6 Catalysis with MNPs on N-Doped Carbon
207
NO 2
Co 3 O 4 /NGr@C (1 %)
50 bar H 2 , 110°C
THF/H 2 O, 4-12h
R
NH 2
R
>30 Examples
Up to 99% yield
Scheme 6.8 Hydrogenation of nitro compounds using Co 3 O 4 -NGr@C catalyst
Co 3 O 4 /NGr@C
125°C, 50 bar H 2 ,
THF-H 2 O (10:1), 24h
R 1
NO 2
R 2
CHO
+
R 1
H
N
R 2
H
N
Br
H
N
H
N
H
N
Cl
Cl
Cl
EtO
N
H
MeO
N
S
H
N
N
H
S
H
N
O
64 %
64 %
59 %
65 %
75 %
94 %
48 %
71 %
Scheme 6.9 One-pot reductive amination for synthesis of amines using Co 3 O 4 /NGr@C catalyst
1 bar O2, 0.2 Equiv. K2CO3
60
o
C, 24 h
OH
O
O
CH 3 OH
+
R
R
Co3O4/NGr@C (2.5 mol%
(2.5 mol% Co)
1 bar O2, 0.5 Equiv. K2CO3
n-Heptane, 70-110
0 C, 24 h
OH
O
R /
O
+
R
R
OH
R /
R
/
-OH= aliphatic alcohol
Co3O4/NGr@C
(2.5 mol% Co)
OH
O
O
R
R
R
1 bar O 2 , 1 Equiv. K 3 PO 4
n-Heptane, 110
0 C, 24 h
Co3O4/NGr@C
(2.5 mol% Co)
R
1 bar O2, 1 Equiv. K3PO4
n-Heptane, 90-120
0 C, 24 h
OH
R = aliphatic
R
O
O
R
Co3O4/NGr@C
(3 mol% Co)
13 Examples
Up to 92% yield
4 Examples
Up to 85 % yield
6 Examples
Up to 75% yield
>40 Examples
Up to 97% yield
Scheme 6.10 Co-catalyzed direct oxidative esterification of alcohols to esters
procedures [17] using toxic cyanides, while the simple ones are produced by ammoxidation processes in the gas phase [18]. Compared to these traditional processes,
the synthesis of nitriles from alcohols and ammonia is considered to be greener
and a more convenient process for the preparation of nitriles. Advantageously
Co 3 O 4 /NGr@C empower the synthesis of >80 functionalized and structurally diverse
aromatic, heterocyclic, allylic and aliphatic nitriles (Scheme 6.11) [5].
Unfortunately, the use of carbon supported cobalt nanoparticles prepared by
the immobilization and pyrolysis of nitrogen ligated Co-complexes is limited to