Volumetric and Viscous Properties at Several Temperatures for Binary Mixtures of N-Methylpiperazine with Methylcyclohexane or n-Heptane

The data of density and viscosity for binary mixtures of N-methylpiperazine (NMP) with methylcyclohexane (MCH) or n-heptane have been measured from T = 298.15 K to T = 313.15 K at atmospheric pressure. Excess volume, V-m(E), for the binary mixtures are then calculated. Positive values of V-m(E) are observed over the entire composition range, and the maximum value is 0.622 cm(3).mol(-1) at 313.15 K. The excess results are discussed in terms of the changes of molecular interactions in the mixtures, and the data of V-m(E) are fitted against the composition with the Redlich-Kister type equation. The viscosities have also been correlated with several semiempirical equations. These physical property data and calculations provide valuable information on the development and application of piperazine derivatives.