Synthesis of cyclic carbonate from epoxide and CO2 catalyzed by magnetic nanoparticle-supported porphyrin

Article abstract of DOI:10.1016/j.catcom.2010.12.024

A magnetic nanoparticle (MNP)-supported biomimetic cobalt porphyrin as cytochrome P-450 model was designed, prepared and evaluated as an efficient catalyst for coupling reaction of epoxide and CO₂ under 1.0 MPa CO₂ pressure at ambien

Full text of DOI:10.1016/j.catcom.2010.12.024

Catalysis Communications 12 (2011) 684–688
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Catalysis Communications
journal homepage: www.elsevier.com/locate/catcom
Short Communication
Synthesis of cyclic carbonate from epoxide and CO2 catalyzed by magnetic
nanoparticle-supported porphyrin
⁎
Dongsheng Bai, Qiong Wang, Yingying Song, Bo Li, Huanwang Jing
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou, Gansu 730000, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 3 October 2010
Received in revised form 14 December 2010
Accepted 16 December 2010
Available online 23 December 2010
A magnetic nanoparticle (MNP)-supported biomimetic cobalt porphyrin as cytochrome P-450 model was
designed, prepared and evaluated as an efficient catalyst for coupling reaction of epoxide and CO2 under
1.0 MPa CO2 pressure at ambient temperature to generate relevant cyclic carbonate with excellent selectivity
in high yield. The supported porphyrin catalyst could be simply recycled with the assistance of an external
magnet and reused for 16 times without significant loss of activity and mass.
© 2010 Elsevier B.V. All rights reserved.
Keywords:
Epoxide
Cyclic carbonate
Coupling reaction
Magnetic nanoparticle
Supported porphyrin
1. Introduction
could be simply recycled and reused for 16 times without significant
loss of activity.
The chemistry of carbon dioxide has received much attention in
decades from both economical and environmental points of view:
utilization of the least-expensive carbon source and reduction of
global-warming gas [1]. One of the most successful examples is the
synthesis of cyclic carbonates from CO2 and epoxides. The cyclic
carbonates have been widely used as synthetic intermediates, aprotic
polar solvents, precursors for biomedical applications and raw
materials for engineering plastics [2–16]. Various catalysts including
alkali metal salts, Lewis acids, transition metal complexes, ionic
liquids and organometallic compounds, have been developed for the
coupling reaction of epoxide and carbon dioxide to yield cyclic
carbonate in recent years [17–24]. However, those homogeneous
catalysts have obvious drawbacks of recovery and reutilization.
Hence, the immobilization of homogeneous catalysts, especially
biomimetic catalysts such as metalloprophyrins, is much desired.
For fixing our biomimetic catalyst of metalloporphyrin, we have
recently regarded that the catalysts supported by the Fe3O4 magnetic
nanoparticle have been developed and used in various reactions [25–32]
due to their superparamagnetism property, large surface area to volume
ratios that is easy to be functionalized [33]. In this paper, the Fe3O4
magnetic nanoparticle-supported porphyrinato cobaltIII (MNP-P) has
been designed, synthesized (Scheme 1) and evaluated as a recoverable
catalyst for coupling reaction of epoxide and CO2 (Scheme 2). The
greatest advantage of magnetic nanoparticle-supported porphyrin
2. Experimental
2.1. Materials and instrumentations
Propylene oxide (PO), epichlorohydrin, 1,2-epoxybutane,
1,2-epoxydodecane and 1,2-epoxy-3-phenoxypropane were pur-
chased from Aldrich. Styrene oxide and cyclohexene oxide were
obtained from Alfa Aesar. Oxirane was obtained from Beijing Chemical
Reagent Corporation. Tetrabutylammonium fluoride (TBAF), tetra-
butylammonium chloride (TBAC), tetrabutylammonium bromide
(TBAB), tetrabutylammonium iodide (TBAI) and phenyltrimethylam-
monium tribromide (PTAT) were purchased from Sinopharm
Chemical Reagent Co., Ltd. Toluene was distilled from Na–K alloy.
Propylene oxide and n-hexane were distilled from CaH2. Other
epoxides were used to the reaction without further purification
unless otherwise indicated.
