As a rule, dimethylpentenes are produced mainly from isobutene, while
methylhexenes tend to originate from n-butenes.
The relative yield of heptenes is illustrated in Fig. 8 as a function of the olefinic
feed composition; as expected, higher yields of heptenes are obtained when the feed
Table 8 Major isomers in the heptene fraction (>0.1 wt.% approx)
No.
Component
Wt%
Boiling point (
C)
1
4,4-Dimethyl-1-pentene
0.8
72.5
2
4,4-Dimethyl-trans-2-pentene
4.4
76.8
3
3,3-Dimethyl-1-pentene
0.2
77.6
4
4,4-Dimethyl-cis-2-pentene
0.1
80.4
5
3,4-Dimethyl-1-pentene
0.2
81.1
6
2,4-Dimethyl-1-pentene
6.2
81.7
7
2,4-Dimethyl-2-pentene
16.5
83.4
8
2,3-Dimethyl-1-pentene
7.8
84.3
9
5-Methyl-trans-2-hexene
1.0
86.1
10
2-Methyl-trans-3-hexene
0.2
86.1
11
3,4-Dimethyl-trans-2-pentene
16.3
87.2
12
3,4-Dimethyl-cis-2-pentene
4.4
87.2
13
3-Methyl-1-ethyl-1-butene
3.1
88.9
14
3-Methyl-trans-3-hexene
0.5
93.6
15
3-Methyl-trans-2-hexene
1.5
93.9
16
3-Methyl-cis-2-hexene
2.9
93.9
17
3-Methyl-cis-3-hexene
2.2
95.3
18
2-Methyl-2-hexene
2.2
95.4
19
3-Ethyl-2-pentene
1.2
96.0
20
2,3-Dimethyl-2-pentene
27.5
97.4
21
Trans-2-Heptene
0.6
97.9
22
Cis-2-Heptene
0.1
98.5
heptene yield
isobutene
mixed butenes
n-butene
100
80
60
40
20
0
% propylene in olefins
Fig. 8 Effect of olefin
composition on heptene
yields
Olefin Condensation
473