A process for alkylating an aromatic compound containing no hydroxyl groups comprising reacting at least one non-hydroxyl containing aromatic compound with at least one olefinic oligomer in the presence of an acidic ionic liquid catalyst, wherein the olefinic oligomer has a carbon range of from about C.sub.12 to about C.sub.70 and is synthesized by oligomerizing at least one monoolefin monomer in the presence of an acidic ionic liquid catalyst.