Infrared spectra were collected on a Nicolet NEXUS 670 FT-IR
spectrometer using a KBr pallet. ICP data were evaluated on an
inductively coupled plasma atomic emission spectrometer of Thermo
Fisher Scientific CP-IRIS Advantage. TEM was obtained using a JEOL
JEM-2010 F transmission electron microscope (operated at 200 kV).
The variable temperature magnetic susceptibility data of complex
were recorded on SQUID magnetometer using the polycrystalline
sample in the range of 300 to 2 K. The XRD patterns were acquired on
Bruker SMART APEX II X-ray diffractometer. GC analyses of cyclic
carbonates were carried out on a Varian CP-3800 gas chromatograph
equipped with FID detectors.
⁎
Corresponding author. Tel.: +86 931 891 2585; fax: +86 931 891 2582.
E-mail address: jing-hw@163.com (H. Jing).
1566-7367/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.catcom.2010.12.024

D. Bai et al. / Catalysis Communications 12 (2011) 684–688
685
Scheme 1. General procedure for the synthesis of MNP-P catalyst.
2.2. Preparation of free-base porphyrin 1 and metalloporphyrin 2
2.4. Synthesis of Fe3O4 superparamagnetic nanoparticles and Fe3O4
supported cobalt porphyrin 4
Free-base porphyrin 5,10,15,20-tetra-o-aminophenylporphyrin 1
(H2TAPP) and its cobaltIII complex 5,10,15,20-tetra-o-aminophenyl-
porphyrinato cobalt 2 (CoIIITAPP) were synthesized, purified and
characterized following the procedures of literature [22].
Magnetic nanoparticles of Fe3O4 were prepared following the
procedure of literature [34]. Fe(acac)3 (0.706 g, 2 mmol) was added to
a mixture of benzyl ether (10 ml) and oleylamine (10 ml) in a round-
bottom flask. The above solution was heated to 110 °C and kept for 1 h
under nitrogen, then quickly heated to 300 °C and maintained at this
temperature for 2 h. A black-brown mixture was obtained and cooled to
room temperature. The mixture was washed with ethanol (40 ml) and
the precipitate was collected by centrifugation at 8000 rpm. Finally, the
product was redispersed in hexane. The transmission electron micro-
scope (TEM) of Fe3O4 demonstrates that the average diameter of this
magnetic Fe3O4 nanoparticles were 5–8 nm (Fig. 1a). The XRD patterns
and magnetic curves were shown in Fig. 1b and Fig. 1c respectively.
The general procedure for synthesis of MNP-P catalyst was shown in
Scheme 1. A mixture of MNP (96 mg, 0.42 mmol), cobalt porphyrin 3
(178 mg, 0.1 mmol) and anhydrous toluene (20 ml) was ultra-sonicated
for 2 min and then heated to reflux for 12 h. After cooling to room
temperature, the reaction mixture was separated by decantation using
an external magnet and washed with CH2Cl2 (3 ml×3) to obtain a dark-
brown powder 4. The quantity of metalloporphyrin catalyst coating was
0.4966 mmol/g determined by ICP. TEM, XRD and magnetic curve of
reused MNP-P were shown in Fig. 1 a1, b1 and c1. IR (cm−1) of MNP-P:
3378.5 (υN–H, m, br), 3060.6 (υAr–H, w), 2997.5 (w), 2923.1 (s), 2854.6
(υC–H, w), 1641.8 (υC O, m), 1580.0 (sh), 1549.2 (m), 1529.9 (m), 1442.7
(υAr, s), 1073.9 (υSi–O, vs), 1002.2 (υSi–C, s), 756.1 (υAr–H, bending, m).
2.3. Preparation of functionalized cobalt porphyrin 3
3-Isocyanatopropyltriethoxysilane (0.1 ml, 0.4 mmol) was added
to a solution of metalloporphyrin 2 (79 mg, 0.1 mmol) in toluene
(10 ml). The mixture was stirred for 12 h at 85 °C. After cooling to
room temperature, the reaction mixture was concentrated under
reduced pressure. The obtained solid was washed with hexane for
three times and dried in vacuum to generate functionalized cobalt
porphyrin 3 165 mg (93% yield) as a purple solid.
