Propylene Polymerization Over Titanium-Magnesium Catalyst: Effect Of Hydrogen On The Content Of Active Centers With Different Stereospecificity And Their Reactivity In Propagation Reaction

This paper presents data on the number of active centers (C-P(i)) with different stereospecificity and the values of propagation rate constant (k(P)(i)) for these centers in the propylene polymerization over supported titanium-magnesium catalyst in the presence or absence of hydrogen. The indicated data were obtained by quenching the polymerization with radioactive carbon monoxide ((CO)-C-14) with subsequent fractionation of the produced polymers by the TREF method into separate fractions differing in stereospecificity and estimation of the C-P(i) and kP(i) values, which determine the formation of these fractions. The propagation rate constants calculated for active centers with different stereospecificity increase in the following order: k(P)(aspecific) approximate to k(P)(low isospecific) < k(P) (isospecific) < k(P)(highly isospecific).