Metal porphyrin/phenyltrimethylammonium tribromide: High efficient catalysts for coupling reaction of CO2 and epoxides

Article abstract of DOI:10.1016/j.molcata.2006.06.011

Novel and high efficient catalysts of metal porphyrin (M(TPP)X, M = Co, Fe, Ru, Mn; X = Cl^-, Br^-, OAc^-, OTs^-, Cl₃CCO₂^-)/phenyltrimethylammonium tribromide (PTAT) were developed t

Full text of DOI:10.1016/j.molcata.2006.06.011

Journal of Molecular Catalysis A: Chemical 261 (2007) 262–266
Metal porphyrin/phenyltrimethylammonium tribromide: High efficient
catalysts for coupling reaction of CO2 and epoxides
Lili Jin, Huanwang Jing∗, Tao Chang, Xiuli Bu, Li Wang, Zhongli Liu
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering,
Lanzhou University, 222 South Tianshui Road Lanzhou, Gansu 730000, P.R. China
Received 28 April 2006; accepted 2 June 2006
Available online 15 September 2006
Abstract
Novel and high efficient catalysts of metal porphyrin (M(TPP)X, M = Co, Fe, Ru, Mn; X = Cl−, Br−, OAc−, OTs−, Cl3CCO2−)/
phenyltrimethylammonium tribromide (PTAT) were developed to catalyze the coupling reaction of carbon dioxide and epoxides at room tem-
perature.
© 2006 Elsevier B.V. All rights reserved.
Keywords: Carbon dioxide; Epoxides; Metal porphyrin; Phenyltrimethylammonium tribromide; Coupling reaction
1. Introduction
ate from propylene oxide and carbon dioxide using the catalyst
system of Cr(TPP)Cl/DMAP operating under 780 psi of CO2 at
50 ◦C. Nguyen and co-authors [28] have reported the catalyst
system of Co(TPP)X/DMAP. Srinivas and co-authors [29] have
reported the catalyst system of Cu(II)porphyrin/DMAP. But the
coupling reaction must undergo at 120 ◦C. Therefore, the explo-
ration of highly efficient catalysts for coupling carbon dioxide
with epoxides under low temperature and pressure still remains
a challenging.
The chemistry of carbon dioxide have recently received much
attention from both an economical and an environmental point
of view: utilization of the least-expensive carbon source and
reduction of global-warming gas [1–6]. The cyclic carbonates
are one of products of carbon dioxide fixation and widely used
as organic synthetic intermediates, aprotic polar solvents, pre-
cursors for biomedical applications, and as raw materials for
engineering plastics [7–14]. Various catalysts including alkali
metal salts, Lewis acids, transition metal complexes, ionic liq-
uids, and organometallic compounds, have been developed for
these coupling reactions of CO2 with epoxides to yield carbon-
ates [15–23]. While the advances have been significant, most of
these catalysts currently suffer from low catalyst reactivity, the
need for co-solvent, or the requirement for high pressure and/or
high temperature. Very recently, bifunctional catalyst systems
of Co(Salen)X/Bu4NY [24–26] were found to be the most effi-
cient catalyst systems for this transformation. But, there are rare
reports about the Metal(TPP)X catalyst systems. Kruper and
Dellar [27] have reported the synthesis of propylene carbon-
Herein, we report our excellent results for investigating the
catalytic activity of new M(TPP)X/PTAT catalyst systems in the
coupling reaction of CO2 and epoxides.
2. Experimental
2.1. Materials
Propylene oxide was distilled from CaH2. Other epoxides
and PTAT were purchased from Aldrich and used to reaction
without further purification.
2.2. Porphyrins
∗
Free-base porphyrins H2TPP (5,10,15,20-tetraphenyl-
Corresponding author. Tel.: +86 931 891 2585; fax: +86 931 891 2582.
