SYNTHESIS OF POLYMERS CONTAINING THE PENDANT OXAZOLIDONE MOIETY AND THEIR COMPLEX-FORMING BEHAVIOR WITH PHENOLS

The synthesis and complex-forming behavior of a number of oxazolidone-containing crosslinked polystyrenes were investigated. Three oxazolidone-containing polymers with different spacer lengths between their main chains and the oxazolidone groups, NOBS, NOHS, and NODS, were synthesized by the reaction of cross-linked poly(styrene-co-4-(chloromethyl)styrene) with 3-(2-hydroxyethyl)-,3-(6-hydroxyhexyl)-, and 3-(12-hydroxydodecyl)oxazolidones, respectively. The complex-forming behavior of these polymers with phenols was studied in terms of the effect of the length of the spacers. The strength of the complex-forming capacity was evaluated as the binding constant (K), which was obtained by Klotz plots. K values obtained in water were larger than those in chloroform in any polymer. The K value in water increased with an increase of the methylene chain length of the spacer, whereas K values in chloroform were nearly equal in the polymers having methylene chain length n greater than or equal to 6. K values for the systems of these polymers and four phenols in chloroform depended on the acidity of the phenols. A good linear relationship between log K and the pK(a) of the phenols indicated that the interaction is strengthened in proportion to lowering the pK, of a phenol used. K values for the polymers having the oxazolidone moiety were compared with those for the polymers having the pyrrolidone moiety. A similar tendency was observed for the effect of methylene chain length and the difference in complex-forming behavior between water and chloroform. The relationship between log K and the pK(a) of phenols was also the same. However, the degree of strength of the complex-forming capacity in the oxazolidone polymers was smaller than that of the pyrrolidone polymers. This result was also discussed.