Brillouin light scattering measurements under pressure on Methanol:Water solutions provided the first hints suggesting a change of behavior at a cross-over pressure of ~4kbar. At ambient pressure the system behaves as a hydrogen-bonded liquid network at low MetOH concentrations and presents well-defined structural correlations at high alcohol concentrations that correspond to an inhomogeneously mixed system. At a pressure of ~4 kbar, the system becomes a simpler molecular liquid, possibly chemically homogeneous. Here we propose to study the microscopic correlate by means of:1)A quasielastic neutron scattering experiment on IN5 in order to study the microscopic dynamics of the system under high pressure conditions. We plan to study the effect of the applied pressure on the dynamics of the hydrogen bond network and the methyl group by using partially deuterated samples across the pressure of ~4kbar.2)An inelastic neutron scattering experiment on BRISP, the thermal neutron Brillouin scattering spectrometer, in order to study the collective excitations of deuterated methanol/water mixtures at P = 5 kbar.