Catalytic fixation of CO2 to cyclic carbonates by phosphonium chlorides immobilized on fluorous polymer

Article abstract of DOI:10.1039/c2gc36210d

Phosphonium chloride covalently bound to the fluorous polymer is proved to be an efficient and recyclable homogeneous CO₂-soluble catalyst for organic solvent-free synthesis of cyclic carbonates from epoxides and CO ₂ under supercrit

Full text of DOI:10.1039/c2gc36210d

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Catalytic fixation of CO2 to cyclic carbonates by
phosphonium chlorides immobilized on fluorous
polymer†
Cite this: Green Chem., 2013, 15, 110
Qing-Wen Song,a Liang-Nian He,*a,b Jin-Quan Wang,a Hiroyuki Yasudab and
Toshiyasu Sakakura*b
Phosphonium chloride covalently bound to the fluorous polymer is proved to be an efficient and recycl-
able homogeneous CO2-soluble catalyst for organic solvent-free synthesis of cyclic carbonates from epo-
xides and CO2 under supercritical CO2 conditions. The catalyst can be easily recovered by simple filtration
after reaction and reused with retention of high activity and selectivity. In addition, the effects of various
reaction variables on the catalytic performance are also discussed in detail. The process represents a
simpler access to preparing cyclic carbonates with the ease of homogeneous catalyst recycling.
Received 1st August 2012,
Accepted 24th September 2012
DOI: 10.1039/c2gc36210d
www.rsc.org/greenchem
For the cyclic carbonate synthesis from CO2 and epoxides,
numerous effective catalytic systems have been developed
Introduction
Recently, CO2 fixation has received much attention because including homogeneous5 and heterogeneous catalysis.6 We
CO2 is the most inexpensive and renewable carbon resource have reported that a fluorous phosphonium catalyst5k can be
from the viewpoint of green chemistry and atom economy.1 used in scCO2 as a homogeneous catalyst, and this process
Development of a truly environmentally friendly process utiliz- offers the advantage of allowing the synthesis of e.g. PC to take
ing CO2, which is the largest single source of greenhouse gas place under supercritical conditions with the direct and spon-
and can also be regarded as a typical renewable natural taneous separation of the carbonate. Recently, attachment of
resource, has drawn current interest in synthetic chemistry fluorinated chains to chelating agents, surfactants, and cata-
from the viewpoint of environmental protection and resource lyst ligands could generally enhance the solubility of such
utilization. In this regard, chemical fixation of CO2 onto indus- compounds in scCO2, and thus can be used to design CO2-
trial useful materials is one of the most promising methods soluble catalysts.7 In this context, a phosphonium chloride
because there are many possibilities for CO2 to be used as a covalently bound to the fluorous polymer (Scheme 1) was
safe and cheap C1 building block in organic synthesis.2 On the
other hand, supercritical CO2 (scCO2) is considered to be a
green solvent, and thus substantial effort has been devoted to
developing chemical processes in which scCO2 is used to
replace hazardous organic solvent.3
Organic cyclic carbonates such as ethylene carbonate and
propylene carbonate (PC) have been widely used for various
purposes, for instance, electrolytic elements of lithium second-
ary batteries, polar aprotic solvents, monomers for synthesiz-
ing polycarbonates, and chemical ingredients for preparing
medicines or agricultural chemicals.4
aState Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin,
300071, P. R. China. E-mail: heln@nankai.edu.cn; Tel: +86 22 2350 3878
bNational Institute of Advanced Industrial Science and Technology (AIST), Tsukuba
Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
E-mail: t-sakakura@aist.go.jp; Tel: +81 29 861 4559
†Safety warning: Experiments using compressed CO2 gas are potentially hazar-
dous and must only be carried out by using the appropriate equipment and
under rigorous safety precautions.
Scheme 1 Synthesis of fluorous polymers supported phosphonium chloride.
110 | Green Chem., 2013, 15, 110–115
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solubility of phosphonium salts that are usually insoluble in
scCO2. Therefore, the catalyst (4a) was selected as the model
catalyst for further investigation.
The influence of reaction temperature on PC yield was
further studied. It was found that the yield of PC was strongly
affected by the reaction temperature. The yield and selectivity
of PC increased with the reaction temperature up to 150 °C
(entries 1 and 7–9, Table 1), whereas further increase in the
temperature caused a decrease in the selectivity, possibly due
to facile formation of side-products at the higher temperature,
i.e. the isomerisation of PO to acetone and the ring opening by
water to propylene glycol. From a practical viewpoint, appar-
ently, 150 °C could be the optimal and desirable temperature.2f
Moreover, 1 mol% of the catalyst is a proper amount for the
reaction (entries 1, 10, 11).
