| 摘要 |
<p>Cation-exchange resins are provided which have improved resistance to copolymer degradation caused by oxidizing agents like molecular oxygen. The resins are prepared by functionalizing a plurality of certain cross-linked copolymer beads with cation-exchange groups. The cross-linked copolymer beads are prepared from a para-substituted monovinyl aromatic monomer comprising an aromatic ring substituted with an oxidation-stabilizing moiety in a position para to a polymerizable vinyl moiety. The oxidation-stabilizing moiety is substantially inert during substitution of the copolymer beads with the cation-exchange functional groups, which avoids substitution at the para position. Exemplary of such para-substituted monovinyl aromatic monomers are para-methylstyrene, para-ethylstyrene, and para-chlorostyrene. The cation-exchange resins are capable of being used in a separation process for longer periods of time without detrimental increases in bed pressure drops, loss of operating capacity, and leaching of organic contaminants.</p> |
