Infrared spectrum of cationically produced polypropylene

Structure of Cationic Propene, 1-Butene, and cis-2-Butene Polymers. Mechanism of the Polymerization

“…The olefin analyses, again, gave valuable information about the olefin-forming termination steps. The backbone analyses confirmed the basic conclusions of previous IR studies3, 4 that polypropenes and poly-1-butenes have very irregular structures with short branches but differed in the details. Finally, we have also conducted kinetic and molecular weight studies.…”

“…Table I), we believe that path 3 is the most frequent in the termination. To explain the formation of the vinylidene olefins, paths 4 and/or 5 are suggested. In path 4, the penultimate propene addition is not followed by a hydride rearrangement.…”

“…Fontana was the first to recognize24 that cationic polypropenes have a "treebranched" skeleton as a result of hydride transfer reactions during propagation. Subsequently, Ketley and Harvey3 and Immergut et al 4 have reported on the basis of IR studies that cationic polypropenes do not have the regular [-CH2CH(CH3H" skeleton but contain ethyl and propyl branches. To account for their formation, both interand intramolecular hydride shifts were postulated.3 To find out more details about the polymer skeleton, we applied a combination of 13C NMR and IR studies.…”

Cryosynthesis of catalysts for propylene oligomerization based on titanium tetrachloride and magnesium

“…An ohgomer characterized by a similar spectrum has been obtained over the Ziegler catalyst TiCI4_AIBui2CI. 15 The spectrum of the oligomer formed in the presence of catalyst 2 is typical of the products of The difference in the mechanisms of propylene conversion in the presence of catalysts 1 and 2 is also confirmed by a change in the molecular-weight distribution of the oligomers. A wax-like oligomer containing -25% of heavy products is formed in the presence of catalyst 1 (M > 103), whereas only low-molecular oils are formed in the presence of catalyst 2 regardless of the TiCI 4 : Mg ratio.…”