Characterization of porphyrin 3: 1H NMR (300 MHz, CDCl3)
δ=0.82 (m, 8H; CH2), 0.96 (t, J=9.0 Hz, 36H; CH3), 1.38 (m, 8H;
CH2), 2.49 (m, 8H; CH2), 3.5 (m, 24H; CH2), 3.82 (s, 3H; CH3), 4.70
(s, 8H; NH), 7.41 (m, 4H; β-pyrrole H), 7.74 (m, 4H; β-pyrrole H), 7.94
(m, 4H; o-aryl H), 8.28 (m, 4H; p-aryl H), 8.76 (m, 8H; m-aryl H); 13C
NMR (300 MHz, CDCl3) δ=8.38, 19.3, 24.3, 43.6, 55.8, 60.2, 116.5,
120.0, 123.0, 130.9, 132.7, 135.2, 135.6, 140.3, 141.0, 151.0, 156.0, and
156.7. Anal. Calcd for C86H119N12O18Si4Co: C, 58.02; H, 6.74; N, 9.44.
Found: C, 57.86; H, 6.88; N, 9.18. IR (cm−1) 3350.1 (υN–H, m, br),
3060.6 (υAr–H, w), 2970.1 (m), 2923.8 (m), 2880.9 (υC–H, m), 1667.5
(υC O, s), 1580.0 (w), 1521.2 (vs), 1441.9 (υAr, s), 1073.9 (υSi–O, vs),
999.6 (υSi–C, s), and 756.0 (υAr–H, bending, m).
2.5. General procedure for synthesis of cyclic carbonates
All coupling reactions were carried out in a 100 ml stainless steel
autoclave equipped with a 10 ml glass tube. The tube in the autoclave
was equipped with a stir bar and charged with MNP-P (43 mg), Lewis
base (0.08 mmol) and epoxide (15 mmol) without additional solvent
unless otherwise indicated. The autoclave was pressurized with CO2
to 1.0 MPa and then stirred at room temperature. After a proper time,
when the pressure fell down to 0.7 MPa, the reactor was vented. The
Scheme 2. Coupling reaction catalyzed by MNP-P/PTAT.

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D. Bai et al. / Catalysis Communications 12 (2011) 684–688
Fig. 1. a) The TEM image of Fe3O4 nanoparticles (a), MNP-P (a1), recovery MNP-P (a2); The XRD patterns of Fe3O4 nanoparticles (b), MNP-P (b1), recovery MNP-P (b2); The magnetic
curve of Fe3O4 nanoparticles (c), MNP-P (c1), recovery MNP-P (c2).
remaining mixture was dissolved in 1 ml CH2Cl2. The catalyst MNP-P
was separated by an external magnet (Fig. 2. b). After distillation of
unreacted epoxide and solvent at room temperature, the residue was
then distilled under reduced pressure at about 90 °C to give a pure
cyclic carbonate as a colorless liquid, or a solid product that was
recrystallized with ethanol to obtain the pure cyclic carbonate.
2.6. Recycling procedure of MNP-P catalyst
Dichloromethane was added to dilute the reaction mixture after
terminating the reaction. The catalyst of MNP-P was quickly subsided
to the bottom of the reaction tube when an external magnet was used.
Then, the obtained liquid containing the cyclic carbonate can be easily
decanted. The recovery MNP-P was washed with CH2Cl2 (3 ml) and
epoxide (3 ml) for five times respectively, then reused directly to the
next run with another portion of co-catalyst of PTAT. TEM, XRD and
magnetic curve of reused MNP-P were shown in Fig. 1 a2, b2 and c2.
3. Results and discussion
3.1. Co-catalyst effect on the synthesis of propylene carbonate from
propylene oxide and CO2
The MNP-P was used as catalyst and quaternary ammonium salt was
used as co-catalyst in the model reaction of propylene oxide and CO2. As
shown in Table 1, the reaction took place smoothly in the presence of
catalysts affording the desired propylene carbonate (PC) in high yield.
