The invention discloses a preparation method of
polyethylene wax, a three-level pore channel supported catalyst TiCl4 / MgCl2. MSiO2 with a micropore-mesopore-
macropore hierarchical structure is created for the first time, a high-density
active site supporting space is combined with a hexagonal mesopore through network formed by self-
assembly of a template agent, so that the substance
diffusion rate is increased by 3-5 times, the
diffusion gradient in particles is eliminated, and the stability of the particles is improved. The
ethylene and
hydrogen can be quickly diffused to the
active center, the escape of
wax molecules is accelerated, the pore channel blockage can be effectively prevented, and the molecular
weight distribution PDI of the
polyethylene wax is less than 1.2 and can reach 1.05. MgCl2
crystal lattices are embedded into a SiO2 skeleton to form a cage-shaped structure, so that the
dispersity of the
active center of Ti is gt; the
catalytic effect is improved by 40-50%, and the single service life is prolonged by more than 300%. Borate [Ph3C] [B (C6F5) 4] is innovatively adopted to replace traditional
aluminum alkyl to serve as a cocatalyst, the yield of
ethylene oligomerization by-products (C4-C8) is smaller than 0.8 wt%, and the selectivity of main products is larger than 99%; functional
silane tert-butyl-cyclohexyldimethoxysilane is adopted as an
electron donor, so that the
hydrogen chain transfer efficiency is improved by 20-30%.