Table 2 Comparison of catalyst precursor activity in metathesis of propane at 150
C for 120 h
No.
Catalyst precursors
TON
a
Product selectivity (%)
b
CH
4
C
2 H
6
C
4 H
10
i-C 4 H
10
C
5 H
12
i-C 5 H
12
C
6 H
14
1
[ (
SiO)Ta(¼CH
t
Bu)(CH
2
t
Bu)
2 ]
(Si-700) (29)
35
12.8
47.5
22.8
10.4
3.5
2.5
Traces
2
[ (
Al s O)Ta(¼CH
t
Bu)(CH
2
t
Bu)
2 ]
(Al2O3-500) (30)
34
5.0
52.0
32.0
7.0
3.5
1.5
Traces
3
[ (
SiO)Ta(¼CH
t
Bu)(CH
2
t
Bu)
2 ]
(SA-500) (31)
33
10.5
47.0
31.2
3.8
4.2
2.3
Traces
4
[ (
SiO)W(C
t
Bu)(CH
2
t
Bu)
2 ]
(Si-700) (21)
<1
–
–
–
–
–
–
–
5
[(Al
s O)W(C
t
Bu)(CH
2
t
Bu)
2 ]
(Al2O3-500) (23)
28
2.7
65.4
20.7
2.9
5.3
1.5
1.0
6
[ (
SiO)W(C
t
Bu)(CH
2
t
Bu)
2 ]
(SA-500) (32)
29
1.6
61.7
25.7
3.4
5.5
1.3
1.0
7
[ (
SiO)Ta–H] (Si-700) (33)
60
10.0
46.0
30.6
5.1
4.8
2.2
Traces
8
[ (
Al s O)Ta–H]
(Al2O3-500) (34)
60
9.5
47.5
27.9
8.6
4.5
1.5
–
9
[ (
SiO)Ta–H] (SA-500) (35)
59
11.5
46.5
31.4
4.1
4.8
2.2
–
10
[(SiO)W–H]
(Si-700) (36)
8
5.7
56.0
29.0
2.8
5.1
1.4
–
11
[(Al
s O)W–H]
(Al2O3-500) (24)
121
2.4
57.3
28.9
3.7
5.0
1.3
1.4
12
[(SiO)W–H]
(SA-500) (37)
123
1.9
58.0
28.9
3.2
5.2
1.4
1.4
13
[(SiO)TaMe
4 ]
(Si-700) (13)
49
11.6
45.4
32.8
6.5
5.5
1.7
1.0
14
[(SiO)WMe
5 ]
(Si-700) (27)
127
2.0
54.0
33.0
4.0
6.0
1.0
Traces
a
TON is expressed in (mol of propane transformed)/(mol. of W)
b
The selectivities are defined as the amount of product over the total amount of products
174
M.K. Samantaray et al.