Dimerisation of isoamylenes coming from a pentane catalytic dehydrogenation process is an option to transform these branched olefins into unsaturated compounds of ten carbons (diisoamylenes). Dimers derivatives have a wide range of industrial applications. The present research sets the basis for the development of a feasible process of branched pentene dimerisation using fluorinated alumina as catalyst. Experimental tests were carried out in a packed bed reactor. 2-methyl-2-butene was used as model reactant. The effluent composition was followed by gas chromatography and mass spectroscopy. Solid characterization was done by means of surface area, total acidity, elemental and thermogravimetric analysis.