Carboxylic Group Embedded Carbon Balls as a New Supported Catalyst for Hydrogen Economic Reactions
Bordoloi
Table V. Evaluation of leaching and recyclability of Ru/carbon catalyst
reduction of ketones and aldehydes. The reactivity study
of ketones, aldehydes and alcohols with different molec-
ular structure showed that the approach can be applicable
for wide verity of substrates. The high catalytic activity of
Ru/Carbon for the MPV reaction can be attributed to the
higher dispersibility of ruthenium complex in the support.
The catalyst was reused for four recycles, with same activ-
ity and selectivity. Thus, we consider this protocol to be a
readily accessible pathway to highly immobilized transfer
hydrogenation catalyst.
for MPV reductiona.
Ru content
TONb
Selectivity (%)
Fresh
0.05 mmol/g
1260
1240
1240
1200
1200
99
99
99
99
99
1st cycle
2nd cycle
3rd cycle
4th cycle
nd
nd
nd
nd
Notes: aReaction conditions: 10 mmol of the substrate, 2-propanol 100 mmol, tem-
b
perature 85 ꢀC, time 12 h, substrate to catalyst molar ratio = 2000:1; TON (turn
over number) mole substrate converted per mole of Ru.
Acknowledgments: Author gratefully acknowledges
Ruhr University, Bochum, Germany for instrumental
support.
carbon–carbon double bonds which reinforces selectivity
of the current methodology.
3.1. Catalyst Stability
References and Notes
To investigate whether any active species of the catalyst
were leaching into the reaction medium, we carried out
MPV reduction of cyclohexanone under selected condi-
tions with Ru/Carbon catalyst. The reaction was stopped
after 3 h, after which the reaction was cooled to room tem-
perature and conversion of cyclohexanone was estimated.
Then the catalyst was separated by hot filtration, the fil-
trate was added to the vessel, and the reaction was contin-
ued for another 10 h. No increase in substrate conversion
was observed; it remained the active species of the catalyst
into the reaction mixture; the catalyst truly acted as if it
1. P. T. Anastas and J. C. Warner, Green Chemistry: Theory and
Practice, Oxford University Press, New York (1998).
2. J. A. Gladysz, Chem. Rev. 102, 3215 (2002).
3. C. E. Song, D. H. Kim, and D. S. Choi, Eur. J. Inorg. Chem.
2006, 2927 (2006).
4. M. D. Jones, R. Raja, J. M. Thomas, B. F. G. Johnson, D. W. Lewis,
J. Rouzard, and K. D. M. Harris, Angew. Chem. Int. Ed. 42, 4326
(2003).
5. F. R. Reinoso, Carbon 36, 159 (1998).
6. G. J. Kim and J. H. Shin, Catal. Lett. 63, 205 (1999).
7. D. Chatterjee and A. Mitra, J. Mol. Catal. A: Chem. 144, 363 (1999).
8. P. Piaggio, C. Langham, P. McMorn, D. Betchell, P. C. Bulman-
Delivered by Publishing Technology to: McMaster University
Page, F. E. Hancock, C. Sly, and G. J. Hutchings, J. Chem. Soc.
were heterogeneous. This observation confirms the com-
IP: 94.139.167.155 On: Wed, 02 Mar 2016 10:07:40
Perkin Trans. 2, 143 (2000).
plete absence of leaching of any active species in reaction
Copyright: American Sc9ie. nDti.fiAc. PAunbnilsisahnedrEs. N. Jacobsen, J. Am. Chem. Soc. 121, 4147
(1999).
medium.
10. A. Behr, Angew. Chem. Int. Ed. Engl. 27, 661 (1988).
11. P. Haynes, L. H. Slaugh, and J. F. Kohnle, Tetrahedron Lett. 5, 365
(1970).
12. R. A. Sheldon, Pure Appl. Chem. 72, 1233 (2000).
13. S. Gladiali and E. Alberico, Chem. Soc. Rev. 35, 226 (2006).
14. S. Gladiali and G. Mestroni, Transition Metals for Organic Synthesis,
edited by M. Beller and C. Bolm, Wiley-VCH, Weinheim (2004),
Vol. 145.
15. H. U. Blaser, C. Malan, B. Pugin, F. Spindler, and M. Studer, Adv.
Synth. Catal. 345, 103 (2003).
16. R. Noyori and S. Hashiguchi, Acc. Chem. Res. 30, 97 (1997).
17. G. Zassinovich, G. Mestroni, and S. Gladiali, Chem. Rev. 51, 1051
(1992).
We evaluated the recyclability of the Ru/Carbon catalyst
in the MPV reduction of cyclohexanone in four runs; the
results are presented in Table V. After each run, the cat-
alyst was washed repeatedly with dichloromethane, dried
under vacuum at 40 ꢀC for 6 h, and then used in the
MPV reduction with a fresh reaction mixture. Cyclohex-
anone conversion was practically almost same (63%) in
all four recycles, with a marginal decrease at the third and
fourth cycles. This could be due to mechanical loss of cat-
alyst during regeneration. This finding demonstrates the
successful immobilization of the Ruthenium complex onto
the novel carbon support.
18. R. Demir-Cakan, N. Baccile, M. Antonietti, and M. Titirici, Chem.
Mater. 21, 484 (2009).
19. R. M. Silverstein and F. X. Webster, Spectroscopic Identification of
Organic Compounds, Inc., 6th edn., John Wiley and Sons (ASIA)pte
Ltd., 2 Clementi Loop#02-01, Singapore (1996).
20. W. Geng, T. Nakajima, H. Takanashi, and A. Ohki, Fuel 88, 139
(2009).
21. M. Rohr, M. Gunther, F. Jutz, J. D. Grunwaldt, H. Emerich, W. Beek,
and A. Baiker, App. Catal. A 296, 238 (2005).
22. A. Corma, M. E. Domine, and S. Valencia, J. Catal. 215, 294 (2003).
23. P. P. Samuel, S. Shylesh, and A. P. Singh, J. Mol. Catal. A chem.
266, 11 (2007).
4. CONCLUSIONS
The report demonstrated a new, effective class of hetero-
geneous catalyst through synthesis of ruthenium complex
covalently anchored carboxylic functionalized carbon in
least steps. Catalyst diagnosis demonstrated the success-
ful incorporation of carboxylic groups and metal complex
onto the carbon material. The catalyst system was found
to be the ideal heterogeneous catalyst system for the MPV
24. Y. Zhu, G. Chuah, and S. Jaenicke J. Catal. 227, 1 (2004).
Received: 24 April 2014. Accepted: 18 May 2014.
3076
J. Nanosci. Nanotechnol. 16, 3071–3076, 2016