Catalysts for stereospecific polymerisation of (alpha)-olefins - prepd. by redn. of titanium tetrachloride in four stage process

摘要

Catalytic elements are prepd. by (a) reducing TiCl4 with a reducing agent of formula (I): AlRnX3-n (I) (where R= 1-18C hydrocarbon gp.; X= halogen, n is any no. such that 0 n3) or with metallic Al; (b) treating the resulting solid with a complexant (e.g diisoamyl ether); (c) reacting the solid prod. from (b) with a chloro-alkane (esp. CCl4) and (d) sepg. the solid catalytic element. Cf. the catalyst of BE 780758, the present process obviates the use of the corrosive TiCl4 in stage (c).