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a magnetic stirrer, a Teflon® inset and a pressure controller.
Reactions under continuous flow were carried out using an
inert reactor system constructed at ICCOM.18 The catalyst was
packed into a commercial Omnifit Glass Column (3.0 i.d. × 25
length mm).
2 (a) I. T. Horváth, H. Mehdi, V. Fabos, L. Boda and
L. T. Mika, Green Chem., 2008, 10, 238; (b) J. Q. Bond,
D. M. Alonso, D. Wang, R. M. West and J. A. Dumesic,
Science, 2010, 327, 1110; (c) D. Martin Alonso,
S. G. Wettstein and J. A. Dumesic, Green Chem., 2013, 15,
584.
Synthesis of the catalyst
3 For recent reviews, see: (a) Catalysis for Renewables, ed.
G. Centi and R. A. van Santen, Wiley-VCH, Weinheim,
2007; (b) J. A. Melero, J. Iglesias and A. Garcia, Energy
Environ. Sci., 2012, 5, 7393; (c) J. C. Serrano-Ruiz, A. Pineda,
A. M. Balu, R. Luque, J. M. Campelo, A. A. Romero and
J. M. Ramos-Fernández, Catal. Today, 2012, 195, 162.
4 For recent examples of homogeneous catalysts, see:
(a) F. M. A. Geilen, B. Engendahl, A. Harwardt,
W. Marquardt, J. Klankermayer and W. Leitner, Angew.
Chem., Int. Ed., 2010, 49, 5510; (b) M. Chalid,
A. A. Broekhius and H. J. Heeres, J. Mol. Catal. A: Chem.,
2011, 341, 14; (c) W. Li, J. H. Xie, H. Lin and Q. L. Zhou,
Green Chem., 2012, 14, 2388; (d) J. Deng, Y. Wang, T. Pan,
Q. Xu, Q. X. Guo and Y. Fu, ChemSusChem, 2013, 6, 1163.
5 For a recent review on heterogeneous catalysts, see:
W. R. H. Wright and R. Palkovits, ChemSusChem, 2012, 5,
1657.
6 For recent examples of heterogeneous catalysts, see:
(a) M. G. Al-Shaal, W. R. H. Wright and R. Palkovits, Green
Chem., 2012, 14, 1260; (b) A. M. Raspolli Galletti,
C. Antonetti, E. Ribechini, M. P. Colombini, N. Nassi o Di
Nasso and E. Bonari, Appl. Energy, 2013, 102, 157;
(c) C. Delhomme, L. A. Schaper, M. Zhang-Preße,
G. Raudaschl-Sieber, D. Weuster-Botz and F. E. Kühn,
J. Organomet. Chem., 2013, 724, 297; (d) K. Yan, T. Lafleur,
G. Wu, J. Liao, C. Ceng and X. Xie, Appl. Catal., A, 2013,
468, 52.
In a typical procedure, 0.600 g of dry DOWEX 50WX2 cation-
exchange resin (H+ form, gel-type, 4.8 meq g−1 exchange
capacity) were added to RuCl3 (18.1 mg, 0.087 mmol) in water
(34 mL) The mixture was stirred at room temperature for 4
days. The resin was washed with deionized water and treated
with an aqueous solution of NaBH4 (98.6 mg, 2.62 mmol) at
0 °C. The suspension was then stirred at room temperature
for 1 h. The resulting black resin was washed with deionized
water (5 × 50 mL), methanol (3 × 50 mL) and diethyl ether
(3 × 50 mL), and was dried in a stream of N2 overnight.
Catalytic conversion of LA to GVL under batch conditions
In a typical experiment, a degassed solution of LA in water
(2.15 mmol, 5 mL) was transferred under nitrogen in an auto-
clave containing the supported catalyst (60 mg, 0.005 mmol
Ru). N2 was then replaced with H2 and the autoclave was
charged with the desired pressure of H2, stirred at 150 rpm
and heated to the selected temperature. After the desired time,
the reactor was cooled down and depressurized. The solution
was removed and analysed by GC, HPLC, GC-MS, NMR and
ICP-OES. The reaction products were unequivocally identified
by GC, GC-MS and NMR spectra of authentic specimens.
Catalytic conversion of LA to GVL under continuous flow
conditions
In a typical experiment, a degassed solution of LA in water was
flowed through the dry packed catalyst (40 mg) at a constant
rate of 0.15 mL min−1 until the catalyst was completely wet. H2
was then simultaneously flowed at a constant rate of 1 mL
min−1 and room temperature. The column was heated at
70 °C, and attainment of steady state conditions, ca. 1 h, was
then taken as the reaction start time. The product solution was
periodically analysed by GC, HPLC and ICP-OES.
7 (a) Catalyst Separation, Recovery and Recycling; Chemistry
and Process Design, ed. D. J. Cole-Hamilton and R. P. Tooze,
Springer, Dordrecht, 2006; (b) B. Pugin and H. U. Blaser,
Top. Catal., 2010, 53, 953.
8 See, e.g.: D. J. Braden, C. A. Henao, J. Heltzel,
C. C. Maravelias and J. A. Dumesic, Green Chem., 2011, 13,
1755.
9 See, e.g.: W. Luo, U. Deka, A. M. Beale, E. R. H. van Eck,
P. C. A. Bruijnincx and B. M. Weckhuysen, J. Catal., 2013,
301, 175.
10 For recent reviews on heterogeneous bifunctional catalysts,
see: (a) M. J. Climent, A. Corma and S. Iborra, Chem. Rev.,
2011, 111, 1072; (b) P. Li and H. Yamamoto, Top. Organo-
met. Chem., 2011, 37, 161; (c) P. Barbaro, F. Liguori,
N. Linares and C. Moreno-Marrodan, Eur. J. Inorg. Chem.,
2012, 3807.
Acknowledgements
Thanks are due to Dr Marco Carlo Mascherpa (ICCOM-CNR)
for ICP-OES analyses and to Centro Microscopie Elettroniche
(CNR, Firenze) for technical support.
11 For recent reviews, see: (a) D. Webb and T. F. Jamison,
Chem. Sci., 2010, 1, 675; (b) M. Irfan, T. N. Glasnov and
C. O. Kappe, ChemSusChem, 2011, 4, 300; (c) J. Wegner,
S. Ceylan and A. Kirschning, Adv. Synth. Catal., 2012, 354,
17; (d) N. G. Anderson, Org. Process Res. Dev., 2012, 16, 852;
(e) S. G. Newman and K. F. Jensen, Green Chem., 2013, 15,
1456.
Notes and references
1 (a) A. Corma, S. Iborra and A. Velty, Chem. Rev., 2007, 107,
2411; (b) I. T. Horváth, Green Chem., 2008, 10, 1024;
(c) M. Chalid, H. J. Heeres and A. A. Broekhuis, J. Appl.
Polym. Sci., 2012, 123, 3556.
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