The direct conversion of n-pentane to isopentene by dehydrogenation and isomerization in a single step was studied on Pt supported over SAPO-11, ferrierite (FER) and HZSM5 molecular sieves. The Pt/SAPO-11 presented the best selectivity to mono-branched pentenes. The characterization of acidic sites with isomers of propylamine revealed a better capacity for SAPO-11 to diffuse mono-branched amines and that is considered a consequence of its pore geometry, which could explain the obtained selectivity.