E-mail address: hwjing@lzu.edu.cn (H. Jing).
porphyrin) [30], H2TMPP (5,10,15,20-tetra-o-methoxyphenyl-
1381-1169/$ – see front matter © 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.molcata.2006.06.011

L. Jin et al. / Journal of Molecular Catalysis A: Chemical 261 (2007) 262–266
263
porphyrin) [31], H2TNPP (5,10,15,20-tetra-o-nitrophenylpo-
rphyrin), H2TAPP (5,10,15,20-tetra-o-aminophenylporphyrin)
[32], FeIII(TPP)Cl, MnIII(TPP)Cl [33,34], Ru(TPP)(PPh3)Cl
[35–37] were synthesized, purified and characterized following
the procedures of literatures described above.
2.3. Cobalt(II) porphyrins
Cobalt(II) porphyrins were obtained by metallation of free
base porphyrin with Co(OAc)·2H2O in DMF using the method
of literature [33]. The cobalt porphyrins were purified by
column chromatography of silica gel, using chloroform as
eluent.
Scheme 1.
Table 2
Anion effect of Co(TPP)X on the coupling reaction of propylene oxide and CO2
2.4. Cobalt(III) porphyrins
a
Entry Catalyst/co-catalyst
Time (h) Yield (%) TONb TOFc
To a suspended solution of CoII(TPP) complex (67.1 mg,
0.1 mmol) in 5 ml toluene, glacial acetic acid (0.14 ml, 2 mmol,
20 equiv.) was added. The solution was stirred at room tem-
perature for 4 h. The solvent and unreacted glacial acetic acid
were removed under reduced pressure to leave a reddish-brown
solid that was used to the oxirane–CO2 reaction as catalyst.
CoIII(TPP)Cl and CoIII(TPP)Br were prepared according to the
literature methods [38,39].
1
2
3
4
5
6
7
Co(TPP)(OAc)/PTAT
Co(TPP)Br/PTAT
Co(TPP)Cl/PTAT
4.6
4
93
93
930
930
930
560
900
662
620
202
233
186
80
5
93
Co(TPP)OTs/PTAT
7
56
Co(TPP)(O2CCCl3)/PTAT
Co(TPP)(O2CCCl3)/PTAT
Co(TPP)(OAc)/PTAT
3
1
1
90
66.2
62
300
662
620
a
Reaction condition: catalyst (0.1 mmol), co-catalyst (2 equiv.), propylene
oxide (7 ml, 100 mmol), CO2 (100 psi), T = 20 ◦C.
b
Moles of propylene carbonate produced per mole of catalyst.
Moles of propylene carbonate produced per mole of catalyst per hour.
2.5. General procedure of coupling reaction of CO2 and
epoxide
c
All coupling reactions were performed in a 250 ml stainless
steel autoclave equipped with a magnetic stir bar. As a typical
procedure, the autoclave reactor was successively charged
with CoIII(TPP)X (0.1 mmol), PTAT (75.2 mg, 0.2 mmol) and
propylene oxide (7 ml, 100 mmol) without additional solvent
unless mentioned otherwise. The reactor was pressurized
with CO2 to 100 psi, stirred at ambient temperature. After
the expiration of the desired time, the reactor was vented.
The remained mixture was distilled under reduced pres-
sure or recrystallized with ethanol to obtain the pure cyclic
carbonate.
3. Results and discussion
3.1. The effect of co-catalyst for Co(TPP)X on synthesis of
propylene carbonate
Taking notice of Lu’s results of catalyst system of
Co(Salen)X/Bu4NBr, TBAB was firstly chosen as a co-
catalyst instead of DMAP in Nguyen’s catalyst system
Co(TPP)X/DMAP. But the results show that the combination
of bifunctional catalyst system is not efficient (Table 1, entries
1 and 5) comparing to the Lu’s results (entries 6 and 7). Fortu-
nately, when the phenyltrimethyl ammonium tribromide (PTAT)
was used as a co-catalyst, the new bifunctional catalyst system
Co(TPP)X/PTAT demonstrated an excellent catalytic ability on
Table 1
a
Effect of co-catalyst in the coupling reaction of propylene oxide and CO2
Entry Catalyst
Co-catalyst Time (h) Yield (%) TOF (h−1
)
Table 3
1
Co(TPP)Cl
Co(TPP)Cl
Co(TPP)Cl
Co(TPP)(OAc)
Co(TPP)(OAc)
Co(Salen)Cl
Bu4NBr
DMAP
PTAT
PTAT
Bu4NBr
Bu4NBr
4
1
3
3
5
4
2.5
69.5
99
88
174
248
293
300
51
2b
3
Framework effect of porphyrins in the coupling reaction of propylene oxide and
a
CO2
4
90
Entry
Catalyst/co-catalyst
Time (h)
Yield (%)
TON
TOF
5
6c
7c
25.7
48.2
52.4
1
2
3
4
5
Co(TPP)(OAc)/PTAT
Co(TMPP)(OAc)/PTAT
Co(TNPP)(OAc)/PTAT
Co(TAPP)(OAc)/PTAT
Co(TPP)(OAc)/PTAT
3
3
3
3
4
90
85
34
31.5
20b
900
850
340
315
200
300
283
113
105
50
120
210
Co(Salen)(OAc) Bu4NBr
a
Reaction condition: catalyst (0.1 mmol), co-catalyst (2 equiv.), propylene
oxide (100 mmol, 7 ml), CO2 (100 psi), T = 25 ◦C.
