Novel binary chlorides containing TiCl3 as components of coordination catalysts for ethylene polymerization. II. Behavior of the resulting catalyst systems

Binary chlorides described in part I yielded very active catalyst systems for HDPE synthesis when they were associated with (i-C₄H₉)₃Al. Very high initial polymerization rates were observed for systems bases on MnCl₂·TiCl₃, MnCl₂·2TiCl₃, or FeCl₂·2TiCl₃ (III), but high yields, i.e., above 30 kg polymer/g Ti, could be reached only using moderate pressure of ethylene. Hydrogen consumption during ethylene polymerization was observed in the case of catalysts based on AlCl₃·3TiCl₃, CrCl₃·3TiCl₃, and other binary chlorides containing elements of the VIII group. Relevant amounts of ethane were found in the case of systems III, V, and VIII. All the mixed chlorides studied were able to reduce cyclohexene in the presence of H₂ and (i-C₄H₉)₃Al, even though with different kinetic courses. Compounds II, III, V, and VIII and (MgCl₂)_1.5·TiCl₃ and AlCl₃·3TiCl₃ were very active. The results have been explained on the basis of solubilization processes involving the heterogeneous catalysts which actually were experimentally verified during cyclohexene reduction. Analogous processes may occur also during HDPE synthesis.