Fig. 1 shows the influence of reaction time on PC yield. The
supported phosphonium chloride-catalyzed PC synthesis from
PO and CO2 proceeded rapidly, and more than 80% PC yield
was obtained within the first 2 h at 150 °C. The PC yield experi-
enced a continuing growth within 6 h, while the selectivity of
PC remained almost constant during the whole course of the
reaction. Consequently, a reaction time of 6 h was required for
almost complete PO conversion.
Scheme 2 Synthesis of propylene carbonate from propylene oxide and CO2.
employed to design such a supported catalyst that can homo-
geneously dissolve during the reaction and precipitate quanti-
tatively in the separation stage.
The fluorous polymers 4a and 4b were identified by 1H
NMR, 13C NMR, 19F NMR, FT-IR elementary analysis7d and
GPC measurement. The reaction of propylene oxide (PO) and
CO2 performed well with 98% of PC yield and excellent selec-
tivity, as shown in Scheme 2. Notably, incorporation of the
fluorinated chain in the polymer effectively enhance the solu-
bility of phosphonium salts which are usually insoluble in
scCO2, thus providing a simple way for performing homo-
geneous catalysis under scCO2 conditions.
Results and discussion
It is well-known that the properties of supercritical fluids
are sensitive to pressure, and thus pressure may drastically
influence the reaction outcome when a reaction takes place in
supercritical conditions. The effect of CO2 pressure on the
yield and selectivity of PC is depicted in Fig. 2. The selectivity
The coupling of PO and CO2 was conducted in a batch-wise
operation in the presence of 1 mol% of the catalyst with
respect to the initial amount of PO under identical conditions
(150 °C, 8 MPa, 8 h). The results are summarized in Table 1. It
is worthwhile mentioning that the fluorous polymer (3a) itself
can hardly catalyze the cycloaddition reaction under the reac-
tion conditions (entry 3, Table 1). Interestingly, phosphonium
chloride covalently bound to fluorous polymers (4a and 4b)
exhibited high activity, higher than Bu4PCl (entries 1, 2 vs. 4),
the corresponding lower molecular weight catalyst; even
higher than KI and Bu4NBr (entries 1, 2 vs. 5, 6), traditional
homogeneous catalysts for PC synthesis in industrial appli-
cation. It is most possible that the incorporation of the fluori-
nated side chain in the polymer effectively enhances the
Fig. 1 Reaction time – the PC yield profile. Reaction conditions: propylene
oxide (28.6 mmol); catalyst 4a (1 mol%); 150 °C; 8 MPa.
Table 1 Synthesis of propylene carbonate from propylene oxide and CO2
using various catalystsa
Entry
Cat.
Temperature (°C)
Yieldb (%)
Selectivityb (%)
1
2
3
4
5
6
7
8
4a
4b
3a
Bu4PCl
Bu4NBr
KI
4a
4a
150
150
150
150
150
150
90
120
180
150
150
98
97
5
99
97
–
90
95
89
21
58
81
82
98
99
98
96
99
>99
90
99
99
9
4a
4a
4a
10c
11d
a Reaction conditions: propylene oxide (28.6 mmol); 1 mol% of the
catalyst based on propylene oxide; CO2 8 MPa; 8 h. b Determined by GC
using biphenyl as an internal standard. c 0.5 mol% of the catalyst.
d 2 mol% of the catalyst.
Fig. 2 Reaction pressure – the PC yield profile. Reaction conditions: propylene
oxide (28.6 mmol); catalyst 4a (1 mol%); 150 °C; 8 h.
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Table 2 Cycloaddition of CO2 with various epoxides catalyzed by 4aa
Yieldb
Selectivity
(%)
Entry
Substrate
Product
(%)
1
98 (93)
99
Scheme 3 Synthesis of various carbonates catalyzed by fluorous polymers-
R3P+X−.
2
3
97 (95)
95 (91)
>99
99
slightly changed in the range of 3–14 MPa. As easily seen, the
best PC yield could be achieved under scCO2 conditions,
demonstrating the preferential effect of the supercritical con-
ditions, while the yield was remarkably influenced by the
pressure below 8 MPa. Possibly, the isomerisation to acetone
increased or the CO2 insertion step was limited at low CO2
pressure.
