GB800447A - Propylene polymerization - Google Patents

Abstract

A catalyst suitable for polymerizing propylene is made by mixing, in an inert diluent at a temperature of 25 DEG to 50 DEG C. for 1/4 to 1 hour, compounds of the formula AlR1R11R111, AlR1 R11X and TiCl4, where R1, R11 and R111 are C2-C4 alkyl groups and X is halogen and the molar ratio of aluminium to titanium is in the range 1 : 1 to 12 : 1 and the molar ratio of the aluminium trialkyl compound to the aluminium dialkyl compound is in the range of 1 : 19 to 19 : 1. Specified aluminium trialkyls are aluminium triethyl, tripropyl, tributyl, diethyl propyl, and ethyl dibutyl. The aluminium dialkyl halide may be aluminium diethyl chloride, bromide, or iodide, aluminium dibutyl chloride, or aluminium ethyl butyl chloride. Diluents mentioned are pentane, hexane, heptane, octane, nonane and decane.ALSO:Propylene is polymerized at a pressure in the range of 100 to 2000 lbs./sq. inch in the presence of a catalyst obtained by mixing compounds of the formula AlR1R11R111, AlR1R11X an TiCl4, where R1, R11 and R111 are C2-C4 alkyl groups and X is halogen and the molar ratio of the aluminium trialkyl compound to the aluminium dialkyl halide compound is in the range of 1:19 to 19:1 and the molar ratio of aluminium to titanium is in the range 1:1 to 12:1. The polymerization is preferably effected in an inert liquid diluent which is generally the same diluent as is employed in the preparation of the catalyst. Specified aluminium trialkyls are aluminium triethyl, tripropyl, tributyl, diethyl propyl, and ethyl dibutyl. The aluminium dialkyl halide may be aluminium diethyl chloride, bromide, or iodide, aluminium dibutyl chloride, or aluminium ethyl butyl chloride. Diluents mentioned are pentane, hexane, heptane, octane, nonane, and decane. The catalyst is generally made by mixing the three compounds in a diluent at a temperature of 25 DEG to 50 DEG C. for 0.25 to 1 hour. After the polymerization is complete the catalyst is deactivated by treating with an alcohol such as methyl, ethyl, isopropyl, or n-butyl. The polypropylene has an intrinsic viscosity within the range of 0.2 to 6.0 and may be prepared in two forms, i.e. amorphous or crystalline. The formation of the amorphous polymer is promoted by (1) employing high molar ratios of aluminium trialkyl to dialkyl aluminium halide, (2) employing relatively low molar ratios of aluminium to titanium and (3) low polymerization temperatures. The formation of the crystalline polymer is promoted by low molar ratios of (1), high molar ratios of (2), and a high polymerization temperature. The polymerization may be effected in a reaction vessel constructed of alloy steel essentially free of the elements nickel, lead, platinum, palladium, or cobalt. The polymer may be used as a lubricating oil additive, in coating compositions, and in the manufacture of extruded sheets, tubes, and moulded articles.