The use of PTAT was shown to accelerate the reaction (Table 1, entries
1–3 vs. 7) and the activity of catalytic system increased with higher PTAT
loading (Table 1, entries 5–8). The tetrabutylammonium iodide almost
Fig. 2. a) The MNP-P was dispersed in PO; b) The MNP-P was separated with an external
magnet.

D. Bai et al. / Catalysis Communications 12 (2011) 684–688
687
Table 1
The IR spectra of recovery catalyst showed the same peaks as the
new MNP-P catalyst. Hence, there was no leaching of porphyrin from
the support during the reaction. From the measurements of TEM of
recovery catalyst (Fig. 1, a2), we can see that the diameters of catalyst
were the same size compared with the fresh catalyst (Fig. 1, a1) and
the precursor (Fig. 1a). Comparing the XRD patterns of reused catalyst
(Fig. 1, b2) with that of fresh catalyst (Fig. 1, b1) and Fe3O4 (Fig. 1b),
the crystal lattice of catalyst was not changed; The magnetic curves of
MNP-P (Fig. 1. c1) showed a decrease after coating the porphyrin 3 to
Fe3O4 nanoparticles due to the diamagnetism of organic groups, and
the magnetic curves of reused MNP-P (Fig. 1 c2) was decreased again
after 16 recycles that did not influence their recyclability.
Synthesis of cyclic carbonate from propylene oxide (PO) and CO2 catalyzed by MNP-Pa.
Entry
Catalyst
Co-catalyst/mmol
Reaction time (h)
Yield (%)b
1
2
3
4
5
6
7
8
MNP-P
MNP-P
MNP-P
MNP-P
MNP-P
MNP-P
MNP-P
MNP-P
-
TBAF/0.08
TBAC/0.08
TBAB/0.08
TBAI/0.08
PTAT/0.02
PTAT/0.04
PTAT/0.08
PTAT/0.16
PTAT/0.08
–
24
24
24
24
24
24
24
16
24
24
24
10
26.9
35.2
74.5
97.9
38.6
93.1
97.2
93.1
21.4
–
9c
10d
11d
MNPs
MNP-P
Co(TAPP)(OAc)
–
–
e
12
PTAT/0.08
88.3
3.3. Cycloaddition of various epoxides with CO2
a
Reaction conditions: PO, 15 mmol; MNP-P, 43 mg; CO2 pressure, 1.0 MPa; 25 °C.
Isolated yield, the selectivity determined by GCN99.9%.
Without MNP-P.
When MNPs or MNP-P was used only as catalyst, no reaction was occurred.
Catalyst Co(TAPP)(OAc) catalyst, 16 mg.
b
c
Under the optimized reaction condition, the scope of substrates
was then extended using MNP-P as catalyst (Table 2). As shown in
Table 2, MNP-P/PTAT catalytic system can initiate the coupling
reaction of a number of epoxides and CO2 to generate the
corresponding cyclic carbonates in high yield (Table 2, entries 1, 2,
3 and 7). The coupling reaction of styrene oxide (Table 2, entry 6) and
phenoxypropylene oxide (Table 2, entry 7) and CO2 must be
performed with dilute solvent of CH2Cl2 respectively due to their
corresponding cyclic carbonates are solids. This catalytic system can
d
e
has the same superior activity as PTAT due to the higher nucleophilicity
of iodide ion (Table 1, entry 4 vs. 7). Although the propylene carbonate
can be obtained with the using of PTAT only (Table 1, entry 9), the
addition of MNP-P significantly accelerated this coupling reaction
(Table 1, entries 1–8). The activity of the MNP-P catalyst in terms of
accompanied cocatalyst is in the order of PTATNTBAINTBACNTBAF. This
result was consistent with the literature report [13].
Table 2
The coupling results of various epoxides and CO2 catalyzed by MNP-P/PTATa.
Entry Reactant
1
Product
Reaction time (h) Yield (%)b
3.2. Recycling of MNP-P catalyst
24
24
97.6
97.2
Since the metalloporphyrins used as catalysts are highly expensive
materials, the recovery and reuse are the key factors which limit their
applications in synthetic chemistry and industrial processes. The
recycling of MNP-P catalyst was then investigated. The product
separation and the recycling of the biomimetic catalyst MNP-P were
indeed quite easy and simple using an external magnet (Fig. 2a, b).
