INFLUENCE OF THE DONOR NATURE ON THE CATALYTIC POLYMERIZATION OF 1,3-BUTADIENE IN THE PRESENCE OF ZIEGLER-TYPE TITANIUM SYSTEM.

The polymerization of 1,3-butadiene under the influence of the catalyst system TiI//2-Cl//2-Al (iso-C//4H//9)//3 has been investigated in mixtures of aromatic solvents with hexane and in toluene with small additions of n-donors. The significant change in the ionization potential of the aromatic solvent observed when changing from benzene to mesitylene has no noticeable effect on the rate of the process and the properties of the polymer. Small additions of n-donors significantly retard the polymerization or inhibit it completely. A mechanism is proposed which attributes the influence of differnet donor types to the formation of a dative bond in the case of pi -donors and to its absence in the interaction of active centers with n-donors.