In an embodiment, a method is disclosed to increase the activity of an ionic liquid catalyst comprising contacting an ionic liquid catalyst with oxygen. In another embodiment, a method is disclosed comprising introducing into a reaction zone a monomer feed and an ionic liquid catalyst and controlling the amount of oxygen present in the reaction zone to maintain a conversion reaction of the monomer. In another embodiment, a polyalphaolefin oligomerization system is disclosed comprising a reactor configured to receive and mix monomer, ionic liquid catalyst, and oxygen; and a controller coupled to an oxygen source and configured to control the amount of oxygen present in a catalyzed reaction zone to maintain a conversion reaction of the monomer.