Selective formation of trimethylene carbonate (TMC): Atmospheric pressure Carbon dioxide utilization

Article abstract of DOI:10.1002/ejoc.201403385

Carbon dioxide utilisation (CDU) is currently gaining increased interest due to the abundance of CO₂ and its possible application as a C₁ building block. We herein report the first example of atmospheric pressure carbon dioxide incorporation into oxetane to selectively form trimethylene carbonate (TMC), which is a significant challenge as TMC is thermodynamically less favoured than its corresponding co-polymer.

Full text of DOI:10.1002/ejoc.201403385

SHORT COMMUNICATION
DOI: 10.1002/ejoc.201403385
Selective Formation of Trimethylene Carbonate (TMC): Atmospheric Pressure
Carbon Dioxide Utilization
[a]
[a]
[a]
Benjamin R. Buckley,* Anish P. Patel, and K. G. Upul Wijayantha*
Keywords: Carbon dioxide utilization / Copper / Electrochemistry / Synthetic methods / Small ring systems
Carbon dioxide utilisation (CDU) is currently gaining in-
creased interest due to the abundance of CO and its possible
application as a C building block. We herein report the first
tion into oxetane to selectively form trimethylene carbonate
(TMC), which is a significant challenge as TMC is thermody-
namically less favoured than its corresponding co-polymer.
2
1
example of atmospheric pressure carbon dioxide incorpora-
Introduction
from these reactions. For example, North and co-workers
have employed bimetallic aluminium salen complexes incor-
porating an ammonium bromide co-catalyst to prepare
cyclic carbonates in good yield from not only highly puri-
fied carbon dioxide but also directly from a fossil fuel power
station stack by use of a supported salen catalyst and flow
Anticipated pressures on fossil fuel resources in the com-
ing decades mean that raw materials for the chemical indus-
try must be found that can reduce our reliance on fossil-
fuel-based feedstocks.[1] Hence, the development of new
production processes for chemical syntheses from renewable
resources is a challenge that should be a priority for all
[4]
reactor. These reactions take place at mild temperatures
and atmospheric pressures. Interestingly, structurally re-
lated salen-based catalysts have been successful in the corre-
sponding polycarbonate process, for example Darensbourg
[
2]
major economies. Research into/application of carbon di-
oxide utilization (CDU) technologies has recently gained
[
3]
increased interest. CDU offers an attractive alternative to
the well-established carbon dioxide storage (CCS) pro-
cesses, however, scale of production means that CDU is un-
likely to significantly reduce anthropogenic carbon dioxide
emissions, but waste carbon dioxide under CDU protocols
can be converted into useful chemicals or fuels.
[5]
and co-workers have reported several studies employing a
chromium-based salen complex to afford a range of poly-
carbonates; as have Lee and co-workers who have employed
[6]
salen–cobalt catalysts. Other catalytic systems have also
[7]
been successfully employed by both Coates and more re-
[8]
cently Williams, who has developed a series of highly
Carbon dioxide is abundant, cheap and non-toxic when
compared with other C building blocks, such as phosgene,
active bimetallic catalysts that are able to perform the poly-
merisation reactions with atmospheric pressure carbon di-
oxide. Decortes and Kleij have also reported atmosperice
1
and has been used in the manufacture of salicylic acid, urea
and cyclic carbonates for 50–100 years. However, because
of the relative inertness of carbon dioxide these processes
are significantly energy demanding with reactions taking
place at high temperatures and pressures. Therefore, if CDU
technologies are to become viable processes reliance on very
little energy input is required, hence processes at mild tem-
peratures (Ͻ 100 °C) and atmospheric pressures should be
targeted.
The insertion of carbon dioxide into epoxides to afford
either five-membered ring cyclic carbonates or the corre-
sponding polycarbonate has attracted considerable atten-
tion due to the industrial application of the products arising
pressure CO insertion to form five-membered ring carb-
2
[9]
onates using zinc–salophen catalysts.
