Calculation of Kinetic Parameters and Active Sites Concentration for a New Multiple Site Model in Bulk Propylene Polymerization with the MgCl –Supported Ziegler–Natta Catalyst Using the Genetic Algorithm Method

摘要

A comprehensive triple-site-model was studied. This model was based on the new molecularndynamics outcomes obtained from the researchers on the different active sites that exist on thenheterogeneous Ziegler-Natta catalyst. The model was composed of high-isospecific site (IS), lowisospecificnsite (IS), and aspecific site (AS). A transformation occurred on the high isotactic sitenand a second isotactic site was generated, as the low-isospecific site. The model is able to predictnexperimental results of bulk propylene polymerization with great accuracy. Moreover, the kineticnparameters and constants for each individual site has an Arrhenius type behavior. These parametersnwere determined using genetic algorithm adaptation method. The concentration of each type ofnsites, the isotactic and atactic fraction were determined during the polymerization, per unit massnof catalyst. A very good agreement was found in between the model and reported experimentalnresults.