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. © 2006 American Institute of Chemical Engineers AIChE J,2006