Ring-Ring and Ring-Chain Equilibration of Dimethylphosphazenes. Relation to Phosphazene Polymerization

Harry R. Allcock, D. B. Patterson

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Hexamethylcyclotriphosphazene, [NP(CH 3 ) 2 ] 3 , and octamethylcyclotetraphosphazene, [NP(CH 3 ) 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.

Original languageEnglish (US)
Pages (from-to)197-200
Number of pages4
JournalInorganic Chemistry
Volume16
Issue number1
DOIs
StatePublished - Jan 1 1977

Fingerprint

Dimethylpolysiloxanes
phosphazene
Polymers
polymerization
Molecular weight
Polymerization
Acids
rings
methylidyne
high polymers
low molecular weights
trimers
acids

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

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abstract = "Hexamethylcyclotriphosphazene, [NP(CH 3 ) 2 ] 3 , and octamethylcyclotetraphosphazene, [NP(CH 3 ) 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.",
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Ring-Ring and Ring-Chain Equilibration of Dimethylphosphazenes. Relation to Phosphazene Polymerization. / Allcock, Harry R.; Patterson, D. B.

In: Inorganic Chemistry, Vol. 16, No. 1, 01.01.1977, p. 197-200.

Research output: Contribution to journalArticle

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T1 - Ring-Ring and Ring-Chain Equilibration of Dimethylphosphazenes. Relation to Phosphazene Polymerization

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AU - Patterson, D. B.

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AB - Hexamethylcyclotriphosphazene, [NP(CH 3 ) 2 ] 3 , and octamethylcyclotetraphosphazene, [NP(CH 3 ) 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.

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