When the yield of PC was dropped down for 3% (Fig. 3, entries 1, 4, 6,
10, 13 and 15), the MNP-P catalyst needed to be reoxidized in 5 ml
CH2Cl2 with extra addition of 0.1 ml acetic acid in an open flask for five
hours or in a dioxygen atmosphere for one hour in order to recover its
catalytic activity, then washed with CH2Cl2 and PO for five times
(3 ml×5) respectively, and then reused directly to the next run. The
catalyst can be recycled for 16 times in this manner (Fig. 3) without
significantly loss of activity. Then the recovery catalyst of MNP-P was
washed and dried in vacuum. The weight of it was still 43 mg.
2
3
24
36
24
93.1
52.4
44.2
4
5c
6c
36
48.7
7c
24
48
91.7
8.9
8
a
Reaction conditions: epoxide, 15 mmol; MNP-P, 43 mg; PTAT, 0.08 mmol; CO2
1.0 MPa; 25 °C.
b
c
Fig. 3. Recycling of MNP-P catalyst. Reaction conditions: PO, 15 mmol; MNP-P, 43 mg;
PTAT, 0.08 mmol; CO2, 1.0 MPa; time, 24H; temperature 25 °C.
Isolated yield, the selectivity determined by GCN99.9%.
CH2Cl2, 1 ml.

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[5] W.N. Sit, S.M. Ng, K.Y. Kwong, C.P. Lau, J. Org. Chem. 70 (2005) 8583–8586.
[6] A. Berkessel, M. Brandenburg, Org. Lett. 8 (2006) 4401–4404.
[7] H.S. Kim, J.J. Kim, S.D. Lee, M.S. Lah, D. Moon, H.G. Jang, Eur. Chem. J. 9 (2003)
678–686.
[8] K.C. Nicolaou, Z. Yang, J.J. Liu, H. Ueno, P.G. Nantermet, R.K. Guy, C.F. Claiborne, J.
Renaud, E.A. Couladouros, K. Paulvannan, E.J. Sorensen, Nature 367 (1994) 630–634.
[9] T. Takata, Y. Furusho, K.-I. Murakawa, T. Endo, H. Matsuoka, T. Hirasa, J. Matsuo, M.
Sisido, J. Am. Chem. Soc. 120 (1998) 4530–4531.
[10] H.T. Chang, K.B. Sharpless, Tetrahedron Lett. 37 (1996) 3219–3222.
[11] H. Jing, S.T. Nguyen, J. Mol, Catal. A Chem. 261 (2007) 12–15.
[12] J.M. Sun, S.I. Fujita, F.Y. Zhao, M. Arai, Green Chem. 6 (2004) 613–616.
[13] X.-B. Lu, B. Liang, Y.J. Zhang, Y.Z. Tian, Y.M. Wang, C.X. Bai, H. Wang, R. Zhang, J.
Am. Chem. Soc. 126 (2004) 3732–3733.
also be realized in the coupling reaction of cyclohexene oxide (CHO)
and CO2 to obtain the cyclohexene carbonate (8.9%, Table 2, entry 8)
that is difficult to get in many catalyst systems. To estimate the purity
of cyclic carbonates, the IR spectroscopy was used and gave only one
peak at around 1795 cm−1 attributed to the carbonyl group in cyclic
carbonate. However, the peak of 1749 cm−1 was not detected, which
was attributed to the carbonyl group in polycarbonate [35]. The gas
chromatography technology was used to detect the impurities. The GC
traces showed that there was no other by-product.
[14] Y. Xie, Z.F. Zhang, T. Jiang, J.H. He, B.X. Han, T.B. Wu, K.L. Ding, Angew. Chem. Int.
Ed. 46 (2007) 7255–7258.
4. Conclusions
[15] S.L. Zhang, Y.Z. Huang, H.W. Jing, W.X. Yao, P. Yan, Green Chem. 11 (2009)
935–938.
