Exploring the solubility and solvation energetics of L-phenylalanine across diverse aqueous organic solutions at five equidistant temperatures (288.15 K to 308.15 K)

Abstract

This research elucidates comprehensive insights into the dissolution nature and solvation energetics of L-phenylalanine across distinct solvent environments. Specifically, the investigation encompasses saturated solubility measurements and the subsequent derivation of overall transfer free energies (ΔGt0(i)) and entropies (ΔSt0(i)) at 298.15 K, of L-phenylalanine from an aqueous medium to aqueous solutions comprising protic ethylene glycol (EG), dipolar aprotic N,N-dimethylformamide (DMF), acetonitrile (ACN), and dimethyl sulfoxide (DMSO). In this study the 'gravimetric method' was used to find the saturated solubilities of L-phenylalanine at five equidistant temperatures (288.15 K to 308.15 K). These experimental solubility measurements serve as the foundational dataset for the subsequent determination of transfer energies. The investigated drenched or equilibrium solubility data was applied to ascertain the solvation energies. In case of pure solvent, we get the solubility trend of L-phenylalanine as follows: ACN < DMSO < DMF < EG < water, at any temperature. At 298.15 K, we found the solubilities of L- phenylalanine in pure solvents like water, EG, DMF, DMSO and ACN are 0.1675, 0.0911, 0.0888, 0.0850 and 0.0811 mol·kg−1 respectively. A pivotal facet of this study involves the examination of the correlation between the saturated solubility of L-phenylalanine and the intricate characteristics of its solvation energetics across diverse aqueous organic solvent systems.