202
7 C–C Bond Formation via Carbocations in the Methane …
Table 7.7
Catalytic activities for the conversion of methane in the presence of ethylene over ZSM-5 exchanged with various metal cations (Reprinted from ref.
[75], Copyright 2020, with permission from Elsevier)
Metal ion a
Ag
Mo
In
Fe
V
Ga
Pd
Pb
La
Zn
Cu
H b
Conversion/%
CH
4
13.2
9.5
8.1
7.9
7.6
7.0
5.5
5.4
2.5
1.8
1.7
0
C
2 H
4
86.3
80.2
97.6
88.8
94.0
97.2
95.5
78.1
93.2
88.8
97.0
93.9
Selectivity towards
hydrocarbons/% c
68.9
94.6
98.6
76.3
75.7
92.1
82.5
80.5
96.7
99.8
99.2
91.3
Composition/mol%
C
2 H
6
1.8
0.0
1.7
1.0
2.3
3.7
3.7
0.0
1.7
1.2
1.7
2.0
C
3 H
6
20.6
20.3
5.5
20.6
11.2
5.9
9.2
24.3
11.5
16.7
6.0
10.3
C
3 H
8
11.7
13.7
25.0
18.2
24.8
28.6
22.4
13.0
23.0
7.9
24.6
26.5
C
4 H
8
9.9
14.7
3.6
15.7
8.0
4.0
6.3
17.8
8.5
10.8
4.3
9.0
C
4 H
10
13.7
16.0
24.9
14.8
22.1
23.5
18.5
11.3
18.9
11.9
36.5
18.2
C
5 –C
7 hydrocarbons
12.7
14.2
13.4
13.9
11.9
7.4
8.7
14.2
10.6
12.4
8.1
11.9
Aromatic hydrocarbons
30.3
21.1
25.9
15.8
20.1
26.9
31.2
19.4
25.8
39.1
18.8
22.1
CH
4
= C
2 H
4
= 33.8 kPa, running time: 1 h, W/F:
3.6 g h mol −1
, reaction temperature
= 673 K
a
The molar ratio of metal cations to Al 3+
was 0.17
b
H (100%)-ZSM-5
c
Moles carbon in hydrocarbon products per 100 mol (CH
4
+ C
2 H
4 ) carbon converted