  Molecular Dynamics simulations are performed on two sodium chloride solutions
in TIP4P water with concentrations c=1.36 mol/kg and c=2.10 mol/kg upon
supercooling. The isotherms and isochoresplanes are calculated. The temperature
of maximum density line and the limit of mechanical stability line are obtained
from the analysis of the thermodynamic planes. The comparison of the results
shows that for densities well above the limit of mechanical stability, the
isotherms and isochores of the sodium chloride aqueous solution shift to lower
pressures upon increasing concentration while the limit of mechanical stability
is very similar to that of bulk waterfor both concentrations. We also find that
the temperature of maximum density line shifts to lower pressures and
temperatures upon increasing concentration. Indications of the presence ofa
liquid-liquid coexistence are found for both concentrations.
