Chemistry Reference
In-Depth Information
O
O
H
OR
Na
R
C
N
C
NC
O
Al
+
NC
O
H
OR
O
H
O
H
OR
R
C
N
C
NC
O
Al
Na
+
NC
O
OR
in the second step hydrogen and dialkoxyaluminum group are transferred:
Na
N
C
O
O
H
O
H
OR
R
C
N
Al
C
NC
O
RO
OR
OR
Al
O
H
O
O
Na
R
C
N
C
NC
NC
H
O
+
The third step is propagation. It consists of addition of a unit to the chain end and takes place upon
reaction of the terminal acyl lactam with a sodium salt of 2(dialkoxyaluminoxy)-1-azacycloheptane
shown above [
143
].
5.9.3 Hydrolytic Polymerization of Lactams
This polymerization can be looked upon as a special case of cationic polymerization. It is particularly
true when weak acids are added to the reaction mixture, as is often the case in industrial practice. In
hydrolytic polymerizations of lactams initiated by water, the hydrolysis-condensation equilibria
determine the concentrations of the amine and the carboxylic acid groups. Both functional groups
participate in the propagation reactions:
H
H
NC
H
2
O
O
NH
2
+
C
O
O
O
C
+
N
H
2
O
C
OH
+
H
2
N
H
O
OH
O
OH
C
OH
+
H
2
N
C
O
H
2
O
+
C
N
C
O
