Chemistry Reference
In-Depth Information
Table 3.2 Ruthenium-catalyzed
aerobic
oxidation
of
benzyl
alcohol
to
benzaldehyde.
Ru catalyst
OH
O
d
n
4
r
4
n
g
|
0
O
2
Solvent TOF (h
1
) Yield (%)
Catalyst
T (K)
Selectivity (%)
1.4% Ru/Al
2
O
3
356
PhCF
3
40
498
499
RuO
2
xH
2
O
353
PhCH
3
1.4
16
100
10% RuO
2
/FAU zeolite
353
PhCH
3
8.5
499
499
Ru
0.35
MnFe
1.5
Cu
0.15
O
x
295
PhCH
3
3.4
95
100
Ru
0.3
Co
2
CeO
x
333
PhCF
3
10
499
499
Ru-Mg-Al-hydrotalcite
333
PhCH
3
1.1
95
97
Ru-Co-Al-hydrotalcite
333
PhCH
3
9.3
96
96
Ru
31
-hydroxyapatite
353
PhCH
3
2
499
499
[RuCl
2
(p-cymene)]
2
/C
383
PhCH
3
4.7
92
-
RuO
4
/polymer
348
PhCH
3
20
495
100
NR
3
1
RuO
4
/MCM-41
353
PhCH
3
170
100
100
Pr
4
N
1
RuO
4
/ormosil (SiO
2
)
348
PhCH
3
13
100
100
The selective oxidation of various alcohols to their corresponding alde-
hydes and ketones was achieved by ruthenium species stabilized on nano-
crystalline magnesium oxide (NAP-MgO) by the incorporation of choline
hydroxide, a basic ionic liquid, with excellent yields.
112
The catalyst can be
used for four cycles with almost constant activity.
3.3 Concluding Remarks
The current trend towards the production of chemicals from feedstocks
based on renewable resources rather than fossil fuels such as oil or natural
gas has also led to a need for effective methods for the conversion of
carbohydrates, from glycerol to polysaccharides, to commercially valuable
products. One would expect ruthenium to be a good candidate for catalyzing
selective and environmentally benign aerobic oxidation reactions of alcohols
and also amines, alkenes and alkanes and, as reviewed in this chapter,
considerable progress has been made in the development of synthetically
useful ruthenium-catalyzed oxidation reactions. However, there are still
many goals to be achieved and it remains a fascinating and challenging area
of research.
.
References
1. I. W. C. E. Arends and R. A. Sheldon, in Modern Oxidation Methods,
ed. J.-E. B¨ckvall, Wiley-VCH, Weinheim, 2004, pp. 83-118.
2. I. W. C. E. Arends and R. A. Sheldon, in Modern Oxidation Methods,
ed. J.-E. B¨ckvall, Wiley-VCH, Weinheim, 2nd edn, 2010, pp. 147-185.
3. Advances in Oxygenated Processes, ed. A. L. Baumstark, JAI Press,
London, 1995.
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