-based catalyst, PAF-111-IL(OH) showed
excellent recyclability, that is, there was no activity loss in the
current aqueous catalysis system after at least 10 cycles. This
result demonstrates that PAF-based catalysts could perform
excellently in aqueous system. This study presents an enticing
prospect of using PAFs as an ultrastable platform to immobilize
ionic liquids and will promote the application of PAF materials for
aqueous catalysis.
1
2733-12737; e) B. Li, Y. Zhang, D. Ma, Z. Xing, T. Ma, Z. Shi, X. Ji, S.
Ma, Chem. Sci. 2016, 7, 2138-2144; f) M. Li, H. Ren, F. Sun, Y. Tian, Y.
Zhu, J. Li, X. Mu, J. Xu, F. Deng, G. Zhu, Adv. Mater. 2018, 30,
1
804169; g) Y. Yuan, Y. Yang, X. Ma, Q. Meng, L. Wang, S. Zhao, G.
Zhu, Adv. Mater. 2018, 30, 1706507; h) Y. Yang, Z. Yan, L. Wang, Q.
Meng, Y. Yuan, G. Zhu, J. Mater. Chem. A 2018, 6, 5202-5207; i) Y.
Tian, J. Song, Y. Zhu, H. Zhao, F. Muhammad, T. Ma, M. Chen, G. Zhu,
Chem. Sci. 2019, 10, 606-613.
[6]
a) H. Zhao, Z. Jin, H. Su, J. Zhang, X. Yao, H. Zhao, G. Zhu, Chem.
Commun. 2013, 49, 2780-2782; b) Y. Yuan, F. X. Sun, L. N. Li, P. Cui,
G. S. Zhu, Nat. Commun. 2014, 5, 4260-4260; c) C. H. Lau, K. Konstas,
A. W. Thornton, A. C. Liu, S. Mudie, D. F. Kennedy, S. C. Howard, A. J.
Hill, M. R. Hill, Angew. Chem. Int. Ed. 2015, 54, 2669-2673; d) X. Zou,
G. Zhu, Adv. Mater. 2018, 30, 1700750; e) L. Wang, J. Jia, M. Faheem,
Y. Tian, G. Zhu, J. Ind. Eng. Chem. 2018, 67, 373-379.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.202000093
COMMUNICATION
[
7]
8]
H. Ma, B. Li, L. Zhang, D. Han, G. Zhu, J. Mater. Chem. A 2015, 3,
9346-19352.
[10] L.-P. Jing, J.-S. Sun, F. Sun, P. Chen, G. Zhu, Chem. Sci. 2018, 9,
3523-3530.
1
[
a) E. Merino, E. Verde-Sesto, E. M. Maya, M. Iglesias, F. Sánchez, A.
Corma, Chem. Mater. 2013, 25, 981-988; b) Y. Zhang, B. Li, S. Ma,
Chem. Commun. 2014, 50, 8507-8510; c) E. Verde-Sesto, M. Pintado-
Sierra, A. Corma, E. M. Maya, J. G. de la Campa, M. Iglesias, F.
Sanchez, Chem. Eur. J. 2014, 20, 5111-5120; d) E. Verde-Sesto, E.
Merino, E. Rangel-Rangel, A. Corma, M. Iglesias, F. Sánchez, ACS
Sustainable Chem. Eng. 2016, 4, 1078-1084; e) E. Rangel-Rangel, E.
Verde-Sesto, A. M. Rasero-Almansa, M. Iglesias, F. Sánchez, Catal.
Sci. Technol. 2016, 6, 6037-6045; f) Y. Yuan, Y. Yang, M. Faheem, X.
Zou, X. Ma, Z. Wang, Q. Meng, L. Wang, S. Zhao, G. Zhu, Adv. Mater.
[11] a) J. P. Hallett, T. Welton, Chem. Rev. 2011, 111, 3508-3576; b) S.
Tang, G. A. Baker, H. Zhao, Chem. Soc. Rev. 2012, 41, 4030-4066; c)
R. Hayes, G. G. Warr, R. Atkin, Chem. Rev. 2015, 115, 6357-6426; d)
A. S. Amarasekara, Chem. Rev. 2016, 116, 6133-6183; e) C. Dai, J.
Zhang, C. Huang, Z. Lei, Chem. Rev. 2017, 117, 6929-6983; f) T. Itoh,
Chem. Rev. 2017, 117, 10567-10607; g) S. Zhang, J. Zhang, Y. Zhang,
Y. Deng, Chem. Rev. 2017, 117, 6755-6833; h) D. J. Eyckens, L. C.
Henderson, Front. Chem. 2019, 7, 263.
[12] L. Zhang, J. S. Sun, F. Sun, P. Chen, J. Liu, G. Zhu, Chem. Eur. J.
2019, 25, 3903-3908.
2018, 30, 1800069.
[9]
a) J. S. Sun, L. P. Jing, Y. Tian, F. Sun, P. Chen, G. Zhu, Chem.
Commun. 2018, 54, 1603-1606; b) P. Chen, J.-S. Sun, L. Zhang, W.-Y.
Ma, F. Sun, G. Zhu, Sci. China Mater. 2018, 62, 194-202.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.202000093
COMMUNICATION
Entry for the Table of Contents
COMMUNICATION
Two new porous aromatic framework
supported ionic liquids have been
synthesized via a serious of post-
functionalization reactions. Thereinto,
PAF-111-IL(OH) is capable of
catalyzing Knoevenagel condensation
reaction in aqueous system with high
catalytic activity and excellent
recyclability.
Dr. Peng Chen, Lei Zhang, Jin-Shi Sun,
En-Kai Xiao, Xian-Tao Wu, Prof.
Guangshan Zhu*
Page No. – Page No.
An Ionic Liquid on a Porous Organic
Framework Support: A Recyclable
Catalyst for the Knoevenagel
Condensation in an Aqueous System
This article is protected by copyright. All rights reserved.