OPTIMIZATION OF HEXENE-1 YIELD IN THE COURSE OF OLIGOMERIZATION OF ETHYLENE ON ZIRCONIUM-CONTAINING COMPLEX CATALYSTS

Analysis of the kinetic model of ethylene oligomerization on zirconium-containing complex catalysts was carried out. The dependence of the molar fraction of individual higher alpha-olefins N(i) on the number of units in a molecule i of the product is described by the exponential function N(i) = ab(i). The dependence of the mass fraction of hexene-1 (trimer W3) in the products of ethylene oligomerization on the probability of chain growth b = k(p)/(k(p) + k(n)M) was found to be extreme, and (W3)max cannot exceed 27 mass %. The dependences W(i) on b for any i > 3 are similar. The mass fraction of butene-1 (i = 2) increases monotonously from 0 to 100 mass %, as b decreases from 1 to 0. This means that the selective dimerization of ethylene to butene-1 can be performed. At the same time hexene-1 and other alpha-olefins cannot be obtained selectively by the methods of catalytic trimerization and oligomerization of ethylene, respectively. Experimental data are present which confirm the theoretical estimations.