Chemistry Reference
In-Depth Information
Poly(vinyl chloride) reacts with various thiols in ethylene diamine to produce monosulfide
derivatives [
165
]:
RSH
HN
2
NH
2
Cl
Cl
Cl
SR
When sulfur is added to the reaction mixture, disulfides form instead [
165
]:
RSH + S
H
2
N
NH
2
Cl
Cl
Cl
S
R
S
The thiolate ions can serve as strong nucleophiles and also as weak bases [
166
]. When poly(vinyl
chloride) is suspended in water in the presence of swelling agents and phase transfer catalysts, it
reacts with mercaptans, like 3-[
N
-(2-pyridyl)carbamoyl]-propylthiol:
HS
+
O
N
N
Cl
S
Cl
3
H
O
N
N
H
Acetoxylation of poly(vinyl chloride) can be carried out under homogeneous conditions [
167
].
Crown ethers, like 18-crown-6, solubilize potassium acetate in mixtures of benzene, tetrahydrofuran,
and methyl alcohol to generate unsolvated, strongly nucleophilic “naked” acetate anions. These react
readily with the polymer under mild conditions [
167
]. Substitutions of the chlorine atoms on the
polymeric backbones by anionic species take place by S
N
2 mechanism. The reactions can also
proceed by S
N
1 mechanism. That, however, requires formations of cationic centers on the backbones
in the rate-determining step and substitutions are in competition with elimination reactions. It is
conceivable that anionic species may (depending upon basicity) also facilitate elimination reactions
without undergoing substitutions [
167
].
Reactions of poly(vinyl chloride) with aromatic amines, amino alcohols, or aliphatic amines in
DMF solution result in both substitutions and in eliminations [
168
]. Reactions with aniline yield the
following structure [
168
]:
NH
2
n
Cl
NH
2
NH
2