Far less exposure has been given to carbon dioxide inser-
tion into other heterocyclic ring systems, mainly due to the
requirement for a high-energy substrate such as an epoxide
for the insertion to be favourable. One possible product
from carbon dioxide insertion into the challenging four-
membered ring analogue of epoxides, oxetanes, would be
the synthesis of six-membered ring cyclic carbonates or
polycarbonates. Trimethylene carbonate (TMC) 1 is a useful
monomer for ring-opening polymerization, as complete re-
tention of carbon dioxide is observed when polymerized to
[
10]
2
using a metal or non-metal catalyst (Scheme 1). These
[
a] Department of Chemistry, Loughborough University,
Loughborough, Leicestershire, LE11 3TU, UK
E-mail: b.r.buckley@lboro.ac.uk
polymers are of significant value since they are bio-
degradable and can be used in a range of medical devices.[
Traditionally TMC 1 has been prepared from 1,3-pro-
panediol and the highly poisonous phosgene gas, however,
more recently several greener alternatives have arisen, for
11]
u.wijayantha@lboro.ac.uk
http://brbuckley.wix.com/the-buckley-group
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201403385.
474
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 474–478

Formation of Trimethylene Carbonate: Carbon Dioxide Utilization
Results and Discussion
We started our investigation by applying our previously
reported optimized conditions for the synthesis of five-
membered ring cyclic carbonates from carbon dioxide and
[
18]
epoxides.
Gratifyingly, this resulted in the selective syn-
thesis of TMC 1 from trimethylene oxide 3, and under these
reaction conditions we did not observe the thermodynami-
cally more stable co-polymer 2. However, compound 1 was
only formed in a disappointing 40% yield (Table 1, Entry
Scheme 1. Traditional approaches to TMC 1 and poly(TMC) 2.
12), a range of electrode materials were then screened in an
attempt to enhance the isolated yield observed but this pro-
cess proved fruitless.
example transesterification employing 1,3-propanediol and
a dialkylcarbonate (Scheme 1).[ An attractive approach
would be to use carbon dioxide, which has previously been
employed to prepare five-membered ring cyclic carbonates
[19]
12]
Table 1. Optimization studies for the production of TMC 1 from
from epoxides, however, selective formation of TMC 1 trimethylene oxide 3.[
using carbon dioxide is a non-trivial process as it is thermo-
a]
dynamically less stable than its corresponding co-polymer
2, thus selective production of the monomer presents a
significant challenge.
Baba and co-workers were the first to report the ring
expansion of oxetanes with carbon dioxide to afford six-
membered cyclic carbonates, they employed stibonium
[
13]
[14]
iodide
or organotin iodide/nBu PO
catalysts at typi-
Ratio[b]
1/2
Yield[c]
1 [%]
3
Entry Supporting
Electrolyte
Temp.
[°C]
Current
[mA]
cally 100 °C and 49 atmospheres of carbon dioxide. Re-
cently Darensbourg has shown that trimethylene carbonate
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
Bu
Bu NI
4
NBr
25
25
25
25
25
25
25
25
25
25
50
50
75
75
75
75
75
75
60
60
60
60
60
60
60
30
90
120
60
60
0
Ͼ 99:1
Ͼ 99:1
–
25
50
Ͻ 5
Ͻ 5
1
can be obtained from trimethylene oxide 3, VO(acac)2/
4
nBu NBr at 60 °C under 35 atmospheres of carbon dioxide
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Bu
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
NCl
NPF
NI
NI
NI
NI
NI
NI
NI
NBr
NBr
NI
NI
NBr
NI
4
[
15]
6
–
(
Scheme 2). Excellent conversion and selectivity was ob-
[
d]
Ͼ 99:1
Ͼ 99:1
Ͼ 99:1
Ͼ 99:1
Ͼ 99:1
Ͼ 99:1
86:14
Ͼ 99:1
–
5
served after 8 h, but reducing the pressure below 10 atmo-
spheres of carbon dioxide severely reduced the reactivity of
the catalyst.
[e]
[f]
16
50
15
60
30
51
40
0
1
2
3
4
5
6
7
Ͻ 5
Ͻ 5
86
72
59
0
–
60
60
30
90
77:23
90:10
58:42
96:4
Scheme 2. Darensbourg’s approach to TMC 1 and poly(TMC) 2.
