Heterocene Catalysts and Reaction Temperature Gradient in Dec-1-ene Oligomerization for the Production of Low Viscosity PAO Base Stocks
Ilya E. Nifant’ev, Alexander A. Vinogradov, Alexey A. Vinogradov, Vladimir V. Bagrov, Artem V. Kiselev, Mikhail E. Minyaev, Tatyana I. Samurganova, Pavel V. Ivchenko
Abstract
Hydrogenated oligomers of higher α-olefins (primarily, dec-1-ene) with uniform structure represent high-quality poly-α-olefin oil (PAO) base stocks. High yields of lightweight dec-1-ene oligomers ( DP n = 3–4) can be achieved by using 5,10-dihydroindeno[1,2- b ]indole-based zirconium ansa -complexes, “heterocenes”. Unusual catalytic behavior of heterocenes served as a starting point for the present study, during which new, more synthetically available and active heterocene precatalysts were synthesized, and a novel oligomerization method, based on a reaction temperature gradient, was developed. A gradual decrease of the oligomerization temperature as dec-1-ene was consumed resulted in decreased dimer formation (down to 10%) and increased oligomer yields (up to 84%). After hydrogenation, low- and medium-viscosity PAO base oils with uniform structure and high viscosity indexes were obtained.