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Green Chemistry
Page 8 of 9
DOI: 10.1039/C5GC02621K
ARTICLE
Journal Name
The reusability of A-Hp-Br catalyst was also investigated in processing and the catalyst displays outstanding recyclability
flow condition and the results are summarized in Figure 8. and reusability. Further application of PANF-QAS in organic
After each run, 10 mL of ethyl acetate was pumped into the synthesis is on-going in this group.
system at 0.1 mL/min to regenerate the fiber catalyst. After
fifteen recycles, A-Hp-Br catalyst was still as active as the
Acknowledgements
original catalyst (Figure 8). Compared with commonly used
PTCs, the PANF-QAS catalyst has advantages of simple work-up
procedure for recovery and excellent reusability.
This work was supported by the National Natural Science
Foundation of China ( No. 21572156), (No. 21306133), Tianjin
Research Program of Application Foundation and Advanced
Technology (No. 14JCYBJC22600), National Basic Research
Program of China (2015CB856500), and Scientific Research
Fund Project of Yunnan Provincial Department of Education (No.
2014Y535).
Experimental
Typical procedure for PANF-QAS catalyzed reduction
Corresponding aldehydes, ketones, aryl azides, or benzyl
halides (4 mmol), NaBH4 (2 mmol) and A-Hp-Br (10 mol%)
were added to 15 mL of pH = 12 aqueous solution. The
solution was stirred at appropriate temperature and
monitored by TLC. After completion, the reaction was
quenched by 10% HCl aqueous solution to pH = 7 and filtered
to recycle catalyst A-Hp-Br, which was washed with ethyl
acetate (5 mL×2) and directly used for the next run. The eluted
ethyl acetate was used to extract aqueous phase of the
reaction mixture and dried over Na2SO4. Then the solvent was
evaporated (recycled) to give the products (most ones have
high purity, a few products with low purities were simply
purified through silica gel column).
Notes and references
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Typical procedure for continuous flow process
Silicone column was filled with 370 mg of catalyst A-Hp-Br ( c =
1.08 mmol/g) between flask and peristaltic pump. The catalytic
column was kept 25oC while a solution of the NaBH4 (2 mmol)
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8 | J. Name., 2012, 00, 1-3
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