Electron‐exchange polymers. VII. The ion‐exchange and electron‐exchange behavior of hydrophilic hydroquinone copolymers

Countercurrent experiments on two types of sulfonated, water‐swellable, ion‐and electron‐exchange resins were performed. One type contained as commonomers vinyl‐hydroquinone, alpha‐methylstyrene, and divinylbenzene. The other type contained vinylpyridine in addition to the other comonomers. Both types demonstrated rapid, reversible cation exchange with satisfactory capacity, and reversible, slow electron exchange with acid KI and acid Br2. The electron‐exchange capacity was high. The reactions were reversible up to a pH of at least 4.7. At high pH (8.5), slow, irreversible changes occurred. Even at low pH, the resins were gradually broken down by such oxidants as ceric and ferric ions. The cation‐ and electron‐exchange equilibria were shown to be without appreciable effect on one another. Ferricyanide failed to oxidize the reduced form of such resins quantitatively, presumably because of its low potential. Interpretation of the behavior of the resin‐containing vinylpyridine was more difficult, due to the increased complexity, but nevertheless a reasonable amount of base exchange, as well as acid exchange, was demonstrated. Some possible improvements in the stability of these substances at high pH and toward other oxidants, are proposed.