Paper
NJC
Recycling of the ionic liquid/catalyst systems in the reactions
preformed in microreactors
project OPUS (No. UMO-2012/05/B/ST5/00375). Moreover,
Rafal Kukawka is a scholarship holder of the Adam Mickiewicz
University Foundation for the academic year 2017/2018.
The reuse of ionic liquid in subsequent cycles in a microreactor
system was examined. For this purpose a mixture of substrates
(a mixture of 1,1,1,3,5,5,5-heptamethyltrisiloxane and 1-octene
in an equimolar ratio of 1 : 1) was dosed from one syringe pump
with a flow rate of 0.6 ml minÀ1, and mixtures of ionic liquid
with catalyst (catalyst added to match the concentration
equal to 1 Â 10À4 mol per mole of HMTS) with a flow rate of
0.3 ml minÀ1 was dosed from the second syringe pump. Both
streams were pumped to the mixer (capacity 0.2 ml), and then
to the microreactors (1.2 ml + 1.6 ml) and to a Teflon tubular
reactor (6 ml) to achieve 10 minutes of residence time of
Notes and references
´
1 B. Marciniec, H. Maciejewski, C. Pietraszuk and P. Pawluc,
Hydrosilylation. A Comprehensive Review on Recent Advances,
ed. B. Marciniec, Springer, 2009.
´
2 H. Maciejewski, A. Wawrzynczak, M. Dutkiewicz and R. Fiedorow,
J. Mol. Catal. A: Chem., 2006, 257, 141; H. Maciejewski, K. Szubert,
B. Marciniec and J. Pernak, Green Chem., 2009, 11, 1045;
H. Maciejewski, I. Dabek, R. Fiedorow and K. Szubert,
Curr. Trends Polym. Sci., 2011, 15, 45.
substrates in the reactor at a total flow rate of 0.9 ml minÀ1
.
The mixer and microreactors were heated in an oil bath to
110 1C. After the substrates and IL passed through the reactor,
the biphasic mixture was collected, cooled down to 0 1C to
avoid further reaction and then separated. The lower phase
(ionic liquid with catalyst) was separated, weighed and reused
in the next reaction cycle in the microreactor system using the
same reaction protocol as described above. This reaction was
repeated four times in order to determine how many times the
IL with catalyst can be reused.
3 P. D. Fletcher, S. J. Haswell, E. Pombo-Villar, B. H. Warrington,
P. Watts, S. Y. F. Wong and X. Zhang, Tetrahedron, 2002,
58, 4735.
4 M. Miyazaki, M. P. Briones-Nagata, T. Honda and
H. Yamaguchi, Microreactors in Organic Chemistry and Catalysis,
Wiley-VCH, 2nd edn, 2013, p. 289; K. Basavaraju, S. Sharma,
R. Maurya and D. Kim, Angew. Chem., 2013, 125, 6867;
R. Munirathinam, J. Huskens and W. Verboom, Adv. Synth.
Catal., 2012, 2, 1243; E. Gross, X. Shu, S. Alayoglu, H. A.
Bechtel, M. C. Martin, F. Dean Toste and G. A. Somorjai,
J. Am. Chem. Soc., 2014, 136, 3624; R. Greco, L. Caciolli,
A. Zaghi, O. Pandoli, O. Bortolini, A. Cavazzini, C. De Risi
and A. Massi, React. Chem. Eng., 2016, 1, 183.
5 P. Watts and C. Wiles, J. Chem. Res., 2012, 36, 181.
6 E. S. Borovinskaya, V. M. Uvarov, F. Schael, D. A. Vekki and
W. Reschetilowski, React. Kinet., Mech. Catal., 2011, 104, 345;
R. Bandari and R. Buchmeiser, Catal. Sci. Technol., 2012, 2, 220.
7 R. Kukawka, A. Pawlowska-Zygarowicz, M. Dutkiewicz,
H. Maciejewski and M. Smiglak, RSC Adv., 2016, 6, 61860.
8 A. Odedra, K. Geyer, T. Gustafsson, R. Gilmour and P. Seeberger,
Chem. Commun., 2008, 3025.
9 N. Hofmann, A. Bauer, T. Frey, M. Auer, V. Stanjek, P. S.
Schulz, N. Taccardi and P. Wasserscheid, Adv. Synth. Catal.,
2008, 350, 2599.
10 W. Zielinski, R. Kukawka, H. Maciejewski and M. Smiglak,
Molecules, 2016, 21, 1110; H. Maciejewski, K. Szubert and
B. Marciniec, Catal. Commun., 2012, 24, 1; H. Maciejewski,
A. Wawrzynczak, M. Dutkiewicz and R. Fiedorow, J. Mol.
Catal. A: Chem., 2006, 257, 141.
Thermogravimetric analysis (TGA)
Thermogravimetric analysis was performed using a TGA Q50
Texas Instrument. Samples of 8–15 mg were heated from 25 1C
to 80 1C at a heating rate of 10 1C minÀ1 with a 10 min isotherm
at 80 1C under a nitrogen atmosphere. This isotherm step was
intended to help in removing any remaining water and possible
volatile impurities present in the samples. Then the samples
were heated to 110 1C at a heating rate of 10 1C minÀ1 and the
samples were held at this temperature for 10 hours. As a result,
we have observed loss of weight at the level of maximum 0.4%,
which proves stability of ionic liquid at reaction conditions for
extended period of time (Table S1, ESI†).
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
This work was supported by the National Science Centre 11 B. Marciniec and P. Krzyzanowski, J. Organomet. Chem.,
(Poland), project OPUS (No. UMO-2014/15/B/ST5/04257) and 1995, 493, 261–266.
New J. Chem.
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