Industrial processes :

Usually, there are three representative way to produce polypropylene.

Hydrocarbon slurry / suspension: Uses a liquid inert hydrocarbon diluent in the reactor to facilitate transfer of propylene to the catalyst, the removal of heat from the system, the deactivation of the catalyst as well as dissolving the atactic polymer. The variety of grades that can be produced was very limited. (The technology has fallen into disuse).

Bulk (or bulk slurry): liquid propylene can be used instead of liquid inert hydrocarbon diluent. The polymer does not dissolve into a diluent, but rather rides on the liquid propylene. The formed polymer is withdrawn and any unreacted monomer is flashed off.

Gas phase : Uses gaseous propylene in contact with the solid catalyst, can result in a fluidized-bed medium.