Chemistry Reference
In-Depth Information
place at conversions of 45-50% [
205
]. These rates are favorably influenced by increases in the
dielectric constants of the solvents [
204
]. Two different rate constants also exist in reactions with 3-
alkylaminopropionitrile.
9.4.3.4 Friedel-Craft Alkylation Reactions
Friedel-Craft acylations of polystyrene can be carried out in CS
2
or in CCl
4
at reflux temperatures of
the solvents. The yields are high [
209
]:
O
catalyst
+
Cl
O
Chloromethylated copolymers of styrene with divinyl benzene undergo Friedel-Craft type
reactions in condensations with 1-phenyl-3-methylpyrazolone or with 1-phenyl-2,3-dimethyl-
pyrazolone-5 in the presence of either ZnCl
2
,BF
3
, or SnCl
4
[
208
]:
O
N
N
+
CH
2
Cl
O
N
N
Polystyrene can also cross-link by a Friedel-Craft reaction [
210
]:
CH
2
Cl
ClCH
2
+
SnCl
4