18
NI
96
[
2
a] General conditions: Cu cathode, Mg anode, CO (1 atm,
balloon), supporting electrolyte (1.0 equiv.), MeCN, single com-
partment cell, 60 mA, 6 h. [b] Ratio calculated from the crude reac-
1
We have recently shown that electrosynthesis can be a tion H NMR spectrum by integration of cyclic carbonate vs. co-
powerful tool for a range of important reactions[ and can polymer signals. [c] Isolated yield of TMC 1 after chromatography.
16]
[
0
d] 0.25 equiv. Bu
4 4
NI employed. [e] 0.50 equiv. Bu NI employed. [f]
be employed in the catalyst-free synthesis of five-membered
ring cyclic carbonates under atmospheric pressure carbon
dioxide and mild temperatures.[ The importance of six-
membered ring cyclic carbonates and their inherent
thermodynamic instability prompted us to investigate this
important carbon dioxide insertion reaction. We believed
.75 equiv. Bu NI employed.
4
17]
We then turned our attention to the supporting electro-
that it should be possible to develop an electrochemical sys- lyte and a screen employing tetrabutylammonium chloride,
tem that is easy to set up, cheap, reliable, requires no ex- bromide, iodide and hexafluorophosphate identified the
pensive catalysts, runs under atmospheric CO2 pressures iodide as the most promising candidate, with 50% yield of
and at ambient temperatures. Importantly, employing an TMC 1 being formed at 25 °C with Ͼ 99:1 selectivity for
[
20]
electrosynthetic system is cost neutral in terms of energy the monomer (Table 1, Entry 2). Further studies showed
consumption if combined with a suitable renewable energy that 0.75 equiv. of the supporting electrolyte was required
source, for example, solar.
for good yield to be achieved (50%, Table 1, Entry 7) and
Eur. J. Org. Chem. 2015, 474–478
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
475

B. R. Buckley, A. P. Patel, K. G. U. Wijayantha
SHORT COMMUNICATION
an increase in yield to 60% could be achieved through a Table 2. A comparison of processes for 5,5-dimethyl-1,3-dioxan-2-
one 5 synthesis.[
a]
slight increase in the applied current (60 to 90 mA, Table 1,
Entry 9).
[
20]
A series of experiments to look at the effect of tempera-
ture on the reaction were also carried out and finally we
were able to obtain TMC 1 in 96% yield, although the reac-
tion was not quite 100% selective for the monomer (Table 1,
Entry 18).
Entry CO
2
Temp. [°C] Ratio
Yield 5 Ref.
Kleij and co-workers recently reported the synthesis of
five-membered cyclic carbonates in excellent yield with
either an iron- or aluminium-based catalyst at 10–2 atm
Pressure [atm] (time [h])
5:6
[%]
1[
a]
NR[f]
[21a]
10–2
10–2
35
35
1
85 (18 h)
70 (18 h)
NR
9
26
NR
NR
[b]
[21b]
2
54:46
[
21]
CO2.
They also reported high yields and selectivity of
[c]
[f]
[f]
[f]
[f]
[15]
[22]
3
4
NR
oxetane to TMC 1 with the same systems but observed that
addition of steric bulk to the oxetane substrate at the 3,3-
position (two methyl groups, 4) dramatically decreased the
[d]
110 (50 h) 88:12
50 (6 h)
[
e]
5
Ͼ 99:1 70
this work
[a] Conditions: [Fe(TPhOA)]
2
(0.5 mol-%), Bu
4
NI (5 mol-%),
yield and selectivity of the CO2 incorporation reaction MEK, CO (10–2 atm), 85 °C. [b] Conditions: Al triphenolate cata-
2
(
typically 9–28% yield, Table 2 Entries 1 and 2). Darens- lyst (0.5 mol-%), Bu
4
NI (2.5 mol-%), CO
2
(10–2 atm), 70 °C. [c]
(35 atm). [d]
(2 equiv.), CO (35 atm),
toluene, 110 °C. [e] Conditions: Cu cathode, Mg anode, CO
1 atm, balloon), Bu
VO(acac)
2
(5 mol-%), BuNBr (5 mol-%), 60 °C, CO
2
bourg has also reported that 3,3-substituted oxetanes are
3
+
(
salen)Cr chloride complex, Bu
4
NN
3
2
slow substrates for CO insertion at 35 atm but has not yet
2
2
disclosed the yields when employing his vanadium-cata-
(
4
NI (1.0 equiv.), MeCN, single compartment
[
15]
lysed conditions (Table 2, Entry 3).
