Communication
ChemComm
A reusability test of the catalyst (Table S1, ESI†) was conducted. Notes and references
ICP-AES was performed after each run to detect Cu leaching and
1 A. C. Catino and E. Farris, Concise Encyclopedia of Chemical Technology,
Wiley, New York, 1985, ch. VII.
2 B. R. Thomas and T. William, Science, 1999, 284, 1477.
the results are listed in Table S1, in the ESI.† The test showed that
the catalyst retained most of its activity upon recycling after 5
consecutive catalytic runs and hardly any leaching of metals was
observed. Furthermore, the used catalyst was characterized by
XRD (Fig. 1c) and TEM (Fig. S4b, ESI†). The XRD patterns and the
morphology for the used catalyst were not changed, which showed
that the catalyst remained unchanged even after 5 cycles. Thus the
catalyst demonstrated good reusability and was therefore truly
heterogeneous in nature.
To conclude, we report a facile route for the synthesis of Cu(II)
nanoclusters supported on CuCr2O4 nanoparticles. The material
displayed excellent catalytic performance in the sustainable oxya-
mination reaction of benzene to aniline in a direct process using
NH3 and H2O2, achieving high efficiency in terms of activity,
selectivity, mild conditions and catalyst recyclability. The compo-
nent, Cu(II), is found to exert high influence on both the conversion
rate and product selectivity. Furthermore, the catalyst can be reused
several times without any significant activity loss. These effects
probably stem directly from the synergy between the Cu(II)
and CuCr2O4 spinel nanoparticles. The process may serve as a
promising replacement of traditional aniline production.
¨
3 N. Hoffmann, E. Loffler, N. A. Breuer and M. Muhler, ChemSusChem,
2008, 1, 393.
4 N. Hoffmann and M. Muhler, Catal. Lett., 2005, 103, 155.
5 J. T. Anders, US Pat., 2009/0292144, 2009.
¨
6 J. Becker and W. F. Holderich, Catal. Lett., 1998, 54, 125.
7 H. Yuzawa and H. Yoshida, Chem. Commun., 2010, 46, 8854.
8 M. Romero, Y. Harrak, J. Basset, J. A. Oru´e and M. D. Pujol, Tetra-
hedron, 2009, 65, 1951.
9 (a) N. I. Kuznetsova, L. G. Detusheva, V. A. Likholobov, G. P. Pez and
H. Cheng, J. Mol. Catal. A: Chem., 2000, 161, 1; (b) S. Singha and
K. Parida, Catal. Sci. Technol., 2011, 1, 1496.
10 J. L. Klinkenberg and J. F. Hartwig, Angew. Chem., 2011, 50, 86.
11 B. Guo, Q. Zhang, G. Li, J. Yao and C. Hu, Green Chem., 2012, 14, 1880.
12 (a) R. Prasad and P. Singh, Catal. Rev. Sci. Eng., 2012, 54, 224;
(b) Z. Xiao, S. Jin, M. Pang and C. Liang, Green Chem., 2013, 15, 891.
13 A. M. Kawamoto, L. C. Pardini and L. C. Rezende, Aerosp. Sci.
Technol., 2004, 8, 591.
14 (a) V. Z. Fridman and A. A. Davydov, J. Catal., 2000, 195, 20; (b) B. Sarkar,
P. Prajapati, R. Tiwari, R. Tiwari, S. Ghosh, S. S. Acharyya, C. Pendem,
R. K. Singha, L. N. S. Konathala, J. Kumar, T. Sasaki and R. Bal, Green
Chem., 2012, 14, 2600; (c) T. W. Kim, M. W. Song, H. L. Koh and
K. L. Kim, Appl. Catal., A, 2002, 210, 35.
15 A. Dandeker and M. A. Vannice, J. Catal., 1998, 178, 621.
16 S. S. Acharyya, S. Ghosh, R. Tiwari, B. Sarkar, R. K. Singha,
C. Pendem, T. Sasaki and R. Bal, Green Chem., 2014, 16, 2500.
17 M. A. Mantegazza, G. Leofanti, G. Petrini, M. Padovan, A. Zeccina
and S. Bordiga, in New Developments in Selective Oxidation, ed.
V. C. Corberan and S. V. Bellon, Elsevier, New York, 1994, p. 51.
S.S.A. thanks CSIR and S.G. thanks UGC, New Delhi, India,
for their respective fellowships. R.B. thanks CSIR, New Delhi, for
financial support in the form of the 12 FYP Project (CSC-0125,
CSC-0117). The Director of CSIR-IIP is acknowledged for his help
and encouragement. The authors thank the Analytical Section
Division, IIP, for the analytical services.
¨
18 E. Roduner, W. Kaim, B. Sarkar, V. B. Urlacher, J. Pleiss, R. Glaser, W. D.
Einicke, G. A. Sprenger, U. Beifuß, E. Klemm, C. Liebner, H. Hieronymus,
S. F. Hsu, B. Plietker and S. Laschat, ChemCatChem, 2013, 5, 82.
19 A. Hausser, M. Trautmann and E. Roduner, Chem. Commun., 2011,
47, 6954.
Chem. Commun.
This journal is ©The Royal Society of Chemistry 2014