| 摘要 |
A process for polymerizing terminal vinyl olefins to obtain normally solid polymers comprises contacting such olefins in liquid phase with a catalyst system comprising (a) a minor amount of an oxide of Mo such that the valency of Mo is less than 6 supported on Al2O3 having a surface area of 1-1500 m2/gm. which has been contacted prior to use with a hydrogen halide in the vapour phase at a temperature in the range of about 150-500 DEG C. and (b) one or more of Na, Li or Ca metal. The olefin is preferably ethylene or propylene or mixtures thereof. The polymerization may be of the "solution" or "suspension" type and various inert hydrocarbon media are specified. Other olefins specified are 1-butene, 1-pentene, 1-heptene, 1-octene, 1-dodecene, 1-tetradecene, 1-hexadecene, 3-methylbutene, 4-methylpentene, 5-methylhexene, styrene, a -methylstyrene, butadiene, isoprene, chloroprene, piperylene, cyclopentadiene, tetrafluoroethylene, perfluorovinyl chloride, norbovinylene, 4-vinyl-cyclohexene and vinyl cyclohexane. Examples are given.ALSO:A catalyst is made by contacting an oxide of molybdenum supported on Al2O3 having a surface area of 1-1500 m2/gm with a hydrogen halide in vapour phase at a temperature of 150-500 DEG C., the oxide of Mo being in a valency state of less than 6 or subsequently converted thereto. g -and e -type aluminas are referred to as supports. Additionally the catalyst may contain one or more of the following metals Na, Li and Ca. The alumina support may be associated with SiO2, ZrO2, TiO2 or CoO. Hydrohalogenation may be effected with HCl, HBr, Hi or HF or substances capable of yielding these on contact with the catalyst e.g. fluorophosphoric, fluorosulphonic and chlorosulphonic acids. Examples are given in which olefins are polymerized in the presence of such compositions. |
