Oligomerization of isobutene has been carried out in the liquid phase at mild conditions using n-butane as a diluent. The reaction was studied at low temperatures (30-70 degrees C) and at pressures high enough to ensure that the reaction takes place in the liquid phase. A number of different resins and zeolites were evaluated as catalysts for the dimerization. The best performance was obtained with Amberlyst 15 whereas the zeolites (H-ZSM5, H-Mordenite, beta and Y) all showed very rapid deactivation. (c) 2004 Elsevier B.V. All rights reserved.