Abstract: Preactivated unsupported catalyst compositions methods of using them are disclosed whereby the compositions have a concentration of preactivated catalyst of at least about 0.04 mmol of preactivated catalyst per liter of solution when using aliphatic or alicyclic hydrocarbon solvents, and a concentration of less than about 0.80 mmol/liter when using aromatic or halogen-substituted solvents. In the method, an unsupported catalyst precursor first is contacted with an activator, or co-catalyst, in a suitable reaction medium, and then the resulting mixture is contacted with additional solvent to form a preactivated unsupported olefin polymerization catalyst composition that can be fed to a gas phase polymerization reactor without plugging the catalyst injection nozzle.

Abstract: A fluidized bed olefin polymerization process is operated in the turbulent regime while utilizing greater than 17.5% liquid in the recycle fluid to remove the heat of reaction. The ratio of fluidized bed density to settled bed density may, contrary to prior art predelictions, be maintained at lower than 0.59.

Abstract: Preactivated unsupported catalyst compositions methods of using them are disclosed whereby the compositions have a concentration of preactivated catalyst of at least about 0.04 mmol of preactivated catalyst per liter of solution when using aliphatic or alicyclic hydrocarbon solvents, and a concentration of less than about 0.80 mmol/liter when using aromatic or halogen-substituted solvents. In the method, an unsupported catalyst precursor first is contacted with an activator, or co-catalyst, in a suitable reaction medium, and then the resulting mixture is contacted with additional solvent to form a preactivated unsupported olefin polymerization catalyst composition that can be fed to a gas phase polymerization reactor without plugging the catalyst injection nozzle.