b
Reference [28]: catalyst (0.4% mmol), co-catalyst (2 equiv.), propylene
a
oxide(1 ml), CO2 (100 psi), T = 120 ◦C.
Reaction condition: catalyst (0.1 mmol), PTAT (2 equiv.), propylene oxide
(100 mmol, 7 ml), CO2 (100 psi), T = 25 ◦C.
c
Reference [25]: catalyst (0.5 mmol), co-catalyst (1 equiv.), propylene oxide
b
(500 mmol, 35 ml), T = 25 ◦C.
Pressure of CO2: 15 psi.

264
L. Jin et al. / Journal of Molecular Catalysis A: Chemical 261 (2007) 262–266
Table 4
3.2. The anion effect of Co(TPP)X on synthesis of
propylene carbonate
Metal effect of catalysts on the coupling reaction of CO2 and propylene oxide
Entry
Catalyst
Time (h)
Yield (%)
TON
TOF
To select well catalyst system of Co(TPP)X/PTAT, various
cobalt(III) porphyrins (Scheme 1) with different counterions
were screened for the coupling reaction of CO2 and propylene
oxide (PO). The results are listed in Table 2. It can be seen that
all catalyst systems using different anions exhibit high catalytic
activity. Among these catalysts, 1e (Co(TPP)(Cl3CCO2))
exhibits higher catalytic activity than the others used in
this study. The activity order is about 1e > 1b > 1a > 1c > 1d.
However, the activity of 1d (Co(TPP)OTs) is lower due to its
bulkiness and high electron-withdrawing ability. The propylene
carbonate was obtained with high TOF (entries 6 and 7) and
1
2
3
4
Co(TPP)Cl/PTAT
Mn(TPP)Cl/PTAT
Fe(TPP)Cl/PTAT
3
3
3
3
88
27
10
14
880
270
98
293
90
33
Ru(TPP)(PPh3)Cl/PTAT
140
46
aReaction condition: catalyst (0.1 mmol), PTAT (2 equiv.), propylene oxide
(100 mmol, 7 ml), CO2 (100 psi), T = 25 ◦C.
synthesis of propylene carbonate at room temperature (entries
3 and 4). These can−be explained that the easier leaving group
of neucleophile Br3 of PTAT has higher activity than that of
neucleophile Br− of TBAB.
Table 5
The coupling results of CO2 and various epoxides catalyzed by Co(TPP)(OAc)/PTATa
Entry
Substrate (R=)
Time (h)
Product
Yieldb (%)
93
1
CH3
4.6
2
CH2Cl
7.5
7
57
3c
(CH2)9CH3
68.1
4
3
5
34.1
96
5d
CH2OPh
6
Ph
10
20
71
7d
5
a
Reaction conditions: Co(TPP)(OAc) (0.1 mmol), PTAT (75.2 mg, 0.20 mmol), epoxide (100 mmol), CO2 (100 psi), T = 20 ◦C.
Isolated yield.
Ten milliliter DMF as solvent.
