Liquid-liquid equilibrium (LLE) data were measured for the binary system propylene carbonate/decane (288.15 to 403.15 K) as well as for the ternary systems propylene Carbonate/decane + linear aldehyde (C4, C8, C10, C12, C13) and DMF/decane + linear aldehyde (C4, C8, C10, C13) at 298.15 K using the analytic method. The reliability of the ternary LLE data is ascertained by employing Othmer-Tobias plots. Concerning the aldehyde distribution coefficients in the ternary systems, a distinctive dependency on the chain length of the aldehyde was observed. The LLE data were modeled with the Perturbed Chain Polar Statistical Associating Fluid Theory (PCP-SAFT) equation of state using a heterosegmented approach for describing the aldehyde molecules