6 Catalysis with MNPs on N-Doped Carbon
203
5 bar O 2 , 130-140
o C
+ NH 3
R
OH
Fe 2 O 3 /NGr@C
R
CN
>50 Examples
Up to 98% yield
3 bar O 2 , 110-130
o C
+ NH 3
R
NH 2
Fe 2 O 3 /NGr@C
R
CN
>50 Examples
Up to 98% yield
Scheme 6.4 Fe 2 O 3 /NGr@C catalyzed synthesis of nitriles from alcohols and amines
core/shell catalysts (FeOx@NGr-C) for oxidative dehydrogenations of several Nheterocycles (Scheme 6.5) [7].
In 2017, Balaraman et al. [8] have also prepared iron oxide nanoparticles supported
on N-doped graphene oxides by the immobilization of Fe-phenanthroline complex
on exfoliated graphene oxide (EGO) and subsequent pyrolysis at 900 °C under
argon. Applying these iron-based catalysts acceptor-free dehydrogenation of Nheterocycles, amines, alcohols has been performed to obtain valuable compounds
in good to excellent yields (Scheme 6.6) [8].
Dodelet et al. [9] have prepared carbon supported iron-based catalysts with active
sites containing iron cations coordinated by pyridinic nitrogen functionalities in the
interstices of graphitic sheets within the micropores as efficient oxygen reduction
catalysts. These catalysts are prepared from carbon support, phenanthroline and
ferrous acetate by ball-milling and then pyrolyzed twice, first in argon, then in
ammonia. This Fe-based electro-catalyst exhibits the current density of a cathode
equal to that of a platinum-based cathode with a loading of 0.4 mg of platinum per
square centimeter at a cell voltage of ≥0.9 V [9].
Apart from phenanthroline, N-aryliminopyridines have also been used as suitable nitrogen ligands for the preparation of iron nanoparticles supported on Ndoped carbon [10]. A series of N-aryliminopyridines were prepared using different
substituted anilines. In situ generated Fe complexes of these ligands were immobilized on carbon and subsequent pyrolysis produced iron-based nanocatalysts
R 1
N
R 2
FeOx@NGr-C
15 bar Air, 100-120
o C,
acetone
R 1
N
R 2
Up to 92% yield
Scheme 6.5 Oxidative dehydrogenation of N-heterocycles using Fe 2 O 3 -nitrogen doped core-shell
catalysts
H
N
R
Ion oxide@EGO
t-BuOK, Mesitylene
145
o C
N
R
+ H 2
R
NH 2
Up to 94 % yield
Ion oxide@EGO
t-BuOK, Mesitylene
145
o C
R
N
H
R + H 2
R 1
R 2 (H)
Ion oxide@EGO
t-BuOK, Mesitylene
145
o C
OH
Up to 99 % yield
R 1
R 2 (H)
O
Up to 98 % yield
+ H 2
Scheme 6.6 Iron-catalyzed acceptor-free dehydrogenation of N-heterocycles, amines and alcohols
203
5 bar O 2 , 130-140
o C
+ NH 3
R
OH
Fe 2 O 3 /NGr@C
R
CN
>50 Examples
Up to 98% yield
3 bar O 2 , 110-130
o C
+ NH 3
R
NH 2
Fe 2 O 3 /NGr@C
R
CN
>50 Examples
Up to 98% yield
Scheme 6.4 Fe 2 O 3 /NGr@C catalyzed synthesis of nitriles from alcohols and amines
core/shell catalysts (FeOx@NGr-C) for oxidative dehydrogenations of several Nheterocycles (Scheme 6.5) [7].
In 2017, Balaraman et al. [8] have also prepared iron oxide nanoparticles supported
on N-doped graphene oxides by the immobilization of Fe-phenanthroline complex
on exfoliated graphene oxide (EGO) and subsequent pyrolysis at 900 °C under
argon. Applying these iron-based catalysts acceptor-free dehydrogenation of Nheterocycles, amines, alcohols has been performed to obtain valuable compounds
in good to excellent yields (Scheme 6.6) [8].
Dodelet et al. [9] have prepared carbon supported iron-based catalysts with active
sites containing iron cations coordinated by pyridinic nitrogen functionalities in the
interstices of graphitic sheets within the micropores as efficient oxygen reduction
catalysts. These catalysts are prepared from carbon support, phenanthroline and
ferrous acetate by ball-milling and then pyrolyzed twice, first in argon, then in
ammonia. This Fe-based electro-catalyst exhibits the current density of a cathode
equal to that of a platinum-based cathode with a loading of 0.4 mg of platinum per
square centimeter at a cell voltage of ≥0.9 V [9].
Apart from phenanthroline, N-aryliminopyridines have also been used as suitable nitrogen ligands for the preparation of iron nanoparticles supported on Ndoped carbon [10]. A series of N-aryliminopyridines were prepared using different
substituted anilines. In situ generated Fe complexes of these ligands were immobilized on carbon and subsequent pyrolysis produced iron-based nanocatalysts
R 1
N
R 2
FeOx@NGr-C
15 bar Air, 100-120
o C,
acetone
R 1
N
R 2
Up to 92% yield
Scheme 6.5 Oxidative dehydrogenation of N-heterocycles using Fe 2 O 3 -nitrogen doped core-shell
catalysts
H
N
R
Ion oxide@EGO
t-BuOK, Mesitylene
145
o C
N
R
+ H 2
R
NH 2
Up to 94 % yield
Ion oxide@EGO
t-BuOK, Mesitylene
145
o C
R
N
H
R + H 2
R 1
R 2 (H)
Ion oxide@EGO
t-BuOK, Mesitylene
145
o C
OH
Up to 99 % yield
R 1
R 2 (H)
O
Up to 98 % yield
+ H 2
Scheme 6.6 Iron-catalyzed acceptor-free dehydrogenation of N-heterocycles, amines and alcohols