ChemComm
Communication
a
Table 1 Hydrogenation of alkenes catalyzed by Fe
3
O
4
@GO-2
metal leaching). The catalyst can be efficiently recycled and
reused for ten successive catalytic cycles for hydrogenation of
b
2
À1
Entry Alkene
Time (h) Conversion (%) TOF Â 10 (h
)
4-methylstyrene under optimized conditions (Fig. S12, ESI†). No
leaching of Fe from Fe O @GO-2 catalyst is observed (AAS
3
4
1
20
80
54.1
analysis, Section S15, ESI†), suggesting that GO is an excellent
1
6
support for the liquid phase catalytic reactions.
In summary, Fe nanoparticles embedded in GO behave
3 4
O
2
3
4
5
6
7
8
20
4
94
99
85
99
86
98
55
63.5
334.8
95.8
as magnetically recoverable heterogeneous nanocatalysts for
alkene hydrogenation with low catalyst loading using hydrazine
hydrate as the hydrogen source in EtOH at 80 1C together with a
À1
high TOF of 44500 h . This newly developed protocol avoids
12
18
10
6
use of the highly flammable H2 gas at high pressure and
temperature.
74.4
This work was financially supported by the Singapore National
Research Foundation Fellowship (NRF2009NRF-RF001-015), the
Singapore National Research Foundation CREATE program – the
Singapore Peking University Research Centre for a Sustainable Low-
Carbon Future, and the NTU-A*Star Centre of Excellence for Silicon
Technologies (A*Star SERC No.: 112 351 0003). AB thanks DST, New
Delhi for financial support.
116.3
221
16
46.5
Notes and references
9
12
20
90
70
102
1
2
3
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1
0
47.3
c
4 D. Gartner, A. Welther, B. R. Rad, R. Wolf and A. Jacobi von
1
1
1
12
18
87
99
98.0
74.4
Wangelin, Angew. Chem., Int. Ed., 2014, 53, 3722–3726.
5
6
M. Stein, J. Wieland, P. Steurer, F. Tçlle, R. Mulhaupt and B. Breit,
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2
Q. M. Kainz, R. Linhardt, R. N. Grass, G. Vil ´e , J. P ´e rez-Ram ´ı rez,
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7 (a) E. W. Schmidt, Hydrazine and Its Derivatives: Preparation, Proper-
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Reaction conditions: alkene (0.25 mmol), Fe
3
O
4
@GO-2 (15 mg), N
2
H
4
Á
b
H
2
O (10 equivalent, 2.5 mmol, 125 mg), EtOH (3 mL), 80 1C. Deter-
mined by GC analysis. TOF = Turn over frequency (moles of substrate
converted per mole of active sites per hour). All the products were
confirmed by GC-MS analysis. Reaction was conducted with 10 mmol
c
of 4-methylstyrene.
8
M. Lamani, R. Siddappa, S. Guralamata and K. R. Prabhu, Chem.
Commun., 2012, 48, 6583–6585.
9
A. Dhakshinamoorthy, M. Alvaro and H. Garcia, Adv. Synth. Catal.,
consistent conversion (Table 1, entry 11). The TOF values range
from 4650–33 482 h and these are impressively high, suggesting
the huge future potential of the Fe O @GO nanocatalyst.
3 4
To confirm that the alkene hydrogenation catalytic reaction
is indeed heterogeneous in nature, we performed the hot
filtration test and the leaching test by considering 4-methyl-
styrene as the model substrate (see ESI,† Section S15). In order
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À1
1
1
1
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1
to check the mechanical stability of the Fe O @GO-2 catalyst
3
4
we carried out TEM (Fig. S13, ESI†) and XPS (Fig. S14A, ESI†) 14 Z.-S. Wu, S. Yang, Y. Sun, K. Parvez, X. Feng and K. Mullen, J. Am.
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analyses, which suggest that our catalyst is stable under the
reaction conditions. The efficacy of a Fe O @GO-2 nanocatalyst
3 4
is also evident from its recyclability and stability (for example, no
1
1
5 A. C. Ferrari and D. M. Basko, Nat. Nanotechnol., 2013, 8, 235–246.
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Chem. Commun., 2014, 50, 12095--12097 | 12097