| 摘要 |
a -Olefins are polymerized in presence of a catalyst obtained by refluxing a titanium tetrahalide in an inert solvent with zinc dimethyl or a zinc methyl halide, removing subsequently substantially all of the zinc compounds and converting the "prereduced" titanium compound to an active catalytic species. The removal of zinc compounds may be effected by filtration and/or distillation; irradiation or heating may be used to activate the catalyst. Cyclohexane is the preferred solvent, but others are mentioned. In the example, ethylene is polymerized using a catalyst prepared from TiCl4 and ZnMe2 and subsequently subjected to ultra-violet radiation. The "prereduced" compounds have the formula TiXmMen (m+n=4) while in the reduced compounds (m+n) is less than 4. Belgian Specifications 533,362, 534,888, 538,782, 540,459, 543,259 and U.S.A. Specification 2,862,917 are referred to.ALSO:Compounds of formula TiXm(CH3)n wherein (m+n) is less than 4 are obtained by irradiating or heating compounds of said formula wherein m+n=4, the latter compounds having been obtained by refluxing TiX4 (X=halogen) in an inert solvent with Zn(CH3)2 or CH3ZnX and removing the zinc compounds by filtration and/or distillation. |
