Novel Ni-SIRAL Catalyst for Heterogeneous Ethylene Oligomerization

We describe a novel route for producing alkenes and cycloalkanes via the oligomerization of ethylene with a novel Ni-SIRAL catalyst. We report the production of liquid products (ambient conditions) at 50, 100, and 200 °C with subcritical and supercritical ethylene using Ni-SIRAL catalysts with nickel loadings varying from 0.4 to 6.9 wt %, operating at both single- and dual-reactor configurations. The highest liquid yield, 43 wt %, with a single reactor, was obtained at supercritical conditions (65 bar), at 200 °C, with a nickel loading of 2.8%. Under supercritical conditions, at 200 °C, the liquid yield increased from 43 to 80 wt % after the addition of a second oligomerization reactor using the Ni-SIRAL catalyst with 2.8 wt % nickel. The ethylene oligomerization under subcritical conditions (40 bar) led to a much lower yield for liquid products than the yield obtained at supercritical conditions at both reactor configurations (single and dual). The dual-reactor configuration proved to be the better configuration for the production of cycloalkanes, with a yield of 7 wt % at subcritical conditions and 10 wt % at supercritical conditions. We proposed a reaction pathway consistent with the experimental data.