Nuclear particle production from peripheral to central events is presented. N/Z gradient between projectile and target is studied using the fact that two reactions have the same projectile+target N/Z and so the same neutron to proton ratio for the combined system and the impact parameter size dependent geometrical overlap region. Data in the forward part of the centre of mass indicates that N/Z equilibration is achieved for impact parameters below 6 fm and a comparison with transport model SMF calculations is done. SMF results agree with the data in average and by using the fragment multiplicity difference between 136Xe+112Sn and 124Xe+124Sn systems it seems possible to characterize the density dependence of the symmetry energy.