Chemistry Reference
In-Depth Information
Table 7.3
Compositions of telomers
X
Fraction (%)
1
5
2
44
3
28
4
15
>
4 8
From Nesmeyanov and Reundlina [
66
], by permission of
Tetrahedral Letters, Elsevier Science, Ltd
carried out at 120-200
C temperature and 400-600 atmospheres pressure. The preferred chain-
transferring agents for this reaction are CCl
4
and COCl
2
[
66
]:
CCl
4
+
R
R
C
+
R
CH
2
Cl
CCl
3
2
Cl
+
CCl
4
CCl
3
Cl
Cl
Cl
Cl
CH
2
Cl
Cl
x-1
4
The resultant chloro alkanes are then hydrolyzed with sulfuric acid:
Cl
Cl
H
2
SO
4
H
2
O
O
Cl
Cl
Cl
x
x
HO
After hydrolyses, the products are treated with ammonia:
O
Cl
NH
3
O
NH
3
x
HO
x
O
The amino acid is condensed to a lactam and subsequently polymerized. Table
7.3
shows the
composition of the telomers in the above free-radical polymerization [
66
]. As seen from the table, the
economics of producing nylon 7 by this process is not as favorable as one may wish. An advantage,
however, to producing nylon 7 is that the polymer contains little monomer and can be spun without
washing or extraction, as is required with nylon 6.
An early synthesis of
nylon 8
used cyclooctatetraene that was formed from acetylene and then
converted to
nylon 8
as follows:
[H]
[O]
4
O
NOH
O
weak base
Beckmann
rearrangement
H
2
SO
4
O
etc.
N
