Thermal,physicochemical and microstructural studies of binary organic eutectic systems |
| |
Authors: | R S B Reddi V S A Kumar Satuluri U S Rai R N Rai |
| |
Institution: | (1) Department of Chemistry, Centre of Advanced Study, Faculty of Science, Banaras Hindu University, Varanasi, 221 005, India; |
| |
Abstract: | Solid–liquid phase equilibrium data of three binary organic systems, namely, 3-hydroxybenzaldehyde (HB)—4-bromo-2-nitroanilne
(BNA), benzoin (BN)—resorcinol (RC) and urea (U)—1,3-dinitrobenzene (DNB), were studied by the thaw–melt method. While the
former two systems show the formation of simple eutectic, the third system shows the formation of a monotectic and a eutectic
with a large immiscibility region where two immiscible liquid phases are in equilibrium with a liquid of single phase. Growth
kinetics of the pure components, the monotectic and the eutectics, studied by measuring the rate of movement (v) of solid–liquid interface in a thin U-tube at different undercoolings (ΔT) suggests the applicability of the Hillig–Turnbull’s equation: v = u (ΔT)
n
, where v and n are the constants depending on the nature of the materials involved. The thermal properties of materials such as heat of
mixing, entropy of fusion, roughness parameter, interfacial energy, and excess thermodynamic functions were computed from
the enthalpy of fusion values, determined by differential scanning calorimeter (Mettler DSC-4000) system. The role of solid–liquid
interfacial energy on morphologic change of monotectic growth has also been discussed. The microstructures of monotectic and
eutectics were taken which showed lamellar and federal features. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|