Layer-lattices in Ziegler–Natta catalysts

Some layered inorganic compounds of interest in old and new polymerization processes by Ziegler-Natta stereospecific catalysis have been studied. The results are reported of an investigation concerning the crystallographic disorder phenomena in α-TiCl3, VCl3, FeCl3, ball-milled α-MgCl2, β-MgCl2, and in a new catalytic system produced according to some recent trends in the field. Best fits are reported of the experimental x-ray diffraction patterns with patterns calculated for a theoretical model that accounts for structural disorder; the different fits indicate that disorder phenomena due to stacking faults are rather frequent in the examined compounds. The catalytic systems are more and more dispersed, and the maximum of dispersion in heterogeneous systems is reached for the recently proposed formulations.