Phase diagram and thermochemical properties of organic eutectic in a monotectic system

Abstract

The phase diagram of a binary organic system involving diphenyl and succinonitrile shows the formation of a eutectic (0-968 mole fraction of succinonitrile) and a monotectic (0.074 mole fraction of succinonitrile) with a large miscibility gap in the system, the upper consolute temperature being 53-5°C above the monotectic horizontal. From the enthalpy of fusion of the pure components, the eutectic and the monotectic, determined by the DSC method, the enthalpy of mixing, Jackson's roughness parameter, interracial energy, size of the critical nudeus and excess thermodynamic functions were calculated.

Contribution of Crystal Lattice Energy on the Dissolution Behavior of Eutectic Solid Dispersions

“…In this way, the negative values of the fusion excess enthalpy of the eutectic mixture indicate the fine dispersion or the molecular clusters of ibuprofen crystals and caffeine crystals in the bulk of PEG and acetaminophen, respectively. ,,− The nondimensional fusion entropy (Δ S f °) for the pure components and respective eutectic mixtures is shown in Table . Fusion entropy was calculated using the enthalpy of fusion and fusion temperature. , Components from both the systems have Δ S f ° > 2 R , which indicates nondimensional entropy of fusion. , Fusion entropy data shows that the eutectic mixtures have higher Δ S f values than the minor crystalline component of the eutectic systems. This suggests that the eutectic mixture has a higher thermodynamic state compared to the minor component from IBU/PEG and APAP/CAFF systems.…”

“…Fusion entropy was calculated using the enthalpy of fusion and fusion temperature. 40,41 Components from both the systems have ΔS f °> 2R, which indicates nondimensional entropy of fusion. 23,24 Fusion entropy data shows that the eutectic mixtures have higher ΔS f values than the minor crystalline component of the eutectic systems.…”