Study of the effect of hydrogen in propylene polymerization with the MgCl2-supported ziegler-natta catalyst—part 1. Kinetics of polymerization

Hydrogen response in liquid propylene polymerization: Towards a generalized model

“…The plateau effect at high hydrogen concentrations has been confirmed by several authors 2, 4, 9, 14. Guastalla and Giannini14 proposed the presence of adsorption phenomena of hydrogen on the surface of the solid catalyst, with a saturation at high concentrations.…”

“…For this catalyst, about 1/9 (11%) of the potentially active sites are really active if one assumes that all potentially active sites are active at the hydrogen plateau. This is in agreement with the kinetic data discussed by Rishina and coworkers 9. This part is temperature independent, at least within the temperature and concentration ranges measured in this research.…”

“…Only a very few experimental studies have been carried out so far to investigate the effect of hydrogen during liquid propylene polymerization; most studies were performed in either a gaseous monomer or slurry,1–15 but gas phase and slurry phase results cannot easily be compared and heat and sorption effects and mass transfer limitations may play a role 16…”

Modeling and simulation of propylene polymerization in nonideal loop reactors

“…Ž . Parson and Al-Turki 1989 , Rishina et al 1994 , and Soares Ž . and Hamielec 1996a proposed an increase in the number of active sites when hydrogen is present in the reaction media.…”

Effect of Hydrogen and External Donor on the Microstructure of Polypropylene Made with a 4th Generation Ziegler–Natta Catalyst

“…In addition to its role as chain transfer agent, hydrogen increases propylene polymerization rate with TiCl 4 /MgCl 2 catalysts, but it generally reduces the polymerization rate of ethylene 3–7. Guastalla and Giannini8 showed that the enhancement in propylene polymerization rate caused by hydrogen was limited to a maximum hydrogen partial pressure of about 0.6 kg · cm −2 for the system they investigated.…”