Olefin oligomerization process

A process for making an .alpha.-olefin oligomer comprising reacting an .alpha.-olefin monomer containing from about 6 to 20 carbon atoms in the presence of a catalyst comprising, at least about 0.002 moles of boron trifluoride per mole of said monomer, from about 0.001 to 0.04 moles of a protic promoter per mole of said monomer, and a polyether in a mole ratio of promoter to polyether of from about 0.5 to 10, so as to form said oligomer product.