Biocide polymers, 19. Modification of carboxyl groups containing resins with 3(5)-methylpyrazole

Polymeric inhibitors of nitrification have been prepared by reversible attachment of 3(5)-methylpyrazole to poly(acrylic acid-co-divinylbenzene) and poly(4-vinylbenzoic acid-co-divinylbenzene) containing 86 mol-% and 88 mol-% carboxyl groups, respectively. Pyrazolide bonds between the bioactive agent and crosslinked copolymers were formed by means of aminolysis of reactive derivatives of the resins containing mixed anhydride groups or acid chloride groups. The modified resins had pendantly bound 3(5)-methylpyrazole residues in the range of 7 to 36.4 wt.-% and were subjected to hydrolysis in order to study the influence of crosslinking on the release rate of the active ingredient. The results obtained were discussed.