The scope of the substrates was further explored as shown
in Scheme 3 and Table 2. Several terminal epoxides were
chosen to be tested under the optimized reaction conditions.
The catalyst (4a) was found to be applicable to a variety of
terminal epoxides, yielding the corresponding cyclic carbon-
ates in excellent yields with more than 99% selectivity (entries
1–5, Table 2). This catalyst can also be utilized in the coupling
reaction of CO2 and optical pure epoxide, (R)-styrene oxide to
conveniently obtain (R)-1-phenyl-1,2-ethanediol carbonate (R-
6c) in 99% ee with retention of stereochemistry (entry 6).8
The facility of recycling the catalysts is one of the key advan-
tages in this catalytic system. As shown in Fig. 3, a single
homogeneous phase was formed under reaction conditions
(100 °C, 14 MPa5k or 150 °C, 8 MPa). Indeed, the phase behav-
iour of the reaction visually inspected through a sapphire
window attached to the autoclave6q revealed that the reaction
mixture initially formed a uniform phase, while propylene car-
bonate formed a new phase upon the reaction. After the reac-
tion, the catalyst was precipitated as a solid upon venting CO2.
4
99 (94)
99
5
6
91 (88)
98
99
97
As a result, the catalyst was easily recovered by simple fil- a Reaction conditions: epoxide (28.6 mmol); catalyst 4a (1 mol%);
temperature 150 °C; CO2 8 MPa; 8 h. b Determined by GC using
tration. A series of repeated reactions run continuously to
investigate the constancy of the catalyst activity. In each cycle,
biphenyl as an internal standard; value in parentheses refers to
isolated yield column chromatography with ethyl acetate–petroleum as
the catalyst was separated by filtration and then used for the the eluent.
next run directly. The results show that the catalyst can be
reused at least 7 times without significant loss of catalytic
activity, while the excellent selectivity of propylene carbonate is
nearly unchanged. Furthermore, the purity of the product sep-
arated directly by filtration from the reaction mixture, reached
99% without further purification process.
A possible mechanism for the fluorous polymer supported
phosphonium chloride-catalyzed coupling of epoxides with
CO2 in this study would be similar to that of ammonium/phos-
phonium salt catalysis.5d,s The proposed mechanism involves
the activation of propylene oxide by the phosphonium cation,
the ring-opening of the epoxide via nucleophilic attack of
chloride at the least-hindered carbon, and the insertion of CO2
into the N–O bond. Subsequent cyclization via an intramolecu-
lar nucleophilic attack leads to the cyclic carbonate and the
regeneration of the catalyst.
Fig. 3 Catalytic activity of the reused CO2-soluble catalyst (4a). Reaction con-
ditions: propylene oxide (28.6 mmol); catalyst 4a (1 mol%); 150 °C; 8 MPa; 8 h.
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1249 (C–F), 1103, and 1012, and 711 (phosphonium salt), 653;
Anal. Calcd for (4a): C, 32.76; H, 1.93; F, 58.3; P, 0.56. Found:
C, 32.43; H, 1.90; F, 57.4; P, 0.44. Mw: 5536.
Experimental
Chemical reagents
1
All chemicals, except CO2, were handled under a nitrogen
Compound 4b: H NMR (FC 77 with an external chloroform-
atmosphere. The catalysts were synthesized by a modified d lock) 7.08–7.64 (br m, 1H), 4.28 (br m, 5H), 3.49 (s, 5H), 2.50
method described in the literature.7d–l (m, 5H), 1.57–1.89 (br m, 20H); 13C NMR (100.6 MHz, FC 77
Preparation of fluoroacrylate copolymer (3a). 1H,1H,2H,2H- with an external chloroform-d lock) 175.50 (s, CvO),
Heptadecafluorodecyl acrylate (1) (6.64 g, 12.8 mmol) and p- 106.61–125.67 (m, Rf), 57.76 (s, OCH2), 42.40 (s, CH2Ph), 31.48
chloromethylstyrene (2) (0.118 g, 0.77 mmol) were dissolved in (t, CH2Rf, JFC = 20.63 Hz), 25.33 (s), 14.47 (s); 31P NMR
50 mL of benzotrifluoride. The flask was evacuated and (161.9 MHz, FC 77 with an external chloroform-d lock) 34.64.
