Propene bulk polymerization kinetics: Role of prepolymerization and hydrogen

An experimental setup for the polymerization of liquid propylene was used to carry out main polymerizations with and without a prepolymerization step. Two types of prepolymerization are introduced: at a constant temperature and at rapidly increasing reactor temperatures. With the present catalyst system, at high polymerization temperatures, a prepolymerization step will increase polymerization rate. Hydrogen was used to control the molecular weight of the product. The polymerization reactor was used in combination with a gas chromatograph to determine the vapor‐liquid equilibrium (VLE) of the propylene‐hydrogen system. Measurements are compared to predictions of different equations of state. The Peng‐Robinson equation of state is best able to describe the VLE for this binary system. A temperature‐dependent interaction parameter was derived from the fits to the measured data.