296
5 – Applications
The overall reaction is
C 4 H 8 + 6O 2 $ 4CO 2 + 4H 2 O
2 Partial electrochemical oxidation
• at the anode
C n H m + n
m
2
+
^
hO 2− $ nCO +
m
2 H 2 O + (2n + m)e
• at the cathode
n
m
2
4
+
^
hO 2 + (2n + m)e $ n
m
2
+
^
hO 2−
The overall reaction is
C n H m +
n
m
2
4
+
^
hO 2 $ nCO +
m
2 H 2 O
Applied to propane
• at the anode
C 3 H 8 + 7O
2−
$ 3CO + 4H 2 O + 14e
• at the cathode
2
7
O 2 + 14e $ 7O
2−
The overall reaction is
C 3 H 8 + 2
7
O 2 $ 3CO + 4H 2 O
Applied to but-2-ene
• at the anode
C 4 H 8 + 8O
2−
$ 4CO + 4H 2 O + 16e
• at the cathode
4O 2 + 16e $ 8O
2−
The overall reaction is
C 4 H 8 + 4O 2 $ 4CO + 4H 2 O
c. Cell emf ΔE
2 For a hydrocarbon C n H m
• total electrochemical oxidation
E
E
(4n m)F
RT
ln P
P
P
P
C H /CO
CO
n
H O
m/2
C H
O
n (m/4)
n m
2
2
2
n m
2
Δ
Δ
=
+
+
+
#
#
#
°
• partial electrochemical oxidation