In summary, we have synthesized a new MNPs-supported
biomimetic cobalt porphyrin as an efficient and recyclable catalyst
for the coupling reaction of epoxides and CO2 to generate relevant
cyclic carbonate with excellent selectivity in high yield. The product
separation and catalyst recycling are concise using an external
magnet. The MNP-P catalyst can be recovered and reused up to 16
times without significant loss of activity and mass.
[16] T. Chang, L.L. Jin, H.W. Jing, ChemCatChem 1 (2009) 379–783.
[17] P. Yan, H.W. Jing, Adv. Synth. Catal. 351 (2009) 1325–1332.
[18] W.J. Kruper, D.V. Dellar, J. Org. Chem. 60 (1995) 725–727.
[19] H. Sugimoto, T. Kimura, S. Inoue, J. Am. Chem. Soc. 121 (1999) 2325–2326.
[20] R.L. Paddock, Y. Hiyama, J.M. McKay, S.T. Nguyen, Tetrahedron Lett. 45 (2004)
2023–2026.
[21] R. Srivastava, T.H. Bennur, D. Srinivas, J. Mol, Catal. A Chem. 226 (2005) 199–205.
[22] L.L. Jin, H.W. Jing, T. Chang, X.L. Bu, L. Wang, Z.L. Liu, J. Mol, Catal. A Chem. 261
(2007) 262–266.
[23] D.S. Bai, X.X. Wang, Y.Y. Song, B. Li, L.L. Zhang, P. Yan, H.W. Jing, Chin. J. Catal. 31
(2010) 51–59.
Acknowledgements
[24] V. Caló, A. Nacci, A. Monopoli, A. Fanizzi, Org. Lett. 4 (2002) 2561–2563.
[25] A. Hu, G.T. Yee, W. Lin, J. Am. Chem. Soc. 127 (2005) 12486–12487.
[26] S. Ko, J. Jang, Angew. Chem. Int. Ed. 45 (2006) 7564–7567.
[27] M. Kawamura, K. Sato, Chem. Commun. (2006) 4718–4719.
[28] G. Chouhan, D. Wang, H. Alper, Chem. Commun. (2007) 4809–4811.
[29] M. Shokouhimehr, Y. Piao, J. Kim, Y. Jang, T. Hyeon, Angew. Chem. Int. Ed. 46
(2007) 7039–7043.
This research was supported by the National Natural Science
Foundation of China (NSFC 20973086). We are grateful to Professor
Wei Wang for help with the material of magnetic nanoparticles, TEM
and magnetic measurements.
[30] R. Abu-Reziq, D. Wang, M.L. Post, H. Alper, Chem. Mater. 20 (2008) 2544–2550.
[31] V. Polshettiwar, R.S. Varma, Chem. Eur. J. 15 (2009) 1582–1586.
[32] X.X. Zheng, S.Z. Luo, L. Zhang, J.-P. Cheng, Green Chem. 11 (2009) 455–458.
[33] A. Hu, G.T. Yee, W. Lin, J. Am. Chem. Soc. 127 (2005) 12486–12487.
[34] Z.C. Xu, C.M. Shen, Y.L. Hou, H.J. Gao, S.H. Sun, Chem. Mater. 21 (2009) 1778–1780.
[35] Y.S. Niu, W.X. Zhang, H.C. Li, X.S. Chen, J.R. Sun, X.L. Zhuang, X.B. Jing, Polymer 50
(2009) 441–446.
References
[1] D.J. Darensbourg, R.M. Mackiewicz, A.L. Phelps, D.R. Billodeaux, Acc. Chem. Res. 37
(2004) 836–844.
[2] W. Yamada, Y. Kitaichi, H. Tanaka, T. Kojima, M. Sato, T. Ikeno, T. Yamada, Bull.
Chem. Soc. Jpn 80 (2007) 1391–1401.
[3] R.L. Paddock, S.T. Nguyen, J. Am. Chem. Soc. 123 (2001) 11498–11499.
[4] M. Aresta, A. Dibenedetto, L. Gianfrate, C. Pastore, J. Mol, Catal. A Chem. 204–205
(2003) 245–252.