When employing cell, 90 mA, 50 °C. [f] NR = not reported.
[
III]
(salen)Cr
chloride complexes, Darensbourg has reported
a product distribution of 88% in favour of copolymer 6,
when exploring the equilibrium distribution of a range of
[
22]
oxetanes.
A proposed mechanism is described in Scheme 3 in
Under our conditions the formation of 5,5-dimethyl-1,3- which magnesium iodide is prepared in situ, following the
dioxan-2-one 5 proceeded relatively smoothly with an un- reports of North and co-workers tributylamine is released
optimised 70% yield being obtained at 50 °C when em- under the reaction conditions[4g] and also activates CO2
ploying tetrabutylammonium iodide and 60 mA (Table 2, towards eventual incorporation to TMC, with magnesium
Entry 4).
iodide regeneration.
Scheme 3. Proposed mechanism for the formation of TMC 2.
476
www.eurjoc.org
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 474–478

Formation of Trimethylene Carbonate: Carbon Dioxide Utilization
[
4] a) M. North, B. Wang, C. Young, Energy Environ. Sci. 2011,
Conclusions
4
, 4163; b) M. North, C. Young, Catal. Sci. Technol. 2011, 1,
93; c) W. Clegg, R. W. Harrington, M. North, P. Villuendas, J.
We have developed, to the best of our knowledge, the
first selective procedure for the formation of the TMC
monomer 1 at atmospheric pressure carbon dioxide from
Org. Chem. 2010, 75, 6201; d) W. Clegg, R. W. Harrington, M.
North, R. Pasquale, Chem. Eur. J. 2010, 16, 6828; e) I. S. Met-
calfe, M. North, R. Pasquale, A. Thursfield, Energy Environ.
Sci. 2010, 3, 212; f) M. North, P. Villuendas, C. Young, Chem.
Eur. J. 2009, 15, 11454; g) M. North, R. Pasquale, Angew.
Chem. Int. Ed. 2009, 48, 2946; Angew. Chem. 2009, 121, 2990;
h) J. Meléndez, M. North, P. Villuendas, Chem. Commun. 2009,
[
23]
oxetane.
This process is one of only a handful of
approaches that allow the conversion of oxetane to the
cyclic carbonate rather than the thermodynamically more
stable polymer 2. The yields obtained are comparable or
better than those already reported in the area. The equip-
2577; i) J. Meléndez, M. North, R. Pasquale, Eur. J. Inorg.
Chem. 2007, 3323.
ment required to perform this CO incorporation reaction [5] D. J. Darensbourg, Inorg. Chem. 2010, 49, 10765.
2
is cheap and should be readily available in any undergradu- [6] J. Yoo, S. J. Na, H. C. Park, A. Cyriac, B. Y. Lee, Dalton Trans.
2
010, 39, 2622.
ate teaching facility, that is, copper wire, magnesium ribbon
and a power supply. The protocol described affords the
highest reported yield for the 3,3-dimethyl-substituted
[
7] D. R. Moore, M. Cheng, E. B. Lobkovsky, G. W. Coates, An-
gew. Chem. Int. Ed. 2002, 41, 2599; Angew. Chem. 2002, 114,
2711.
oxetane and we are currently exploring the CO insertion
2
[8] a) M. R. Kember, C. K. Williams, J. Am. Chem. Soc. 2012, 134,
15676; b) A. Buchard, F. Jutz, M. R. Kember, A. J. White, H. S.
