(477g) Nucleation Behavior of Ethyl Vanillin: The Partial Dependence of Kinetic Parameters on Interfacial Energy

The experimental metastable zone width (MSZWs) of ethyl vanillin (EVA) in ethanol, n-propanol and n-butanol were measured by the polythermal method to describe the nucleation behavior in its unseeded cooling crystallization. In accordance with the classical nucleation theory (CNT), the dependences of MSZWs on saturation temperature T₀ and cooling rate R were mainly discussed via Nývlt's semiempirical model and modified Sangwal's theory, respectively. Meanwhile, the pre-exponential factor A, crystal-liquid interfacial energy γ and the corresponding critical parameters r_crit (critical nucleus size), â–³G_crit (critical Gibbs free energy) can be obtained. It is interesting to find that γ increases linearly with decreasing T₀ and increasing R, while the value changes of A do not have regularity against thermodynamics and kinetics. As the result, the increase or decrease of nucleation rate J mainly depends on the increments of γ more than the slight variation of A. Furthermore, it suggests that the thermodynamic dependence of γ is greater for the system with higher supersaturated concentration of solute.