The co-adsorption of tetramethylpiperidine and TiCl4 on β-MgCl2 a theoretical study of a ziegler-natta pre-catalyst

FERREIRA, MARÍA L.; CASTELLANI, NORBERTO J.; DAMIANI, DANIEL E.; JUAN, ALFREDO

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

ELSEVIER SCIENCE BV

Año: 1997 vol. 122 p. 25 - 37

1381-1169

An extended Huckel method (ICONC), which includes core-core repulsion energy terms, was used to characterise the MgCl2/2,2,6,6-tetramethylpiperidine (TMPiP)/TiCl4 system by modelling the TMPiP and TiCl4 adsorption on the (100)-(101) and (110) faces of MgCl2. The results show how the amine modifies the chemical and electronic states of adsorbed TiCl4. The appearance of complexes at the surface, previously studied by infrared spectroscopy is supported by our calculation. The geometrical and structural factors governing the formation of precursors of active sites for propylene polymerisation were also studied.