GB860647A - Method for preparing titanium trichloride containing polymerization catalyst and polymerization process - Google Patents

Abstract

Alpha olefins, e.g. ethylene, propylene and isobutylene are polymerized by contact with a catalyst obtained by mixing titanium trichloride, prepared by heating vaporized titanium tetrachloride, if desired in the presence of hydrogen or a paraffinic hydrocarbon, or by exposing it to actinic light, and an organometallic compound in an inert organic diluent. The organometallic compound may be an aluminium alkyl, dialkyl or trialkyl, e.g. triethyl aluminium or diethyl aluminium chloride, and the catalyst may contain 0.05 to 1% by weight of a mixture of the aluminium and titanium compounds, with at least 0.5 mol. of aluminium compound per mol. of titanium trichloride, Preferably the polymerization is carried out at a pressure of 0 to 500 p.s.i.g. and at 50 DEG to 200 DEG F. Examples are given.ALSO:Titanium trichloride is prepared by heating, vaporized titanium tetrachloride, if desired in the presence of hydrogen or a paraffinic hydrocarbon, or by exposing it to actinic light. The titanium tetrachloride vapour may be contacted with an electric heating element at 800 DEG to 1200 DEG C., and the trichloride produced condensed as purple crystals in a non-polar liquid such as titanium tetrachloride or an organic liquid. Titanium trichloride may also be obtained by contacting titanium tetrachloride vapour and hydrogen with a heating element at at least 600 DEG C., by exposing the tetrachloride vapour to actinic light, or by reacting it with a C1 to C12 paraffinic hydrocarbon at at least 400 DEG C., preferably 650 DEG to 1000 DEG C. Polymerization catalysts are obtained by mixing the titanium trichloride obtained as above with an organometallic compound, e.g. an aluminium alkyl, dialkyl or trialkyl, e.g. triethyl aluminium or diethyl aluminium chloride, in an inert organic diluent. The composition should contain 0.05 to 1 % by weight of a mixture of the aluminium and titanium components, with at least 0.5 mol. of aluminium compound per mol. of titanium trichloride. Examples are given wherein titanium tetrachloride is contacted with heated filaments alone and in the presence of hydrogen, n-heptane and methane, and catalysts are prepared by mixing the titanium trichloride with triethyl aluminium in n-heptane.