Solid–Liquid Phase Equilibrium of N,N′-Piperazinebis(neopentylglycol)phosphoramidate in Selected Solvents from T = (293.15 to 333.15) K

A phosphorus flame retardant named N,N′-piperazinebis(neopentylglycol)phosphoramidate (PBNGP) was synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy, mass spectra, and nuclear magnetic resonance. Its thermal properties were evaluated via thermogravimetric analysis and differential scanning calorimetry. The solubilities of PBNGP in selected solvents at T = (293.15 to 333.15) K and atmospheric pressure were measured via a static-analytic method. The experimental data were correlated with Scatchard–Hildebrand, Buchowski-Ksiazczak, Wilson, nonrandom two liquid, and universal quasichemical equations. The calculated results showed that all of these models can reproduce the experimental data well, and the Wilson model gives the best correlation, with an overall relative standard deviation of 0.70%. The solubility parameter of PBNGP was calculated using the Scatchard–Hildebrand methodology.