Propylene polymerization catalyzed by novel supported titanium catalysts MgCl2/NaCl/DNBP/TiCl4 with different NaCl content

A series of MgCl2/NaCl/ID/TiCl4 type supported catalysts were prepared by comilling NaCl with MgCl2·nEtOH adduct and reacting the mixture with TiCl4 and internal electron donor (ID = di-n-butyl phthalate). The NaCl doped catalysts showed lower catalytic activity and higher isospecificity in catalyzing propylene polymerization. There was a marked change of the molecular weight distribution (MWD) of polymer with NaCl content. Catalyst containing 16 mol% NaCl produced PP with much broadened MWD (PDI = 13) than the undoped catalyst when TEA was used as the activator, while the TIBA activated catalyst produced PP with much narrower MWD.