Twenty milliliter acetone was used to dilute the substrate.
b
c
d

L. Jin et al. / Journal of Molecular Catalysis A: Chemical 261 (2007) 262–266
265
was obtained with high yield by prolonging the reaction time
(entries 1 and 5) using 1a or 1e as catalyst.
can be easily introduced into organic molecules at room
temperature.
3.3. The framework effect of Co(TPP)X on synthesis of
propylene carbonate
Acknowledgments
We are grateful for the financial support of the Natural Sci-
ence Foundation of China (NSFC QT 20021001) and Natural
Science Foundation of Gansu Province (3ZS041-A25-008).
Porphyrins with different framework were investigated on
this coupling reaction of PO and CO2 (Scheme 1). From the
results shown in Table 3, we found that substituted groups in the
framework of porphyrin influenced the CO2 insertion reaction.
When the catalysts bearing electron-withdrawing groups (1g) or
electron-donating groups (1f and 1h), they tend to give dimin-
ished TOF (Table 3, entries 2–4). This is attributed to the steric
effect of substituted groups. We also explored the influence of
CO2 pressure. When the CO2 pressure was reduced from 100
to 15 psi, propylene carbonate was only obtained with 20%
yield (Table 3, entry 5). The concentration of CO2 in propylene
oxide will be reduced when decreased the pressure resulting
in low catalytic activity. This is consistent with literature result
[28].
References
[1] D.J. Darensbourg, R.M. Mackiewicz, A.L. Phelps, D.R. Billodeaux, Acc.
Chem. Res. 37 (2004) 836.
[2] D.J. Darensbourg, M.W. Holtcamp, Coord. Chem. Rev. 153 (1996)
155.
[3] D.R. Moore, M. Cheng, E.B. Lobkovsky, G.W. Coates, Angew. Chem. Int.
Ed. 41 (2002) 2599.
[4] 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, E.J. Sorensen,
Nature 367 (1994) 630.
[5] T. Takata, Y. Furusho, K.-I. Murakawa, T. Endo, H. Matsuoka, T. Hirasa,
J. Matsuo, M. Sisido, J. Am. Chem. Soc. 120 (1998) 4530.
[6] H.-T. Chang, K.B. Sharpless, Tetrahedron Lett. 37 (1996) 3219.
[7] N. Takeda, S. Inoue, Bull. Chem. Soc. Jpn. 51 (1978) 3564.
[8] N. Takeda, S. Inoue, Macromol. Chem. 179 (1978) 1377.
[9] T. Aida, Macromolecules 15 (1982) 682.
3.4. The metal effect of M(TPP)X on synthesis of propylene
carbonate
[10] T. Aida, M. Ishikawa, S. Inoue, Macromolecules 19 (1986) 8.
[11] J.H. Jung, M. REE, T. Chang, J. Polym. Sci. Part A: Polym. Chem. 37
(1999) 3329.
[12] T. Aida, S. Inoue, J. Am. Chem. Soc. 105 (1983) 1304.
[13] S. Mang, A.I. Cooper, M.E. Colclough, N. Chauhan, A.B. Holmes, Macro-
molecules 33 (2000) 303.
[14] L.M. Stamp, S.A. Mang, A.B. Holmes, K.A. Kinghts, Y.R. de Miguel, I.F.
McConvey, Chem. Commun. (2001) 2502.
[15] A. Baba, T. Nozaka, H. Matsuda, Bull. Chem. Soc. Jpn. 60 (1987)
1552.
Besides these condition screenings, we also selected different
metals as a Lewis acidic center and investigated the catalytic
activity of M(TPP)Cl/PTAT in the coupling reaction of CO2
and propylene oxide (Table 4). It can be seen that the catalytic
activity was in the order of Co > Mn > Ru > Fe. From the results
mentioned above, we concluded that Co(TPP)(Cl)/PTAT system
has higher catalytic activity.
[16] F. Li, C. Xia, F. Xu, W. Sun, G. Chen, Chem. Commun. (2003)
2042.
[17] R.L. Paddock, S.T. Nguyen, J. Am. Chem. Soc. 123 (2001) 11498.
[18] Y. Deng, J. Peng, New J. Chem. 25 (2001) 639.
[19] V. Calo´, A. Nacci, A. Monopoli, A. Fanizzi, Org. Lett. 4 (2002)
2561.
