Environmental Engineering Reference
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HO
HO
O
"n
aked"Au nanoparticles
H
2
O/O2
O
CO2
-
OH
HO
HO
HO
HO
OH
OH
+HO
-
-H
2
O
2
-[Au]
*
OH
OH
O
R
R
R
O
2
[A u]
O
-
O
H
H
H
O
-
[Au]
-
O
-
O
-
[A u]
Scheme 8.4
Probable reaction pathway of liquid-phase glucose oxidation reaction.
Considering the reaction mechanism of the gold-catalyzed oxidation of
glucose discussed in the above section, the following points are noticeable:
1. Monometallic gold particles are active in the presence of
alkali.
2. Unsupported gold nanoparticles have a similar mechanism
to that of supported catalyst, however, the supported gold
catalyst is stable for a longer time than the “naked” particles.
3. Hydrogen peroxide instead of water is the byproduct of
gluconate.
8.5 Alcohol Oxidation
Selective oxidation of alcohol to aldehyde or ketone is an important chemical
transformation in the i ne chemical industry. h e worldwide annual pro-
duction of carbonyl compound is above 10 million tons [116]. According
to Global Industry Analysts, 1.26 million tons of aldehyde were produced
in the year 2012. Since application of stoichiometric inorganic and organic
oxidizing agents such as chromium (VI), permanganate, peracid, etc., is not
acceptable any more from an environmental and economic point of view,
there has been a growing demand for alternative green oxidation technol-
ogy for alcohol oxidation reaction. Molecular O
2
plays an important role as
an oxidizing agent in this respect. Its advantages are ready availability and
low cost; and O
2
is an eco-friendly gas that produces water as a side product
compared with inorganic oxidant which produces toxic waste.
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