Chemistry Reference
In-Depth Information
The material cyclodimerizes on exposure to light [
261
] (see Chap.
10
for additional discussion of
this subject).
Schotten-Baumann esterifications
of poly(vinyl alcohol) are used extensively in preparations of
various derivatives. The reactions appear to proceed well when acid chlorides are employed in two-
phase systems [
262
]. The polymers are dissolved in water and the solutions are blended in 1:1:1 equal
volume with NaOH solutions and cyclohexanone. They are then mixed thoroughly with solutions of
the acid chlorides in mixtures of cyclohexanone and toluene. The reaction mixture is stirred
vigorously for about 90 min at
5to5
C to obtain the desired product.
Metalation
of poly(vinyl alcohol) is used to form ether derivatives [
263
]:
+
+
O
S
O
S
Na
OH
ONa
+
Br
+
NaBr
x
ONa
O
x
on poly(vinyl alcohol) yields soluble products. Only some of the hydroxyl
groups, however, are converted to amide structures [
264
]:
The
Ritter reaction
RCN
H
2
SO
4
H
N
OH
OH
OH
O
R
Also, it is possible that neighboring group interactions may lead to cyclizations and formations of
1,3-oxazines [
264
].
9.4.6 Miscellaneous Exchange Reactions
Many miscellaneous exchange reactions are reported in the literature. A few are presented here. One
such reaction is reduction of pendant carbonyl groups of poly(vinyl methyl ketone) with metal
hydrides [
242
,
265
]:
LiAlH
4
or KBH
4
O
R
HO
R
