| 摘要 |
A halogen-containing alumina catalyst for the polymerization of olefins to liquid polymers containing a major proportion of polymers having a molecular weight higher than the trimers, said catalyst selectively polymerizing isobutene from a mixture of butenes to produce liquid polyisobutene having a molecular weight higher than about 280; said catalyst containing from about 2 to about 20 wt. % chlorine, bromine or a mixture thereof, and being prepared from an alumina having a purity of at least 99% and a surface area greater than about 150 m2/g with at least 10% of the pores having a diameter higher than about 200 ANGSTROM ; said preparation being effected by contacting the alumina with a dry gaseous stream comprising a halogenation agent consisting essentially of volatile chlorinated and/or brominated saturated oliphatic organic compound having a vapor pressure of at least 100 mm of Hg at a temperature of 200 DEG -230 DEG C. and having a low hydrogen content, together with a non-reducing gaseous carrier at a temperature from about 230 DEG to about 300 DEG C. during a period of time t in hours such that the ratio t/R, wherein R is the mole ratio of gaseous carrier to halogenation agent, ranges between about 0.35 and about 20.
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