Study of the MgCl2 recrystallization conditions on Ziegler-Natta catalyst properties

Magnesium dichloride supported titanium catalysts were prepared by dissolvi ng anhydrous MgCl2 in 1-hexanol/isooctane. Then recrystallization took plac e through different techniques such as evaporation of the solvent, quick co oling, precipitation with silicon tetrachloride and precipitation with tita nium tetrachloride. The FT-IR analysis showed that several degrees of dealc oholation took place as a result of the adducts of MgCl2. XROH. Moreover, i t was found that the most active catalysts in the polymerization of ethylen e were those obtained recrystallizing MgCl2 by precipitation with SiCl4. On the other hand, those directly recrystallized with TiCI4 were the least re active and the ones that produced polyethylenes with the highest molecular weights and the lowest degrees of crystallinity.