Low-Temperature Polymerization of endo- and exo-2-Methyl-7-oxabicyclo-[2.2.1]-heptane

Abstract

Polymerization of the title compounds in methylene di-chloride with PF, catalyst have shown that the rate of polymer formation drops sharply with temperature and the polymerization ceases entirely around -60 to -70°C. Ex-periments carried out with the exo-2-Me isomer have shown that at -30°C a limiting conversion of approx 40% is attained and simultaneously the molecular weight and the molecular weight distribution level off. At -50°C the same limiting conversion level is reached; however, the molecular weight level is higher and a study of changes in molecular weight distribution with time indicates that at this tempera-ture a greater proportion of chains remain active throughout the polymerization. Even at -30°C, however, experiments with changing conditions, especially the temperature, during the runs have demonstrated that the systems are not “dead” after the limiting conversion has been reached. Polymeriza-tion of the endo-2-Me isomer at -50°C has shown that in the time interval studied the limiting viscosity number increases essentially linearly with time.     

Zur Kenntniss der Aminbasen secundärer Alkohole

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Ueber die Alkaloide der Jaborandibl?tter

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Bestimmung der Salpeters?ure und Phosphors?ure auf spectralanalytischem Wege

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Elektrolytische Studien

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Bücherbesprechungen

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Eine Bemerkung zu den verschiedenen Möglichkeiten eine Zahl in einen Kettenbruch zu entwickeln

Ohne ZusammenfassungHerrn Prof. Dr. C. L. Siegel zum 40. Geburtstag.