regulation of molecular weight, molecular weight distribution and branching distribution in polyethylene, produced by supported catalysts bearing bis(imino)pyridyl fe(ii) and n,n-α-diimine ni(ii) complexes

For preparation of highly active supported catalyst with bis(imino)pyridyl fe(ii) complexes (fe1, fe2) and n,n-α-diimine complex of ni (ni3), silica modified with alumina (sio2 (al)) was used as a support. data on the possibility to regulate molecular weight (mw) and molecular weight distribution (mwd) of polyethylene (pe), produced over the supported catalyst fe1/sio2 (al)+tiba by variation of polymerization temperature and the addition of hydrogen and hexene-1, are obtained. the prepared pe samples were characterized by mw values varied from 80 to 350 kg/mol and various mmd (mw/mn =4.6-11.7). by grafting on sio2 (al) of two different iron bis(imino)pyridyl complexes, producing pe with diverse mw, bicomponent catalyst was prepared. this catalyst generates linear pe with broad and bimodal mwd (mw/mn =33). fixation on sio2 (al) of α-diimine ni(ii) pre-catalyst (ni3), yielding high molecular weight branched pe at the ethylene homopolymerization, and bis(imino)pyridyl fe(ii) complex (fe2) that forms lower molecular weight linear pe, affords formation of a new bi-component catalyst. the catalyst produces pe with broad mwd and high content of branches concentrated in high molecular weight pe fraction.