PRODUCTION OF MONOOLEFIN OLIGOMER

A monoolefin oligomerization process which gives high yields of dimer and trimer at high monoolefin conversions in a single stage reaction is described. The process involves contacting a C6-20 oligomerizable olefin with a catalyst comprising boron trifluoride and from 0.05 to 2.5 mol%, based on the total quantity of monoolefin being used, of an alcohol catalyst promoter which is added portionwise during the oligomerization. The oligomerization is performed at a temperature of 45- 90.degree.C and under a pressurized atmosphere of boron trifluoride until the monoolefin conversion is at least 90% and the combined total of dimer and trimer in the liquid reaction mixture is at least 70% by weight.