Effective scCO2-ionic liquid reaction system based on symmetric aliphatic ammonium salts for the rapid CO2 fixation with aziridine to 2-oxazolidinone

Article abstract of DOI:10.1246/cl.2005.60

The hybrid reaction system composed of supercritical carbon dioxide and room temperature ionic liquid based on symmetric tetraalkyl ammonium salts can effectively promote the carbon dioxide fixation from aziridine to 2-oxazolidinone in the presence of iod

Full text of DOI:10.1246/cl.2005.60

6
0
Chemistry Letters Vol.34, No.1 (2005)
Effective scCO -ionic Liquid Reaction System Based on Symmetric Aliphatic Ammonium Salts
2
for the Rapid CO Fixation with Aziridine to 2-Oxazolidinone
2
ꢀ
y
Hajime Kawanami, Hajime Matsumoto, and Yutaka Ikushima
Supercritical Fluid Research Center, National Institute of Advanced Science and Technology, and CREST,
Japan Science and Technology, 4-2-1, Nigatake, Miyagino-ku, Sendai 983-8551
y
Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Science and Technology,
-8-31 Midorigaoka, Ikeda, Osaka 563-8577
1
(Received October 4, 2004; CL-041165)
The hybrid reaction system composed of supercritical car-
bon dioxide and room temperature ionic liquid based on sym-
metric tetraalkyl ammonium salts can effectively promote the
carbon dioxide fixation from aziridine to 2-oxazolidinone in
the presence of iodine in high yield of 98% within 5 min. The
TOF value under this condition is 254 times larger than that us-
ing conventional organic solvent.
‘‘green solvent.’’ IL has a lot of advantages regarding environ-
2
mental managements of the chemical synthesis. However, IL
has a fatal disadvantage for the difficultly in the separation of or-
ganic products and IL. To overcome the troublesome product-
solvent separation, scCO2–IL hybrid system was introduced as
3
a greener system. This system can also be applied for the reac-
4
tion such as the hydrogeneration of styrene, the Beckman rear-
5
rangement of cyclohexanone oxime, and recently, we have re-
ported the successful achievement of the rapid synthesis of cy-
clic carbonate using this hybrid reaction system based on imida-
From the standpoint of the environment protection, the de-
velopment of production processes using chemical fixation of
carbon dioxide (CO2) has been drawing much interest in indus-
trial chemistry and biotechnology, because there are numerous
possibilities that CO2 can be used as a safe and cheap C1 raw
material to produce useful organic compounds. Supercritical car-
bon dioxide (scCO2) possesses many advantageous properties
such as tunable solubility, faster mass transfer than conventional
organic solvent, controllability of reactions by pressure, and
temperature manipulation. However, the CO2 chemical fixation
under scCO2 conditions often needs longer reaction times ex-
tending to several hours to obtaine satisfactory results so far, be-
6
zolium salts.
In this paper, we have first applied the scCO2–IL reaction
system based on the tetraalkyl ammonium salts into the reaction
of carbon dioxide with aziridine 1 into 2-oxazolidinone 2
(Scheme 1) to develop the various swift chemical fixation of
CO2, since the ILs are electrochemically more stable than that
Me
IL =
R
N
R
SO2CF3
Me
scCO2-IL
Cat.: I2
N
R
R
HN
O
SO CF
2
3
N
H
R = nC8H17
O
2
1
[TOA]+
[TFSI]-
cause of the inert property.
Recently, growing interest has been manifested in the use of
room temperature ionic liquid (IL), which has been considered
etc.
1
Scheme 1.
Table 1. The carbon dixoide fixation from aziridine to 2-oxazolidinone under scCO2-IL reaction system based on tetraalkyl ammo-
nium salts
Reaction time
/
Pressure
/ MPa
Reaction temp.
ꢁ
Yield of 2
/ %
Select. of 2
/ %
TOF
ꢂ1
Run
Reaction system
min
/ C
/ h
þ
þ
ꢂ
ꢂ
1
2
5
5
10
10
40
40
[EMIM] [BF4]
scCO2
scCO2
0
16
0
97
0
131
[EMIM] [TFSI]
þ
ꢂa
ꢂ
ꢂ
3
4
5
5
5
5
10
10
10
40
40
40
[TOA] [TFSI]
þ
scCO2
scCO2
scCO2
98
98
98
100
99
98
838
838
838
[TOA] [TFSI]
þ
[TOA] [TFSI]
þ
ꢂ
ꢂ
ꢂ
6
7
8
15
30
60
10
10
10
40
40
40
[TOA] [TFSI]
þ
scCO2
scCO2
scCO2
97
98
57
99
100
57
829
838
838
[TOA] [TFSI]
þ
b
[TOA] [TFSI]
þ
ꢂc
ꢂd
9
0
5
5
10
10
40
40
[TDA] [TFSI]
þ
scCO2
scCO2
89
86
97
98
761
735
1
[TDA] [TSAC]
þ
þ
ꢂ
ꢂ
ꢂ
11
12
13
5
5
5
2
8
14
40
40
40
[TOA] [TFSI]
[TOA] [TFSI]
CO2
scCO2
scCO2
2
64
57
98
99
98
17
547
487
þ
[TOA] [TFSI]
1
1
4
5
360
1260
11.8
6.9
40
80
ꢂ
Ethanol
Ethanol
scCO2
CO2
72
44
72
—e
7.2
3.3
a
b
c
d
e
þ
[
TOA] is tetraoctyl ammonium cation, and [TFSI] is bis(trifluoromethylsulfonyl)imide anion.
Aziridine 1 was not recovered, and unknown complex mixtures were formed.
þ
[
TDA] is tetradecyl ammonium cation.
ꢂ
[TSAC] is (2,2,2-trifluoro-N-(trifluoromethylsulfonyl)acetamide anion.
When methanol was used as a solvent, the selectivity was 70% in Ref. 12c.
Copyright Ó 2005 The Chemical Society of Japan

