PROCESS FOR THE PREPARATION OF POLYOLEFINS

1355564 Olefin polymerization catalyst FARBWERKE HOECHST AG 2 Sept 1971 [2 Sept 1970] 40991/71 Heading C3P An olefin polymerization catalyst comprises (A) the hydrocarbon-insoluble reaction product of a halogen-free titanium (IV) alkoxide and a silicon tetrahalide with a halogen-free hydroxylcontaining compound of magnesium, and (B) an organometallic compound of a metal of Groups IA, IIA or IIIB. An alkoxide of aluminium or silicon may also be present during the preparation of component (A). 'Component (A) may be treated with an organometallic compound prior to polymerization, washed, and then activated with a furtheramount of an organometallic compound when needed. Suitable support materials include (MgOH) 2 , the basic carbonate prepared from a soluble magnesium salt and an alkali metal carbonate, the basic sulphate obtained by drying a MgO-MgSO 4 cement, and compounds obtained by reacting MgO with less than an equivalent amount of water or an acid, e.g. phosphoric acid or acetic acid. Examples describe the liquid- or gas-phase polymerization of ethylene and/or propylene using (A) the reaction product of Ti(O-Pi-i) 4 , Ti(O-Bu-i) 4 or and SiCl 4 with a suitable support, in some cases in the presence of Al(O-Pr-i) 3 or Si(O-Pr-i) 4 and (B) AlEt 3 or aluminium isoprenyl. The use of MgSO 4 or MgCO 3 as the support and of BCl 3 , PCl 3 or SnCl 4 instead of SiCl 4 is also described for comparison.