Excess molar volumes and excess isentropic compressibilities of liquid mixtures formed by tetrahydropyran, piperidine and cyclic ketones at temperature from 293.15 to 308.15Â K.

The densities, ρ, ρ123 and speeds of sound, u, u123 of binary Tetrahydropyran (1) + Piperidine (2) and ternary Tetrahydropyran (1) + Piperidine (2) + Cyclohexanone or Cycloheptanone (3) mixtures have been measured over the whole range of mole fraction at 293.15, 298.15, 303.15, 308.15 K and atmospheric pressure. The observed data have been utilized to determine excess molar volumes, (VE)12, V123E and excess isentropic compressibilities, (κSE)12, (κSE)123 for the binary and ternary liquid mixtures respectively. The (VE)12, V123E and (κSE)12, (κSE)123 data have been fitted to Redlich-Kister equation to determine binary as well as ternary adjustable parameters along with standard deviations. The Moelywn-Huggins concept of interaction between the surfaces of the binary mixture constituents has been extended (Graph theory) to evaluate excess molar volumes and excess isentropic compressibilities of ternary mixtures using the concept of connectivity parameter of third degree of molecules, 3ξ (which deals with the topology of the constituents in pure and mixed state) to obtain an expression that describe well the measured data.