A new nickel complex for the oligomerization of ethylene

Article abstract of DOI:10.1021/om00077a004

We report the synthesis of (η³-C₈H₁₃)((C₆H ₅)₂PCH₂COO)Ni (1), which proved to be an excellent one-component model catalyst for the oligomerization of ethylene as practiced in Shell's higher olefin process (SHOP). In toluene solution this complex exists in two isomeric forms, the C₈H₁₃ ligand being 60% 4-enyl and 40% η₃-allyl. Under reaction conditions (75°C, 10-80 bar, ethylene in toluene) 1 catalyzed the highly selective oligomerization of ethylene to linear (99+%), α olefins (93-99%) at activities of 0.6 mol of ethylene/mol of Ni/s. The chain growth factor K ranges from 0.67 to 0.77 depending on reaction conditions. Kinetic activation parameters and reaction constants could be determined (E_a = 71 kJ mol^-1; S? = -49 J mol^-1 K^-1; k_insert/348K = 0.81 s^-1).