Hexamethylcyclotriphosphazene, [NP(CH3)2]3, and octamethylcyclotetraphosphazene, [NP(CH3)2]4, participate in a ring-ring equilibration between 200 and 350 °C, but they do not polymerize. A ΔH value of 10.2 kcal and a ΔS value of 14.3 eu were determined for the tetramer-trimer interconversion. The equilibration is inhibited by base. Acids accelerate equilibration and also yield linear low molecular weight compounds: these species cyclize to III and IV when heated. The results are compared with the ring-high polymer and ring-ring interconversions in the halogenophosphazene, dimethylsiloxane, dimethylsilthiane, and polysulfur series.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry