Metallophosphate-supported Ziegler–Natta catalysts for ethylene polymerization

Several catalysts for ethylene polymerization were obtained by TiCl₄ deposition on a series of mixed metallophosphates at 100°C and were evaluated in suspension polymerization at 70°C and 14.6-atm ethylene pressure. Kinetic parameters of these polymerization reactions (initial activity, rate of deactivation, stability, etc.) were compared with properties of supports and catalysts themselves. Statistical analysis of the correlations between catalyst performance and properties shows that, in the case of Al-containing supports, the principal property of a catalyst influencing its activity is its specific surface area. An inverse dependence was found between catalyst activity and stability in ethylene polymerization. The presence of aluminium in the supports is essential for high catalytic activity, whereas the addition of other metals (non-transition or transition) does not influence the catalysts to any significant degree.