Metal complexes in catalytic conversions of olefins. 4. Heterogenization of nickel complexes on chemically modified silochrome surface; activity and selectivity in ethylene dimerization
When activated by Et2AlCl phosphine-containing homogeneous nickel complexes and their heterogenized analogs (HMC) formed on silochrome S-120 modified by NH2 and N(PPh2)2 groups differ significantly in their effectiveness in ethylene dimerization. The catalytic activity of Ni-HMC-Et2AlCl depends on how the HMC was formed. Ni-HMC-I obtained by ligand exchange on chemically modified silochrome is ∼5–15 times more effective than Ni-HMC-II synthesized from the gas phase. The selectivity in formation of α-olefins (σC4 + σC6) is ∼4–5 times higher in the presence of Ni-HMC than for its homogeneous analogs.