Alkaline saponification of crosslinked acrylonitrile pearl polymers to give weakly acidic ion-exchanger involves two-stage reaction at different temperatures

摘要

Alkaline saponification of crosslinked acrylonitrile pearl polymers involves: (a) saponification at temperature T 1of 70-120[deg]C until a degree of saponification of >=65% is reached; and (b) completing saponification at temperature T 2of 120-180[deg]C, with T 2being >=10[deg]C higher than T 1. An independent claim is also included for a weakly acidic ion-exchanger obtained by the saponification.