| abstract |
A process for the polymerization of a liquid alpha-olefin per se or in combination with one or more other alpha-olefins, which are themselves liquids or are dissolved therein, each alpha-olefin having 2 to 12 carbon atoms, comprising the following steps, step (a) being carried out in the liquid phase and step (b) being carried out in the gas phase: (a) admixing a catalyst comprising (i) a catalyst precursor, which includes magnesium, titanium, chlorine, and an electron donor; (ii) a hydrocarbylaluminum cocatalyst; (iii) a selectivity control agent, said selectivity control agent being different from the electron donor; and (iv) hydrogen with the alpha-olefin(s), the ratio, by weight, of alpha-olefin(s) to catalyst precursor being at least about 6,000:1, in a liquid phase reactor for a residence time in the range of about 10 seconds to about 400 seconds at a temperature in the range of about 20 DEG C to about 100 DEG C whereby the alpha-olefin(s) are partially polymerized; and (b) introducing the mixture from step (a) into at least one gas phase reactor at a temperature in the range of about 40 DEG C to about 150 DEG C in such a manner that the unpolymerized alpha-olefin is substantially polymerized. |