6533b85bfe1ef96bd12bb772

RESEARCH PRODUCT

Wpływ tlenku glinu jako nośnika katalizatora tytanowo-glinowego, na aktywność tego katalizatora w polimeryzacji etylenu

subject

description

The chemical and physical character of A120 3 surface was modified with halogen-containing compounds and by subsequent calcination at 773–1373 K. An increase of the acidic character of the carrier (modification with HC1) has an activating effect on the catalytic properties of the surface complex of Ti in ethylene polymerization. On the other side, the interaction of basic centres (modification with NaCl or NaF), by inductive effects on the titanium active centres, reduces their ability to coordinate olefin; this results in a reduction of the catalytic activity. It was found that both a modification with HC1 and heating of the carrier at temperatures above 773 К results in a change of the physical structure of carrier surface. The specific surface and volume of pores decreases and their diameter increases, what contributes to an increase in the contribution of A120 3 surface in the formation of active surface-complexes of titanium. It was also established that the factor deciding about Ah03 activity, used as a carrier of the Ti-catalyst of ethylene polymerization, is neither the chemical character of A120 3 surface (including the presence of OH groups)nor the degree of its development, but an appropriate character of the porous structure with wide and shallow pores accessible both for the catalyst components and for the growing polymer molecules.