Anionic Polymerisation of Alkylene Oxides Catalysed by Phosphazenium Compounds

2 Anionic Polymerisation of Alkylene Oxides Catalysed by Phosphazenium Compounds 

Phosphazenium compounds are a new class of catalyst that are extremely efficient in the anionic polymerisation of PO and EO, initiated by hydroxyl groups [34-38, 144-146]. 

To explain the catalytic mechanism of the alkylene oxide polymerisation with phosphazenium compounds, several considerations concerning the peralkylated polyamino-phosphazenes should be made. 

The reagent of the year in 1992 was one of the strongest organic bases, called the Schwesinger reagent [147]  

The question is why are these phosphazene compounds very strong bases that are comparable with alkali hydroxides  

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