Phase‐transfer catalytic activity of phosphonium salts bound to microporous polystyrene resins by long spacer chains

Supports of polystyrene with long spacers were prepared by bromoalkylation of microporous, crosslinked polystyrene resins with ω‐bromoalkenes using CF 3 SO 3 H as catalyst. The dependence of the phase‐transfer catalytic activity of phosphonium salts bound to the polystyrene resins by long spacer chains, derived from the bromoalkylated polystyrene resins, on the percentage of ring substitution, on the degree of crosslinking, and on spacer‐chain length was studied. The high activity of the catalyst with long spacer chains was explained by the increased reactivity of the active site, induced by the increased lipophilicity of the catalyst, and by the facilitated ion exchange which was brought about by an increased distance between the active site and the polymer backbone.