flushed with argon three times and then fitted with a reflux IR (ν, cm−1) 2965 (C–H), 1740 (CvO), 1255 (C–F); Anal. Calcd
condenser. After heating to 80 °C, azobisisobutyronitrile for (4b): C, 31.49; H, 1.66; F, 60.3; P, 0.29. Found: C, 31.14; H,
(AIBN, 0.025 g, 0.15 mmol) in 5 mL of benzotrifluoride was 1.57; F, 60.2; P, 0.24. Mw: 10 718.
added. The reaction was stirred for 2 d at 100 °C and was then
Representative procedure for the cycloaddition reaction
cooled to room temperature. The copolymer 3 was precipitated
1
into 75 mL of methanol. H NMR analysis indicated the pres- In a typical reaction, the cycloaddition reaction of CO2 to pro-
ence of monomer, so the dissolution and precipitation were pylene oxide was carried out in a stainless steel autoclave
repeated again. The copolymer was isolated by filtration and (25 cm3 inner volumes). Prior to the reaction, the catalyst was
dried under vacuum overnight to give a white solid.
evacuated at 150 °C for 3 h. CO2 (gas, 4.0 MPa) was introduced
Compound 3a: 1H NMR (perfluoro-compound FC 77 with to a mixture of propylene oxide (28.6 mmol), catalyst (4a,
drops CDCl3) δ 7.01–7.35 (br m, 1H), 4.27 (s, 5H), 2.46 (s, 5H), 1 mol%), and biphenyl (80 mg, an internal standard for GC
1.40–1.90 (br m, 15H); 13C NMR (100.6 MHz, FC 77 with an analysis) at room temperature. The gauge was used to monitor
external chloroform-d lock) δ 175.52 (s, CvO), 105.73–126.03 the pressure of the system. The initial pressure was adjusted to
(m, Rf), 58.01 (s, OCH2), 31.78 (s, CH2Rf).
8 MPa at 150 °C and the autoclave was heated at that tempera-
Preparation of fluoroacrylate copolymer (3b). 6.64 g of ture for 8 h. After cooling, the products were analyzed on a gas
1H,1H,2H,2H-heptadecafluorodecyl acrylate (1, 12.8 mmol) chromatograph (Agilent 6890) equipped with a capillary
and 4-chloro-α-methylstyrene (2) (0.118 g, 0.77 mmol) were dis- column (HP-5 30 m × 0.25 μm) using a flame ionization detec-
solved in 50 mL of benzotrifluoride. The Schlenk flask used tor. The structure and the purity of the products were further
was evacuated and flushed with argon three times and then identified using GC-MS (HP G1800A) by comparing retention
fitted with a reflux condenser. AIBN (0.025 g, 0.15 mmol) was times and fragmentation patterns with those of authentic
added after heating to 80 °C. The reaction was allowed to samples. The solvent was removed, and the residue was sub-
proceed for 2 d at 100 °C under argon and was then cooled to jected to column chromatography with ethyl acetate–pet-
room temperature. The volume of the solution was reduced to roleum as the eluent to obtain the desired product.
50 mL by vacuum and the copolymer (3b) was precipitated by
The products were also characterized by NMR. 1H NMR and
adding the solution into 75 mL of freshly-distilled methanol. 13C NMR spectra were recorded on a Varian Mercury-plus 400
The copolymer was isolated by filtration and dried under spectrometer. Chemical shifts were given as δ values refer-
vacuum to give 4.98 g of a white solid (yield 75%).
enced in parts per million (ppm) from tetramethylsilane
Compound 3b: H NMR (FC 77) 7.14–7.70 (br m, 1H), 4.52 (TMS) as an internal standard. Spectral characteristics of the
(s, 12H), 1.41–2.63 (br s, 30H). products (cyclic carbonates 2a–e) in Table 2 were provided as
Synthesis of tributylbenzylphosphonium chloride ligated follows:
fluoroacrylate polymer (4a, 4b). In a typical procedure, copoly- 4-Methyl-1,3-dioxolan-2-one
1
(6a). 1H
NMR
(CDCl3,
3
3
mer 3b (4.98 g) was dissolved in 5 mL of trifluorotoluene 400 MHz) δ 1.43 (d, J = 6.0 Hz, 1H, CH3), 3.98 (t, J = 8.4 Hz,
3
under argon in an oven-dried flask. After the flask was flushed 1H, OCH2), 4.51 (t, J = 8.4 Hz, 1H, OCH2), 4.82 (m, 1H, CHO);
with argon, a solution of 202 mg of tributylphosphine in tri- 13C NMR (CDCl3, 100.6 MHz) δ 19.14, 70.52, 73.47, 154.95.
