STUDIES OF PROPYLENE OLIGOMERIZATION OVERNI(II) SUPPORTED ON AMORPHOUS ALUMINASILICATE CATALYST .3.INTERACTION OF NICKEL IONS WITH PROPYLENE MOLECULES

To ascertain the cause of the formation of induction period in propyle ne oligomerization and the nature of active centers on nickel ions sup ported amorphous aluminasilicate catalyst (Ni-SA), the interaction of nickel ions with propylene molecules has been investigated with ESR, X PS measurements, in a closed recirculation apparatus. It was found tha t the induction period is shorted by increasing the pre-evacuation tem perature and reaction temperature. ESR and XPS results show that Ni(II ) has been reduced Into Ni(I) by propylene, then Ni(I) ions form unsat urated complexes with propylene. It is suggested that the unsaturated complexes are active intermediates of propylene oligomerization. It is their formation that results in the elimination of the induction peri od. At the same time, the dimer or trimer coordinates to Ni(I) ions an d forms the active intermediates of trimerization or tetramerization. The catalytically active centers are Ni(I) ions on Ni-SA catalyst.