[20] X. Lu, X. Feng, R. He, Appl. Catal. Part A: Gen. 234 (2002) 25.
[21] W.N. Sit, S.M. Ng, K.Y. Kwong, C.P. Lau, J. Org. Chem. 70 (2005)
8583.
[22] J.-L. Jiang, F. Gao, R. Hua, X. Qiu, J. Org. Chem. 70 (2005) 381.
[23] H.B. Xie, S.H. Li, S.B. Zhang, J. Mol. Catal. A: Chem. 250 (2006) 30.
[24] X.-B. Lu, Y.-J. Zhang, K. Jin, L.-M. Luo, H. Wang, J. Catal. 227 (2004)
537.
[25] 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.
[26] X.-B. Lu, Y.-J. Zhang, B. Liang, X. Li, H. Wang, J. Mol. Catal. A: Chem.
210 (2004) 31.
[27] W.J. Kruper, D.V. Dellar, J. Org. Chem. 60 (1995) 725.
[28] R.L. Paddock, Y. Hiyama, J.M. McKay, S.T. Nguyen, Tetrahedron Lett. 45
(2004) 2023.
3.5. The cyclic carbonate synthesis from CO2 with various
epoxides catalyzed by Co(TPP)(OAc)/PTAT
Under the optimized reaction condition, we examined the
reactions of other terminal epoxides with carbon dioxide.
The results are summarized in Table 5. Co(TPP)(OAc)/PTAT
was found to be active to other terminal epoxides, producing
the responding cyclic carbonates with high yield and TOF.
However, styrene oxide seemed to give relatively low activity
(entry 6) due to precipitation of solid product. In comparison
with that, the phenoxypropylene oxide (entry 5) and the
cyclohexenyl-(1,1ꢀ-bisglycidyl)-4,5-dicarboxylic ester (entry
7) were took the coupling reaction with some dilute solvent
respectively. To a solution of dodecene oxide, some diluter DMF
was added for reducing the viscousness and enhancing the yield
(entry 3).
[29] R. Srivastsva, T.H. Bennur, D. Srinivas, J. Mol. Catal. A: Chem. 226 (2005)
199.
4. Conclusions
[30] A.D. Adler, F.R. Longo, J.D. Finarelli, J. Goldmacher, J. Assoup, L. Kor-
sakoff, J. Org. Chem. 32 (1967) 476.
[31] E. Tsuchida, T. Komatsu, E. Hasegawa, H. Nishide, J. Chem. Soc. Dalton
Trans. 9 (1990) 2713.
[32] J.P. Collman, J. Am. Chem. Soc. 97 (1975) 1427.
[33] A.D. Alder, F.R. Long, F. Kampas, J. Kim, J. Inorg. Nucl. Chem. 32 (1970)
2443.
In summary, we developed a series of novel and high
efficient bifunctional catalysts, M(TPP)X/PTAT, in which
Co(TPP)(OAc)/PTAT is one of the best catalyst system for
the coupling reaction of carbon dioxide and various epoxides
yielding relevant cyclic carbonates by which carbon dioxide

266
L. Jin et al. / Journal of Molecular Catalysis A: Chemical 261 (2007) 262–266
[34] R.D. Jones, D.A. Summerville, F. Basolo, J. Am. Chem. Soc. 100 (1978)
4416.
[37] B.R. James, D. Dolphin, T.W. Leung, Can. J. Chem. 62 (1984)
1238.
[35] J.P. Collman, C.E. Barnes, P.J. Brothers, T.J. Collins, T. Ozawa, J.C. Gal-
lucci, J.A. Ibers, J. Am. Chem. Soc. 106 (1984) 5151.
[36] S. Apiel, D. Dolphin, G. Domazetis, B.R. James, T.W. Leung, S.J. Rettig,
J. Trotter, G.M. Willams, Can. J. Chem. 62 (1984) 755.
[38] T. Sakurai, K. Yamamoto, H. Naito, N. Nakamoto, Bull. Chem. Soc. Jpn.
49 (1976) 3042.
[39] A.K.-S. Tse, K.W. Mak, K.S. Chan, Organometallics 17 (1998)
2651.