fluorotoluene (10 mL) was then added. The reaction was
stirred at 100 °C for 1 d under an argon atmosphere. The (s, 4H, OCH2); 13C NMR (CDCl3, 100.6 MHz) δ 64.55, 155.36.
product was precipitated into 30 mL of freshly-distilled MeOH
4-Phenyl-1,3-dioxolan-2-one (6c). 1H NMR (CDCl3, 400 MHz)
and isolated by filtration and dried for 6 h under vacuum to δ 4.35 (t, 3J = 8.4 Hz, 1H, OCH2), 4.80 (t, 3J = 8.4 Hz, 1H,
1,3-Dioxolan-2-one (6b). 1H NMR (CDCl3, 400 MHz) δ 4.52
3
3
give slightly yellow solid. Gel permeation chromatography OCH2), 5.70 (t, J = 8.0 Hz, 1H, OCH), 7.36 (d, J = 7.6 Hz, 2H,
(GPC) measurements were carried out on PL-GPC-220 in C6H5), 7.44 (d, 3J = 6.4 Hz, 3H, C6H5); 13C NMR (CDCl3,
hexafluoroisopropanol.
Compound 4a: colorless solid. 1H NMR (FC 77) 7.10–7.90 (br 154.65, 157.71.
m, 2H), 4.46 (s, 25H), 1.40–2.57 (br s, 75H); 13C NMR (FC 77) 4-Phenoxymethyl-1,3-dioxolan-2-one (6d). 1H NMR (CDCl3,
100.6 MHz) δ 66.17, 68.84, 74.11, 114.57, 121.92, 129.62,
3
2
175.22 (s, CvO), 102.98–125.57 (m, Rf), 57.73 (s, OCH2), 42.14 400 MHz) δ 4.15 (dd, J = 4.4 Hz, J = 10.8 Hz, 1H, OCH2), 4.24
3
2
3
(s, CH2Ph), 31.39 (t, CH2CF2, JFC = 21.49 Hz), 25.00 (s); 31P (dd, J = 3.6 Hz, J = 10.8 Hz, 1H, OCH2), 4.55 (dd, J = 8.4 Hz,
NMR (FC 77) 32.97. IR (ν, cm−1), 2973 (C–H), 1737 (CvO), 2J = 6 Hz, 1H, PhOCH2), 4.62 (t, 3J = 8.4 Hz, 1H, PhOCH2), 5.03
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3
3
(m, 1H, OCH), 6.91 (d, J = 8.0 Hz, 2H, C6H5), 7.02 (t, J = 7.4
Hz, 2H, C6H5), 7.31 (t, 3J = 8.0 Hz, 2H, C6H5); 13C NMR (CDCl3,
100.6 MHz) δ 66.17, 68.84, 74.11, 114.57, 121.92, 129.62,
154.65, 157.71.
(e) K. M. K. Yu, I. Curcic, J. Gabriel and S. C. E. Tsang, Chem-
SusChem, 2008, 1, 893; (f) T. Sakakura, J. C. Choi and
H. Yasuda, Chem. Rev., 2007, 107, 2365; (g) D. B. Dell’Amico,
F. Calderazzo, L. Labella, F. Marchetti and G. Pampaloni,
Chem. Rev., 2003, 103, 3857; (h) I. Omae, Catal. Today, 2006,
115, 33; (i) G. W. Coates and D. R. Moore, Angew. Chem., Int.
Ed., 2004, 43, 6618; ( j) D. J. Darensbourg and
M. W. Holtcamp, Coord. Chem. Rev., 2003, 103, 3857;
(k) X. L. Yin and J. R. Moss, Coord. Chem. Rev., 1999, 181, 27.
3 For recent reviews on chemical reaction in CO2, see:
(a) Chemical Synthesis Using Supercritical Fluids, ed.
P. D. Jessop and W. Leitner, Willy-VCH, Weinheim, 1999;
(b) P. D. Jessop, T. Ikariya and R. Noyori, Chem. Rev., 1999,
99, 475; (c) A. Baiker, Chem. Rev., 1999, 99, 453;
(d) W. Leitner, Top. Curr. Chem., 1999, 206, 107;
(e) P. Licence, J. Ke, M. Sokolova, S. K. Ross and
M. Poliakoff, Green Chem., 2003, 5, 99; (f) W. Keim, Green
Chem., 2003, 5, 105; (g) R. A. Sheldon, Green Chem., 2005, 7,
267; (h) Green Chemistry Using Liquid and Supercritical
Carbon Dioxide, ed. J. M. DeSimone and W. Tumas, Oxford
University Press, 2003; (i) E. J. Beckman, J. Supercrit. Fluids,
2004, 28, 121; ( j) P. G. Jessop, J. Supercrit. Fluids, 2006, 38,
211; (k) H. R. Hobbs and N. R. Thomas, Chem. Rev., 2007,
107, 2786; (l) P. Jessop and B. Subramaniam, Chem. Rev.,
2007, 107, 2666.
