POLYMER-SUPPORTED REAGENTS FOR MOLECULAR SEPARATIONS

A Hammett study of the complexing abilities of various polymer-supported reagents for phenols, anilines, and benzoic acids is described. For each polymeric reagent, the percent absorbed of each family of compounds is correlated with the Hammett substituent constants. A carboxylic acid resin shows no interaction with phenols and benzoic acids; only a weak interaction with anilines is found since 25% of each is absorbed regardless of the substituent present on the aromatic ring. This contrasts with the strong interaction displayed by the sulfonic resin and the moderate interaction of the phosphinic resin. Phosphonic and phosphonate monoester resins absorb increasing amounts of anilines as their basicity increases. The purely coordinating- phosphonate diester resin absorbs uniformly low levels of the three families of compounds with no substituent effect on the percent absorbed. The sulfonic resin quantitatively absorbs the anilines within the temperature range 6 to 40 C while the phosphinic resin absorbs decreasing levels within the same range. The phosphinic resin is more selective than the sulfonic resin under competitive conditions