A semi-empirical study on Ziegler Natta catalyst::Concerning the interaction EtInd, ZrCl,/MAO/SiO2

M.L. FERREIRA; M. MARTA BRANDA; A. JUAN; D.E. DAMIANI

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

Elsevier

Año: 1997 vol. 122 p. 51 - 60

1381-1169

olymerization heterogeneous catalyst by modeling the adsorption of the ansa-metallocene ethylen-bisindenylzirconium dichloride (C,H,(C,H,@Cl, from now on EtInd,ZrCl,) on SiO, surfaces. The adsorption was considered to occur at two faces of SiO, (with geminal and isolated OH’s) and at two different temperatures for SiO, pretreatment (200 and 600°C). Taking into account that the interaction with Al compounds is considered as a way to improve the catalyst performance, specially with methylaluminoxane (MAO), a local model of aluminoxane (AlO) was added to Si-0 bond with the subsequent metallocene adsorption. The results show that A10 improves the zirconocene adsorption on SiO, modeled at 200°C while it inhibits that process at 600°C.