4-Chloromethyl-1,3-dioxolan-2-one (6e). 1H NMR (CDCl3,
400 MHz) δ 3.71 (dd, 3J = 3.2 Hz, 2J = 12.0 Hz, 1H, ClCH2), 3.80
(dd, 3J = 5.2 Hz, J = 12.0 Hz, 1H, ClCH2), 4.39 (dd, J = 6.0 Hz,
2J = 8.4 Hz, 1H, OCH2), 4.58 (t, 3J = 8.4 Hz, 1H, OCH2), 4.98 (m,
1H, CHO); 13C NMR (CDCl3, 100.6 MHz) δ 43.83, 66.84, 74.29,
154.28.
2
3
4-Isopropoxy-1,3-dioxolan-2-one (6e). 1H NMR (CDCl3,
400 MHz) δ 1.08 (t, 3J = 6.4 Hz, 6H, 2 × CH3), 3.62–3.51 (m, 3H,
(CH3)2CHO, (CH3)2CHOCH2), 4.30 (dd, 3J = 8.0 Hz, 2J = 15.6 Hz,
1H, OCH2), 4.42 (dd, J = 8.0 Hz, J = 15.6 Hz, 1H, OCH2), 4.74
(m, 1H, CHO); 13C NMR (CDCl3, 100.6 MHz) δ 21.52, 21.64,
66.15, 66.88, 72.58, 75.18, 155.02.
3
2
Conclusions
In summary, phosphonium chloride covalently bound to fluor-
ous polymers is proved to be an efficient and recyclable homo-
geneous CO2-soluble catalyst for solvent-free synthesis of cyclic
carbonate from propylene oxide and carbon dioxide under
supercritical conditions. Incorporation of the fluorinated
chain in the polymer effectively enhance the solubility of phos-
phonium salts which are usually insoluble in scCO2, thus pro-
viding a simple way for performing homogeneous catalysis
under scCO2 conditions. Furthermore, the catalyst can be
easily recovered upon releasing CO2 and is reusable for up to 7
cycles without significant loss of activity, while the selectivity
of propylene carbonate remained >99%.
4 (a) A.-A. G. Shaikh and S. Sivaram, Chem. Rev., 1996, 96, 951;
(b) M. Yoshida and M. Ihara, Chem.–Eur. J., 2004, 10, 2886;
(c) B. Schäffner, F. Schäffner, S. P. Verevkin and A. Börner,
Chem. Rev., 2010, 110, 4554.
5 For recent typical references on coupling of CO2 and epox-
ides catalyzed by homogeneous catalytic system, see:
(a) Z.-Z. Yang, Y.-N. Zhao, L.-N. He, J. Gao and Z.-S. Yin,
Green Chem., 2012, 14, 519; (b) Z.-Z. Yang, L.-N. He,
Y.-N. Zhao, B. Li and B. Yu, Energy Environ. Sci., 2011, 4,
3971; (c) Z.-Z. Yang, L.-N. He, C.-X. Miao and S. Chanfreau,
Adv. Synth. Catal., 2010, 352, 2233; (d) C.-X. Miao,
J.-Q. Wang, Y. Wu, Y. Du and L.-N. He, ChemSusChem, 2008,
1, 236; (e) A. Ghosh, P. Ramidi, S. Pulla, S. Z. Sullivan,
S. L. Collom, Y. Gartia, P. Munshi, A. S. Biris, B. C. Noll and
B. C. Berry, Catal. Lett., 2010, 137, 1; (f) J. Sun, L.-J. Han,
W.-G. Cheng, J.-Q. Wang, X.-P. Zhang and S.-J. Zhang, Chem-
SusChem, 2011, 4, 502; (g) F. Wu, X.-Y. Dou, L.-N. He and
C.-X. Miao, Lett. Org. Chem., 2010, 7, 73; (h) X.-Y. Dou,
J.-Q. Wang, Y. Du, E. Wang and L.-N. He, Synlett, 2007, 3058;
(i) L.-N. He, H. Yasuda and T. Sakakura, Green Chem., 2003,
5, 92; ( j) H. Yasuda, L.-N. He and T. Sakakura, J. Catal.,
2005, 233, 119; (k) R. L. Paddock and S. T. Nguyen, J. Am.
