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3
Dead volume determination of a packed CatCart cartridge
(dt, J=9.6, 7.0 Hz, 6H); C NMR (75 MHz, DMSO): d=153.9, 140.0,
39.3, 113.6, 101.5, 101.2, 64.6, 63.3, 15.4, 15.3 ppm.
1
The sealing and filter unit of a representative cartridge was careful-
ly removed at one end. Afterwards, the nano-Fe O @Al O material
Methyl 3-aminobenzoate (Table 3, entry 7): From a solution of
0.1m methyl 3-nitrobenzoate in MeOH at flow rate of
3
4
2
3
from the cartridge was filled in a preweighed volumetric flask
2 mL). After weighing, MeOH was added to result in an overall
a
À1
1
(
0.5 mLmin . Yield: 44.5 mg (98%); H NMR (300 MHz, DMSO): d=
7.22–7.04 (m, J=13.1, 7.6, 1.6 Hz, 3H), 6.93–6.39 (m, 1H), 5.37 (s,
volume of 2 mL. The mass of the added solvent was determined to
13
calculate the volume of nano-Fe O @Al O (ꢀ270 mL). This resulted
2H), 3.80 ppm (s, 3H); C NMR (75 MHz, DMSO): d=167.2, 149.4,
3
4
2
3
in a dead volume of about 600 mL because the total volume of
a CatCart cartridge was 880 mL.
130.8, 129.3, 118.8, 116.6, 114.3, 52.2 ppm.
3
-Aminobenzonitrile (Table 3, entry 8): From a solution of 0.1m 3-
nitrobenzonitrile in MeOH at a flow rate of 1 mLmin . Yield:
4.5 mg (97%); H NMR (300 MHz, CDCl ): d=7.36–7.15 (m, 1H),
3
.09–6.98 (m, 1H), 6.94–6.81 (m, 2H), 3.81 ppm (s, 2H); C NMR
): d=146.7, 130.1, 121.9, 119.3, 119.2, 117.3,
À1
1
3
1
3
7
Representative procedure for the reduction of nitroarenes
under continuous-flow conditions (Table 3)
(75 MHz, CDCl
3
112.6 ppm.
1
,4-Diaminobenzene (Table 3, entry 9): From a solution of 0.1m
For a typical experiment, a 0.1m solution (3 mL) of the respective
nitroarene in methanol containing N H ·H O (1.8 equiv) was
pumped through a fresh catalyst cartridge (CatCart, filled with
À1
4
-nitroaniline in MeOH at a flow rate of 1 mLmin . Yield: 32 mg
2
4
2
1
(98%); H NMR (300 MHz, DMSO): d=6.35 (s, 4H), 4.18 ppm (s,
13
4
H); C NMR (75 MHz, DMSO): d=139.4, 115.7 ppm.
ꢀ
920 mg of nano-Fe O @Al O ) at 1508C at a flow rate of 0.5–
mLmin . After passing a back-pressure regulator (30 bar), the re-
3 4 2 3
À1
1
4
-Fluoroaniline (Table 3, entry 10): From a solution of 0.1m 4-
action mixture was collected and the solvent was removed careful-
ly under reduced pressure. The crude mixture was dissolved in
ethyl acetate and filtered through a plug of silica gel (10 g). Unless
otherwise noted, the pure amine was isolated after careful evapo-
ration of the solvent.
À1
fluoro-4-nitrobenzene in MeOH at a flow rate of 1 mLmin . Yield:
1
3
0 mg (90%) after column chromatography; H NMR (300 MHz,
DMSO): d=6.89–6.76 (m, 1H), 6.59–6.49 (m, 1H), 4.93 ppm (s, 1H);
13
C NMR (75 MHz, DMSO): d=156.3, 153.0, 145.61,145.63, 115.7,
115.4, 115.1, 115.0 ppm.
Aniline (Table 3, entry 1): From a solution of 1m nitrobenzene in
À1
1
MeOH with a flow rate of 1 mLmin . Yield: 277 mg (99%); H NMR
Long-term stability and leaching study in continuous flow
(Figure 6)
(
(
300 MHz, CDCl ): d=7.24–7.12 (m, 2H), 6.83–6.75 (m, 1H), 6.71
3
ddd, J=4.3, 3.2, 1.7 Hz, 2H), 3.66 ppm (s, 2H); C NMR (75 MHz,
13
CDCl ): d=146.3, 129.1, 118.4, 114.8 ppm.
