A METHOD FOR THE PREDICTION OF METALLOCENE-TYPE CATALYST ACTIVITY IN OLEFIN (CO)POLYMERISATION REACTIONS

The use of ultraviolet/visible spectroscopy (UV-Vis) for the predictio n of metallocene catalyst potential for the polymerisation of olefins is described. Upon addition of methylaluminoxane (MAO) to rac-[C2H4(1- indenyl)(2)ZrCl2] ([Al]/[Zr] = 200) the ligand-to-metal charge transfe r band shows a hypsochromic shift while a bathochromic shift is observ ed when more MAO is added ([Al]/[Zr] = 2000). These shifts can be expl ained by assuming that methylation of the zirconocene by MAO occurs in the case of [Al]/[Zr] = 200 while a cationic complex, the active cata lytic system, is formed upon addition of more MAO, e.g., [Al]/[Zr] = 2 000.