Solidification behaviour of binary organic eutectics and monotectics; 1,2,4,5-tetrachlorobenzene-m-aminophenol system

The phase-diagram of the 1,2,4,5-tetrachlorobenzene-m-aminophenol system st udied by the thaw-melt method shows the formation of a eutectic at 120.0 de grees C (0.946 mole fraction of nt-aminophenol) and a monotectic at 136.0 d egrees C (0.094 mole fraction of m-aminophenol) with a consolute temperatur e at 177.0 degrees C. The growth kinetic studies at different undercoolings (Delta T) by the capillary method give straight lines for the plots betwee n log v and log Delta T where v is the rate of movement of solid-liquid int erface. From the enthalpy of fusion of the pure components, the eutectic an d the monotectic determined by the DSC method, different thermodynamic para meters such as enthalpy of mixing, excess thermodynamic functions and entro py of fusion were calculated. While the microstructure of the pure componen ts give their faceted growth, the eutectic and the monotectic show their ch aracteristic features. (C) 1999 Elsevier Science B.V. All rights reserved.