Hydrogen response in liquid propylene polymerization: Towards a generalized model

Liquid propylene batch experiments in the absence of a gas phase have been carried out using a highly‐active MgCl2/TiCl4/phthalate/silane/AlR3 catalyst at varying temperatures (60‐80°C) and molar hydrogen‐monomer ratios of 0‐10 mmol/mol. With increasing hydrogen concentration the polymerization rate increases rapidly, reaching a constant value at concentrations above 1.4 mmol/mol; pseudo‐first‐order catalyst deactivation constant increases; molecular weight decreases; polydispersity decreases slightly; but average molecular weight and polydispersity increase with increasing temperature. Polymerization rate, deactivation constant, and average molecular weight can be modeled based on a consistent dormant site mechanism assuming an (averaged) quasi‐single‐site model.