Pseudocationic complexes

Ethoxylates with six or more ethylene oxide units form pseudocationic complexes with many metals, and the tetraphenylborates of these are insoluble or sparingly soluble in water. Several volumetric methods for the determination of ethoxylates are based on this. Some of them are two-phase procedures. 

The kinetics scheme analysed in Section 2.6.4 naturally leads to formation of polymers with a most probable distribution of molar mass (cf. Section 2.4.9). However, polymers formed by cationic polymerization sometimes have complex (e.g. bimodal) molar mass distributions and in certain cases (e.g. pseudocationic polymerizations) this is thought to be due to simultaneous growth of different types of active species with very different but characteristic values of the rate constants for propagation and ion-pair rearrangement. 

---