Chemistry Letters Vol.34, No.1 (2005)
61
9
a
based on imidazolium salts. The derivertives of 2-oxazolidi-
7
dioxide fixation from aziridine 1 to 2-oxazolidinone 2. It can
successfully derive the rapid reaction with 98% yield within
5 min. Furtheremore, the TOF values under this reaction system
are 116 times larger than that of the scCO2 reaction system and
254 times larger than that of the conventional organic solvents.
none 2 have been widely used in organic synthesis as chiral aux-
8
iliaries or building blocks for a variety of bioactive compounds.
We found that the tetraalkyl anmmonium salts with bis(trifluo-
9
romethylsulfonyl)imide cation is more effective for the
chemical fixation than imidazolium salts.
The model reaction of CO2 fixation from 2-methylaziridine
to 4-methyl-2-oxazolidinone 2 in the presence of iodine as a
This research was partly supported by Industrial Technology
Research Grant Program in ’03 from NEDO of Japan, and the
Ministry of Education, Culture, Sports, Science and Technology,
a Grant-in-Aid for Young Scientists (B), 16760619, 2004.
1
Lewis acid catalyst was conducted in a batch wise operation
under scCO2–IL reaction system with imidazolium salts or
tetraalkyl ammonium salts in which iodine can be dissolved.
1
0
References and Notes
1
The results were summarized in Table 1. Preliminary, 1-
þ
ꢂ
‘‘Chemical Synthesis Using Supercritical Fluids,’’ ed. by P. G.
Jessop and W. Leitner, Wiley-VCH, Weinheim (1999).
ethyl-3-methylimidazolium tetrafluoroborate([EMIM] [BF4] )
and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)-
2
a) ‘‘Ionic Liquid – Industrial Applications to Green Chemistry,’’
ACS Symposium Series 818, ed. by R. D. Roger and K. R. Seddon,
American Chemical Society, Washington, D. C. (2002). b) ‘‘Ionic
liquids in Synthesis,’’ ed. by P. Wasserscheid and T. Welton,
Wiley-VCH, Weinheim (2003). c) ‘‘Ionic Liquids as Green
Solvents,’’ ACS Symposium Series 856, ed. by R. D. Rogers and
K. R. Seddon, American Chemical Society, Washington, D.C.
þ
ꢂ
imide ([EMIM] [TFSI] ) were used as a scCO2–IL reaction
system (Runs 1 and 2) for carbon dioxide fixation with aziridine
1
, but 4-methyl-2-oxazolidinone 2 was obtained in a very poor
yield.
To attaine the better yield, over 80% in a shorter reaction
time, we applied the IL based on the tetraalkylammonium salts
for the scCO2–IL reaction system. When the tetraoctylammoni-
(2003).
þ
ꢂ
3
4
a) L. A. Blanchard, D. Hancu, E. J. Beckmann, and J. F. Brennecke,
Nature, 399, 28 (1999). b) L. A. Blanchard and J. F. Brennecke,
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and P. G. Jessop, J. Am. Chem. Soc., 123, 1254 (2001). b) D. J.
Heldebrandt and P. G. Jessop, J. Am. Chem. Soc., 125, 5600 (2003).
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um bis(trifluoromethanesulfonyl)imide([TOA] [TFSI] ) is
used, it is quite note worthy that the excellent yield of 98%
ꢁ
was obtained within 5 min and at the low temperature of 40 C
(
Run 3). The same reaction in ethanol at the temperature of
7a
ꢁ
80 C gave the lower yield of 44% for 21 h (Run 15), and in
ethanol–scCO2 at 40 C, the yield was 72% for 6 h (Run 14).
ꢁ
11
5
6
7
Furthermore, the turnover frequency (TOF) at 10 MPa (Run 3)
ꢂ1
H. Kawanami, A. Sasaki, K. Matsui, and Y. Ikushima, Chem.
Commun., 2003, 896.
is 838 h , which is 116 times faster than that in previous report
under the scCO2 reaction system with ethanol as co-solvent (Run
a) K. Soga, S. Hosoda, H. Nakamura, and S. Ikeda, Chem. Com-
mun., 1976, 617. b) H. Matsuda, A. Ninagawa, and H. Hasegawa,
