Special features of the bulk polymerization of propylene on a titanium-magnesium catalyst in the presence of hydrogen

Abstract

The polymerization of propylene in a compressed monomer medium on a modified titanium-magnesium catalyst in the presence of hydrogen is studied. It is established that the introduction into the reaction medium of a relatively small quantity of hydrogen (up to 5 × 10 −3 mole/litre) enables the catalytic activity of the system under study to be increased by a factor of 3–5. It is shown that the non-steady-state character of the bulk polymerization of propylene in the presence of hydrogen is associated with the progress of bimolecular destruction of active centres in the reaction system. The chain structure of the atactic polypropylene fractions synthesized on a titanium-magnesium catalyst and microspherical σ-TiCl 3 in the presence of AlEt 3 is studied by 13C NMR. Analysis of the results indicates the close nature of the non-stereospecific active centres of the given catalytic systems.