Some Physicochemical Studies on Organic Eutectics and Molecular Complex: Urea – p -nitrophenol System

摘要: The phase diagram of urea–p-nitrophenol system, in the form a temperature-composition curve, shows formation 1: 1 molecular complex surrounded by two eutectics containing 0.216 and 0.777 mole fraction p-nitrophenol. Data on growth velocity (v), obtained measuring rate movement interface at different undercoolings (ΔT), suggest that they obey Hillig–Turnbull equation, i.e., v = u (ΔT)n, where n are constants depending nature materials involved. From heat fusion values, determined differential scanning calorimetry (DSC) method, mixing, entropy fusion, roughness parameter, interfacial energy, radius critical nucleus, excess thermodynamic functions were calculated. While x-ray diffraction data show not mechanical mixtures components under investigation, microstructural investigations give their characteristic features.