Chem. Soc., 2001, 123, 11498; (l) X.-B. Lu, B. Liang,
Y.-J. Zhang, Y.-Z. Tian, Y.-M. Wang, C.-X. Bai, H. Wang and
R. Zhang, J. Am. Chem. Soc., 2004, 126, 3732; (m) T. Aida and
S. Inoue, J. Am. Chem. Soc., 1983, 105, 1304; (n) H. S. Kim,
J. J. Kim, B. G. Lee, O. S. Jung, H. G. Jang and S. O. Kang,
Angew. Chem., Int. Ed., 2000, 39, 4096; (o) J.-S. Tian,
C.-X. Miao, J.-Q. Wang, F. Cai, Y. Du, Y. Zhao and L.-N. He,
Green Chem., 2007, 9, 566; (p) R. L. Paddock and
S. T. Nguyen, Chem. Commun., 2004, 1622; (q) V. Caló,
Acknowledgements
This work was partially supported by the National Science
Foundation of China (Grant 21172125).
Notes and references
1 For recent reviews on fixation of carbon dioxide, see:
(a) D. J. Darensbourg, R. M. Mackiewicz, A. L. Phelps and
D. R. Billodeaux, Acc. Chem. Res., 2004, 37, 836;
(b) P. Braunstein, D. Matt and D. Nobel, Chem. Rev., 1988,
88, 747; (c) 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. Paulvannanand and E. J. Sorensen,
Nature, 1994, 367, 630; (d) D. H. Gibson, Chem. Rev., 1996,
96, 2063; (e) W. Leitner, Coord. Chem. Rev., 1996, 153, 257.
2 For recent reviews on transformation of carbon dioxide, see:
(a) X.-B. Lu and D. J. Darensbourg, Chem. Soc. Rev., 2012, 41,
1462; (b) I. Omae, Coord. Chem. Rev., 2012, 256, 1384;
(c) M. Cokoja, C. Bruckmeier, B. Rieger, W. A. Herrmann
and F. E. Kühn, Angew. Chem., Int. Ed., 2011, 50, 8510;
(d) T. Sakakura and K. Kohno, Chem. Commun., 2009, 1312;
114 | Green Chem., 2013, 15, 110–115
This journal is © The Royal Society of Chemistry 2013

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Green Chemistry
Paper
A. Nacci, A. Monopoli and A. Fanizzi, Org. Lett., 2002, 4,
2561; (r) H. Kawanami, A. Sasaki, K. Matsui and
Y. Ikushima, Chem. Commun., 2003, 896; (s) Y. Du,
J.-Q. Wang, J.-Y. Chen, F. Cai, J.-S. Tian, D.-L. Kong and
L.-N. He, Tetrahedron Lett., 2006, 47, 1271.
Z.-F. Zhang, K.-L. Ding, B.-X. Han, Y. Xie, T. Jiang and
Z.-M. Liu, Chem.–Eur. J., 2007, 13, 6992; (s) K. Yamaguchi,
K. Ebitani, T. Yoshida, H. Yoshida and K. Kaneda, J. Am.
Chem. Soc., 1999, 121, 4526; (t) A.-L. Zhu, T. Jiang, B.-X. Han,
J.-C. Zhang, Y. Xie and X.-M. Ma, Green Chem., 2007, 9, 169;
(u) F. Shi, Q. Zhang, Y. Ma, Y. He and Y. Deng, J. Am. Chem.
Soc., 2005, 127, 4182.