Rzepa, C. K. Williams, Macromolecules 2012, 45, 6781; c)
M. R. Kember, F. Jutz, A. Buchard, A. J. P. White, C. K. Wil-
liams, Chem. Sci. 2012, 3, 1245; d) F. Jutz, A. Buchard, M. R.
Kember, S. B. Fredriksen, C. K. Williams, J. Am. Chem. Soc.
2011, 133, 17395; e) A. Buchard, M. R. Kember, K. G. Sande-
man, C. K. Williams, Chem. Commun. 2011, 47, 212; f) M. R.
Kember, A. Buchard, C. K. Williams, Chem. Commun. 2011,
47, 141; g) M. R. Kember, A. J. P. White, C. K. Williams, Inorg.
Chem. 2009, 48, 9535; h) M. R. Kember, P. D. Knight, P. T. R.
Reung, C. K. Williams, Angew. Chem. Int. Ed. 2009, 48, 931;
Angew. Chem. 2009, 121, 949.
into these challenging substituted oxetanes, for which there
are currently very few commercially available.
Experimental Section
Representative Procedure for the Formation of Cyclic Carbonates:
Trimethylcarbonate (TMC) (2):[
15,24]
Tetrabutylammonium iodide
(0.74 g, 2.0 mmol) was dissolved in acetonitrile (145 mL), the re-
2
sulting solution was flushed with CO for 1 h at room temperature
and trimethylene oxide (0.12 g, 2.0 mmol) added as a solution in
acetonitrile (5 mL). The reactor was heated to 75 °C and potential
was then applied to the system (constant current: 90 mA) for 6 h
in a single compartment cell [Mg anode and Copper(0) cathode].
On completion the reaction mixture was washed with aqueous HCl
[
[
9] A. Decortes, A. J. Kleij, ChemCatChem 2011, 3, 831.
10] a) J. H. Clements, Ind. Eng. Chem. Res. 2003, 42, 663; b) G.
Rokicki, Prog. Polym. Sci. 2000, 25, 259; c) D. J. Darensbourg,
W. Choi, P. Ganguly, C. P. Richers, Macromolecules 2006, 39,
4374; d) D. J. Darensbourg, W. Choi, C. P. Richers, Macromol-
(
0.1 m, 50 mL) followed by extraction with Et
combined organic extracts were then dried with MgSO
rated under reduced pressure to afford an amber oil, which was
suspended in EtOAc (100 mL). After 1 h the precipitated Bu NI
≈ 70%) was removed by filtration and the solvent evaporated un-
2
O (3ϫ 35 mL). The
ecules 2007, 40, 3521; e) D. J. Darensbourg, W. Choi, O. Kar-
roonnirun, N. Bhuvanesh, Macromolecules 2008, 41, 3493; f)
F. Nederberg, B. G. G. Lohmeijer, F. Leibfarth, R. C. Pratt, J.
Choi, A. P. Dove, R. M. Waymouth, J. L. Hedrick, Biomacrom-
olecules 2007, 8, 153; g) N. E. Kamber, W. Jeong, R. M. Waym-
outh, R. Pratt, B. G. G. Lohmeijer, J. L. Hedrick, Chem. Rev.
4
and evapo-
4
(
der reduced pressure to afford an amber oil. This crude material
was purified by column chromatography on silica gel eluting with
ethyl acetate/light petroleum to give a colourless solid (0.196 g,
2
007, 107, 5813; h) J. Mindemark, J. Hilborn, T. Bowden, Mac-
romolecules 2007, 40, 3515.
[
11] A. P. Pêgo, M. J. A. Van Luyn, L. A. Brouwer, P. B.
van Wachem, A. A. Poot, D. W. Grijpma, J. Feijen, J. Biomed.
Mater. Res. 2003, 67A, 1044 and references cited therein.
12] a) D. J. Darensbourg, A. I. Moncada, S. J. Wilson, in Green
Polymerization Methods (Eds.: R. T. Mathers, M. A. R. Meier),
Wiley-VCH, Weinheim, 2010; b) B. Hu, R. Zhuo, C. Fan, Po-
lym. Adv. Technol. 1998, 9, 145.
