Some Physicochemical and Thermal Studies on Organic Analog of a Nonmetal-Nonmetal Monotectic Alloy;2-Cyanoacetamide–4-chloronitrobenzene System

摘要

The phase equilibrium data on organic analog of the nonmetal-nonmetal system, involving 2-cyanoacetamide (CA)―4-chloronitrobenzene (CNB), show the formation of a monotectic (0.10 mole fraction of CNB) and a eutectic (0.98 mole fraction of CNB) with a large miscibility gap starting from 0.10 mole fraction of CNB of monotectic (M) and ending at 0.92 mole fraction of CNB of monotectic horizontal (Mh);the upper consolute temperature Tc being 63?C above the monotectic horizontal at 118?C and eutectic temperature is at 85?C. The values of enthalpy of fusion of the pure components, the eutectic and the monotectic were determined by the differential scanning calorimetry (Mettler DSC-4000 system). Using these data, the size of the critical radius, interfacial energy, excess thermodynamic functions, entropy of fusion, and enthalpy of mixing were calcu-lated. The solid-liquid interfacial energy data confirm the applicability of the Cahn wetting condition. While growth data obey the Hillig-Turnbull equation, the microstructural investigations give typical characteristic features of the eutectic and the monotectic of the system.