Bull. Chem. Soc. Jpn., 58, 2717 (1985). c) T. Nomura, T. Nakano,
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K. G. Hodgson, and D. E. Thomson, J. Chem. Soc., Perkin Trans.
1, 1991, 961. e) P. Tascedda and E. Dunach, Chem. Commun.,
11
1
4), and surprisingly 254 times larger than that in conventional
7
a
organic solvent (Run 15). Besides, the IL can be used for
recycling of the scCO2–IL reaction system (Runs 4 and 5).
Though this scCO2–IL reaction system yields the excellent
productivity even at shorter reaction time, unknown reactions,
which might be the polymerization, occurred after longer reac-
2000, 449. f) T. H. Matthew and A. R. Pinhas, Tetrahedron Lett.,
44, 5457 (2003).
a) D. A. Evans, J. Bartroli, and T. L. Shih, J. Am. Chem. Soc., 103,
tion time leading to the decreasing of the yield of oxazolidinone
(
The pressure dependence of the yield of 2 was further inves-
tigated at 2, 8, 10, and 14 MPa (Runs 3 and 11–13), and an inter-
esting pressure dependence was observed. The yield increases
with increasing pressure, reaching a maximum yield at around
Runs 3 and 6–8).1
a,12
8
9
2
127 (1981). b) D. J. Ager, I. Prakash, and D. R. Schaad, Chem.
Rev., 96, 835 (1996). c) D. Tanner, Angew. Chem., Int. Ed. Engl.,
3, 599 (1994).
3
a) H. Matsumoto, M. Yanagida, K. Tanimoto, M. Nomura, Y.
Kitagawa, and Y. Miyazaki, Chem. Lett., 2000, 922. b) H.
Matsumoto, H. Kageyama, and Y. Miyazaki, Chem. Lett., 2001,
1
1
0 MPa, and then decreases with increasing pressure up to
4 MPa. In the range of atmospheric pressure to 14 MPa, two
1
2
82. c) Z.-B. Zhou, H. Matsumoto, and K. Tatsumi, Chem. Lett.,
004, 886.
phases consisted of CO2 and IL phase can be seen, and in the
low pressure range below 10 MPa, CO2 would dissolve into IL
phase, and the concentration of CO2 in the IL phase is increased
with increasing pressure, which, in turn, would increase the re-
action rate. Furthermore, the CO2 phase is transformed into
the supercritical state over 8 MPa, and so, a mass transfer of
product from IL phase to the scCO2 phase expected to be accel-
erated, resulting in the excellent yield.
1
0 The typical experimental procedure is as follows: propylene imine
3.0 mmol), iodine (0.1 mmol), and ionic liquid (1.0 mL) were
(
3
ꢁ
charged into a 25-cm reactor at 40 C, and CO2 was introduced in-
to the reactor using a high-pressure liquid pump and compressed to
the desired pressure within 5 min. The reactions were started by
stirring the mixture, continued for 5 min. After reaction, the reactor
ꢁ
was cooled to 0 C with ice and the pressure was released slowly. 2-
At the higher pressure of 10 MPa, 1 can be dissolved in the
CO2 phase from the IL phase, resulting the decreased mole frac-
tion of substrate 1 in the IL phase. Then the substrate 1 which is
in the CO2 phase would not transformed into 2 anymore. There-
fore, the yield is decreased at the higher pressures above 10 MPa.
In conclusion, we found that the hybrid reaction system con-
sisted of scCO2–symmetric aliphatic ammonium salts was more
suitable than that of scCO2–imidazolium salts for the carbon
Oxazolidinone was purified from the crude products by distillation
and was analyzed by NMR. The yields of the product were deter-
mined by GC–MS.
1 H. Kawanami and Y. Ikushima, Tetrahedron Lett., 43, 3841 (2002).
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and T. Ikariya, Angew. Chem., Int. Ed., Engl., 43, 717 (2004).
1
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Published on the web (Advance View) December 11, 2004; DOI 10.1246/cl.2005.60