Thermophysical properties of partially miscible binary systems {N-methylpiperidine - H2O} and {H2O- 2-methylpiperidine} were studied. Limits of mutual solubility are determined using both a calorimetric technique and an equilibrium cell. Densities of the aqueous solutions are determined at temperatures range from 298.15 K to 327.85 K, for methylpiperidines compositions corresponding to water-amine miscibility. Excess molar volumes are calculated using the experimental density data and fitted to a Redlich–Kister type equation. Specific heat capacities are determined at 308.15 K in the one phase region using a calorimetric technique. First experiments have been performed to determine optically the phase diagram for ternary mixtures {methylpiperidine - H2O – CO2}. Only the results concerning N-methylpiperidine are presented in this paper.