Polymerization process

Polymers of one or more diene hydrocarbons are made by polymerizing a monomer, e.g. isoprene, in the presence of catalyst obtained by reacting in an inert liquid diluent a metal, hydride, or organometallic compound of a metal of Group I to III of the Mendelaeeff Periodic Table with TiCl4, in the presence of a finely-divided inert solid supporting medium that is insoluble in water, to reduce the TiCl4 to a lower valency state, and mixing the reaction product together with the support with a metal, hydride, or organometallic compound of a metal of Group I to III of the Periodic Table. The reduction of the TiCl4 is preferably effected at an elevated temperature, e.g. 135 DEG to 175 DEG C. to give violet TiCl3, and below 100 DEG C. to give brown TiCl3. The supporting medium has generally a surface area of 3 to 50 sq.m./gm. The supporting medium may be TiO2, SiO2, alumina, magnesia, zirconia, kaolin talc, calcium silicate, or barium, strontium, and calcium sulphates. The polymerization is effected in the presence of conventional hydrocarbons. An ether such as diisopropyl ether, may be present in the polymerizable mix.ALSO:Titanium trichloride in the violet (alpha) form or beta-form (brown) is made by reducing TiCl4 with an organo-metallic compound, preferably aluminium in the presence of an inert, finely divided, solid supporting medium for the TiCl3. When the organo-aluminium compound is Al(alkyl)3 the molar ratio to TiCl4 should be about 0.42 : 1, and when the aluminium compound is Al(alkyl)2 halide, the molar ratio should be about 0.6 to 1-1 : 1. The reaction is effected in a hydrocarbon solvent or diluent. The reduction, or the reduced product may be heat-treated at 135 DEG to 175 DEG C. to give violet TiCl3, or below 100 DEG C. to give brown TiCl3. In Example I, supported TiCl3 is made by dispersing dry TiO2 in pure decane, adding TiCl4 and raising the temperature to 150 DEG C., adding Al(C2H5)3 portionwise, raising the temperature to 155 DEG to 165 DEG C., and after 3 hours, recovering and vacuum drying the TiCl3 supported on TiO2. The reduction is effected in an inert atmosphere.