6 For recent typical references on coupling of CO2 and epox-
ides catalyzed by heterogeneous catalytic system, see:
(a) J. Gao, Q.-W. Song, L.-N. He, C. Liu, Z.-Z. Yang, X. Han, 7 For the reactions based on tethering fluorinated chains to
X.-D. Li and Q.-C. Song, Tetrahedron, 2012, 68, 3835;
(b) J.-N. Lu and P. H. Toy, Synlett, 2011, 659; (c) H. C. Cho,
H. S. Lee, J. Chun, S. M. Lee, H. J. Kim and S. U. Son, Chem.
Commun., 2011, 47, 917; (d) I. Shibata, I. Mitani, A. Imakuni
and A. Baba, Tetrahedron Lett., 2011, 52, 721; (e) A. Buchard,
M. R. Kember, K. G. Sandeman and C. K. Williams, Chem.
Commun., 2011, 47, 212; (f) W.-L. Dai, L. Chen, S.-F. Yin,
S.-L. Luo and C.-T. Au, Catal. Lett., 2010, 135, 295;
(g) L.-P. Guo, C.-M. Wang, X.-Y. Luo, G.-K. Cui and H.-R. Li,
Chem. Commun., 2010, 46, 5960; (h) Y. Xie, K.-L. Ding,
Z.-M. Liu, J.-J. Li, G.-M. An, R.-T. Tao, Z.-Y. Sun and
Z.-Z. Yang, Chem.–Eur. J., 2010, 16, 6687; (i) Y. Tsutsumi,
K. Yamakawa, M. Yoshida, T. Ema and T. Sakai, Org. Lett.,
2010, 12, 5728; ( j) Y.-B. Xiong, H. Wang, R.-M. Wang,
Y.-F. Yan, B. Zheng and Y.-P. Wang, Chem. Commun., 2010,
46, 3399; (k) A. Decortes, M. M. Belmonte, J. B. Buchholz
and A. W. Kleij, Chem. Commun., 2010, 46, 4580; (l) C.-R. Qi,
J.-W. Ye, W. Zeng and H.-F. Jiang, Adv. Synth. Catal., 2010,
352, 1925; (m) X.-X. Zheng, S.-Z. Luo, L. Zhang and
catalysts in scCO2, see: (a) T. Sarbu, T. Styranec and
E. J. Beckman, Nature, 2000, 405, 165; (b) W. Leitner, Nature,
2000, 405, 129; (c) E. J. Beckman, Chem. Commun., 2004,
1885; (d) D. E. Bergbreiter, J. G. Franchina and B. L. Case,
Org. Lett., 2000, 2, 393; (e) K. Burgemeister, G. Francio,
H. Hugl and W. Leitner, Chem. Commun., 2005, 6026;
(f) D. J. Adams, J. A. Bennett, D. J. Cole-Hamilton,
E. G. Hope, J. Hopewell, J. Kight, P. Pogorzelec and
A. M. Stuart, Dalton Trans., 2005, 3862; (g) Y. Hu, W. Chen,
A. M. B. Osuna, J. A. Iggo and J. Xiao, Chem. Commun., 2002,
788; (h) W. Chen, Y. Hu and J. Xiao, Chem. Commun., 2000,
839; (i) I. Kani, M. A. Omary, M. A. Rawashdeh-Omary,
Z. K. Lopez-Castillo, R. Flores, A. Akgerman and J. P. Fackler,
Jr., Tetrahedron, 2002, 58, 3923; ( j) I. Kani, R. Flores,
J. P. Facler, Jr. and A. Akgerman, J. Supercrit. Fluids, 2004,
31, 287; (k) R. Flores, Z. K. Lopez-Castillo, I. Kani,
J. P. Facler, Jr. and A. Akgerman, Ind. Eng. Chem. Res., 2003,
42, 6720; (l) S. Kainz, Z. Y. Luo, D. P. Curran and W. Leitner,
Synthesis, 1998, 1425.
J.-P. Cheng, Green Chem., 2009, 11, 455; (n) J.-L. Song, 8 For the reaction of enantiomerically pure epoxides with CO2
Z.-F. Zhang, S.-Q. Hu, T.-B. Wu, T. Jiang and B.-X. Han,
Green Chem., 2009, 11, 1031; (o) Y. Kayaki, M. Yamamoto
and T. Ikariya, Angew. Chem., Int. Ed., 2009, 48, 4194;
(p) J.-Q. Wang, X.-D. Yue, F. Cai and L.-N. He, Catal.
Commun., 2007, 8, 167; (q) Y. Du, F. Cai, D.-L. Kong and
L.-N. He, Green Chem., 2005, 7, 518; (r) J.-L. He, T.-B. Wu,
yielding enantiomerically pure cyclic carbonates with com-
plete retention of the original stereochemistry, see:
(a) X.-B. Lu, Y.-J. Zhang, K. Jun, L.-M. Luo and H. Wang,
J. Catal., 2004, 227, 537; (b) R. L. Paddock, Y. Hiyama,
J. M. McKay and S. B. T. Nguyen, Tetrahedron Lett., 2004, 45,
2023.
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