The pH influence of the impregnation solution and the effect of W and Ni content in texture, acidity and catalytic activity during thiophene hydrodesulfurization, have been studied for the catalytic N-W/C system, using as support, activated carbon obtained from Eucalyptus globulus chips, at a laboratory level. These catalytic systems presented high activity and selectivity to cis and trans butene, butadiene and 1-butene, and limited hydrogenating and cracking capacity due to their low acidity. The synergetic behavior of the bimetallic system in the HDS activity, under atmospheric pressure, and the increase in the density and strength of acid sites are probably produced by the formation of a non crystalline phase Ni-W(S) interacting with the oxygenated surface functional groups of the activated carbon.