Patent ID: 8399528

Claim:
A method for producing monodisperse ion exchangers having chelating functional groups represented by the structural formula (I) where is the polymer backbone and Y is hydrogen, sodium or potassium and A is hydrogen, CH 2 COOH, CH 2 COONa or CH 2 COOK, comprising the steps of: a) forming monodisperse crosslinked polymer beads via reacting monomer droplets of at least one monovinylaromatic compound, at least one polyvinylaromatic compound, at least one porogen and at least one initiator or an initiator combination, wherein a jetting process and/or the seed-feed process is employed, b) phthalimidomethylating the monodisperse crosslinked polymer beads with phthalimide derivatives present in inert solvent and comprising an SO 3 adduct, wherein said phthalimidomethylating comprises introducing a subportion of from 1 to 15% by weight of the monodisperse crosslinked polymer beads into the SO 3 adduct and stirring at a temperature of less or equal to 35° C. from 1 to 15 hours, wherein the amount of free SO 3 is from 0.28 to 0.5 mol based on 1 mol of phthalimide and thereafter introducing the residual amount of the monodisperse crosslinked polymer beads into the SO 3 adduct at a temperature of from 30 to 75° C., thereby forming phthalimidomethylated polymer beads, c) converting the phthalimidomethylated polymer beads to aminomethylated polymer beads, and d) reacting the aminomethylated polymer beads to introduce chelating groups, thereby forming said monodisperse ion exchangers having chelating functional groups represented by the structural formula (I).