13] a) A. Baba, H. Meishou, H. Matsuda, Makromol. Chem. Rapid
Commun. 1984, 5, 665; b) A. Baba, H. Kashiwagi, H. Matsuda,
Tetrahedron Lett. 1985, 26, 1323.
6%). M.p. 45–47 °C (lit.[
CDCl , Me
C NMR (100 MHz, CDCl
IR (CH Cl ): ν˜ = 1252 (C–O), 1740 (C=O) cm .
21]
45–47 °C). H NMR (400 MHz,
Si): δ = 2.12–2.18 (m, 2 H), 4.45–4.48 (m, 4 H) ppm.
, Me Si): δ = 21.8, 68.0, 148.5 ppm.
1
9
3
4
13
3
4
[
–1
2
2
Acknowledgments
[
B.R. B. and K.G.U. W. would like to thank the Research Councils
UK for RCUK fellowships (EP/E50082X/1) and Loughborough
University for funding a PhD studentship to A.P. P.
[14] a) A. Baba, H. Kashiwagi, H. Matsuda, Organometallics 1987,
6, 137; b) M. Fujiwara, A. Baba, H. Matsuda, J. Heterocycl.
Chem. 1989, 26, 1659.
[
15] D. J. Darensbourg, A. Horn Jr, A. I. Moncada, Green Chem.
[
[
1] R. J. Pearson, M. D. Eisaman, J. W. G. Turner, P. P. Edwards,
Z. Jiang, V. L. Kuznetsov, K. A. Littau, L. di Marco, S. R. G.
Taylor, Proc. IEEE 2012, 100, 440.
2] Contribution of Working Group III to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change,
2010, 12, 1376.
[
16] a) B. R. Buckley, Y. Chan, N. Dreyfus, C. Elliott, F. Marken,
P. C. B. Page, Green Chem. 2012, 14, 2221; b) P. C. B. Page, F.
Marken, C. Williamson, Y. Chan, B. R. Buckley, D. Bethell,
Adv. Synth. Catal. 2008, 350, 1149.
2
007 (Eds.: B. Metz, O. R. Davidson, P. R. Bosch, R. Dave,
[17] B. R. Buckley, A. P. Patel, K. G. U. Wijayantha, Chem. Com-
L. A. Meyer), Cambridge University Press, United Kingdom
and New York, NY, USA.
mun. 2011, 47, 11888.
18] See ref.[ for optimized conditions.
17]
[
[
[
3] P. Styring, D. Jansen, H. de Coninck, K. Armstrong, Carbon
Capture and Utilisation in the green economy, Report No. 501,
July 2011, The Centre For Low Carbon Futures, ISBN 978–0–
19] See Table S1 in the Supporting Information for full details.
[20] V. Caló, A. Nacci, A. Monopoli, A. Fanizzi, Org. Lett. 2002,
4, 2561.
9572588–0–8.
Eur. J. Org. Chem. 2015, 474–478
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
477

B. R. Buckley, A. P. Patel, K. G. U. Wijayantha
[23] A low pressure CO route from 3-chloropropan-1-ol has been
reported: M. R. Reithofer, Y. N. Sum, Y. Zhang, Green Chem.
2013, 15, 2086.
[24] H. R. Kricheldorf, J. Jenssen, J. Macromol. Sci. Pure Appl.
Chem. 1989, 26, 631.
SHORT COMMUNICATION
[
21] a) C. J. Whiteoak, E. Martin, M. M. Belmonte, J. Benet-Buch-
holz, A. W. Kleij, Adv. Synth. Catal. 2012, 354, 469; b) C. J.
Whiteoak, N. Kielland, V. Laserna, E. C. Escudero-Adán, E.
Martin, A. W. Kleij, J. Am. Chem. Soc. 2013, 135, 1228.
2
[22] D. J. Darensbourg, A. I. Moncada, S.-H. Wei, Macromolecules
2011, 44, 2568.
Received: October 22, 2014
Published Online: December 10, 2015
478
www.eurjoc.org
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2015, 474–478