Polymerization of bicyclic acetals, 4. Cationic polymerization of 1,3,3‐trimethyl‐2,7‐dioxabicyclo[2.2.1]heptane

doi:10.1002/MACP.1976.021770810

Paper

Polymerization of bicyclic acetals, 4. Cationic polymerization of 1,3,3‐trimethyl‐2,7‐dioxabicyclo[2.2.1]heptane

Published Aug 1, 1976 · M. Okada, H. Sumitomo, Shinsuke Irii

Macromolecular Chemistry and Physics

Q2 SJR score

7

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0

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Abstract

The polymerization of 1,3,3-trimethyl-2,7-dioxabicyclo[2.2.1]heptane (1) was carried out in methylene chloride, toluene, and 1-nitropropane at temperatures between −78 and 0°C. Borontrifluoride etherate, triethyloxonium tetrafluoroborate, antimony pentachloride, and iodine were used as initiators. Irrespective of the solvents and initiators used, the products at 0°C were white powders with melting points of 50—55°C, while those obtained at lower temperatures were sirups. The number average molecular weights of the unfractionated products ranged from 400 to 600. The molecular weight distribution of the oligomers prepared at 0°C was broad, in contrast to the relatively narrow distribution for those obtained at −40°C. On the basis of the determination of the hydroxyl group and unsaturated bond of the oligomers, along with the hydrogenolysis of 1, the structure of the oligomers and the mechanism of their formation are discussed. 1,3,3-Trimethyl-2,7-dioxabicyclo[2.2.1]heptan (1) wurde bei −78 bis 0°C in Methylenchlorid, Toluol bzw. 1-Nitropropan polymerisiert. Bortrifluoridatherat, Triathyloxoniumtetrafluorborat, Antimonpentachlorid und Jod wurden als Initiatoren verwendet. Unabhangig von den jeweils benutzten Initiatoren und Losungsmitteln wurden bei 0°C weise puderformige (Schmp.: 50—55°C) und bei niedrigeren Temperaturen sirupose Produkte erhalten. Die Molekulargewichtszahlenmittel der unfraktionierten Oligomeren lagen im Bereich von 400 bis 600. Die Molekulargewichtsverteilung der bei 0°C hergestellten Oligomeren war, im Gegensatz zu der verhaltnismasig engen Verteilung der bei −40°C erhaltenen Oligomeren, relativ breit. Ausgehend von der Bestimmung der Hydroxylund Doppelbindungszahlen der Oligomeren sowie der Hydrogenolyse von 1, wird die Struktur der erhaltenen Oligomeren und der Mechanismus ihrer Entstehung diskutiert.

Study Snapshot

Polymerization of 1,3,3-trimethyl-2,7-dioxabicyclo[2.2.1]heptane in methylene chloride, toluene, and 1-nitropropane produces white powders with melting points of 50-55°C and sirups at lower temperatures,

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Polymerization of bicyclic acetals, 4. Cationic polymerization of 1,3,3‐trimethyl‐2,7‐dioxabicyclo[2.2.1]heptane

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