3
Solutions of nitrobenzene in MeOH or MeCN (0.5–1m) containing
N H ·H O (1.8 equiv) were passed through the continuous reactor
equipped with a fresh catalyst cartridge (CatCart, filled with
2
-Chloroaniline (Table 3, entry 2): From a solution of 1m 1-chloro-
2
4
2
À1
2
3
1
1
-nitrobenzene in MeOH at a flow rate of 1 mLmin . Yield:
79 mg (99%); H NMR (300 MHz, CDCl ): d=7.27 (dd, J=7.8,
.2 Hz, 1H), 7.09 (td, J=8.0, 1.4 Hz, 1H), 6.78 (dd, J=8.0, 1.5 Hz,
H), 6.71 (ddd, J=7.9, 7.4, 1.5 Hz, 1H), 4.06 ppm (s, 2H); C NMR
À1
1
ꢀ920 mg of nano-Fe O @Al O ) for 1–10 h with a 1–3 mLmin
3
4
2
3
3
flow rate at 1508C and 30 bar back pressure. Every 60 min, the
conversion was determined by GC-FID. For ICPMS determination of
iron leaching, an aliquot (50 mL) of the collected solution was
evaporated carefully and analyzed after dissolving the solid residue
1
3
(
75 MHz, CDCl ): d=142.9, 129.4, 127.6, 119.3, 119.0, 115.9 ppm.
3
3
,4-Dichloroaniline (Table 3, entry 3): From a solution of 0.1m 1,2-
in HNO (1 mL).
3
À1
dichloro-4-nitrobenzene in MeOH at a flow rate of 1 mLmin
.
1
Yield: 47 mg (97%); H NMR (300 MHz, DMSO): d=7.18 (d, J=
8
5
.7 Hz, 1H), 6.74 (d, J=2.3 Hz, 1H), 6.52 (dd, J=8.7, 2.4 Hz, 1H), Acknowledgements
13
.54 ppm (s, 2H); C NMR (75 MHz, DMSO): d=149.6, 131.3, 130.9,
1
16.4, 114.9, 114.5 ppm.
This work was supported by a grant from the Christian Doppler
Research Society (CDG). We also gratefully acknowledge support
from NAWI Graz. We thank Prof. W. Gçssler for performing ICPMS
analysis and Prof. R. Luque for providing samples of SBA15 and
Al-SBA15. We are particularly grateful to the Facility of Analysis
and Characterization of Solids and Surfaces of SAIUE, Spain (fi-
nanced by UEX, Junta de Extremadura, MICINN, FEDER and FSE).
Technical help with the filling of the CatCarts by ThalesNano is
also acknowledged.
4
0
1
-(Pyridin-4-ylmethyl)aniline (Table 3, entry 4): From a solution of
.1m 4-(4-nitrobenzyl) pyridine in MeOH at a flow rate of
À1
1
mLmin . Yield: 54 mg (98%); H NMR (300 MHz, DMSO): d=8.42
(
dd, J=4.5, 1.5 Hz, 1H), 7.18 (d, J=5.8 Hz, 1H), 6.88 (d, J=8.3 Hz,
1
3
1
H), 6.50 (d, J=8.3 Hz, 1H), 4.94 (s, 1H), 3.75 ppm (s, 1H); C NMR
(
75 MHz, CDCl ): d=151.1, 149.8, 144.9, 130.0, 128.4, 124.0, 115.2,
3
4
0.6 ppm.
4
-Methoxyaniline (Table 3, entry 5): From a solution of 0.1m 1-
À1
methoxy-4-nitrobenzene in MeOH at a flow rate of 0.5 mLmin .
Yield: 35 mg (92%) after column chromatography; H NMR
1
(
3
300 MHz, CDCl ): d=6.86–6.73 (m, 2H), 6.71–6.62 (m, 2H), 3.77 (s,
H), 3.42 ppm (s, 2H); C NMR (75 MHz, CDCl ): d=152.5, 139.8,
3
Keywords: anilines
microreactors · nanoparticles
·
heterogeneous catalysis
·
iron
·
3
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116.5, 114.8, 55.5 ppm.
[
1] a) Microreactors (Eds.: W. Ehrfeld, V. Hessel, H. Lçwe), Wiley-VCH, Wein-
heim, 2000; b) Chemical Micro Process Engineering (Eds.: V. Hessel, S.
Hardt, H. Lçwe), Wiley-VCH, Weinheim, Germany, 2004; c) Micro Process
Engineering (Eds.: V: Hessel, A. Renken, J. C. Shouten, J.-i. Yoshida),
Wiley-Blackwell, Oxford, 2009; d) Microreactors in Organic Synthesis and
Catalysis (Ed.: T. Wirth), Wiley-VCH, Weinheim, 2013; e) Microreactors in
2
,5-Diethoxyaniline (Table 3, entry 6): From a solution of 0.1m
1
0
6
2
,3-diethoxy-5-nitrobenzene in MeOH at flow rate of
a
À1
1
.5 mLmin . Yield: 52 mg (95%); H NMR (300 MHz, DMSO): d=
.62 (t, J=13.4 Hz, 1H), 6.26 (t, J=11.7 Hz, 1H), 6.02 (dd, J=8.6,
.7 Hz, 1H), 4.69 (s, 2H), 3.87 (dq, J=13.8, 6.9 Hz, 4H), 1.28 ppm
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2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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