Journal of Solution Chemistry最新文献

l-Aspartic acid (ASP) and l-glutamic acid (GLU) in aqueous solution of a food additive, sodium acetate (SA) have been taken for acoustic and conductometric studies. The experimental results are analysed to predict and assess the solvation behaviour and types of interactions occurring in these ternary solutions [ASP/GLU + SA + water]. Compressibility parameters like isentropic compressibility and apparent molar isentropic compressibility along with their values at infinite dilution have been computed. Transfer values and ion pair and triplet interactions have been determined. Other thermodynamic parameters like internal pressure, molar free volume, relative association and acoustic impedance, have also been derived from the acoustic data. Specific conductance values measured experimentally led to the calculation of molar conduction of electric charge. Walden product sheds light on structure building or breaking properties of the amino acids. Gibbs thermodynamic functions predict the spontaneity of ion association process. Arrhenius equation is used to calculate activation energy which is indicative of the formation of high-energy transition state required for migration of ions. Analysis of these results establishes the amino acids as water-structure forming agents and predominance of ion–solvent, ion–ion and ion–hydrophilic interactions in the studied systems.

Fourier transform infrared spectral studies have been carried out on pure 1-propanol (PrOH), pure ethyl acetate (AcOEt), and 1:1 (ethyl acetate: 1-propanol), 1:2, 1:3, 2:1 and 3:1 binary solutions at room temperature. The broad hydroxyl stretching band of pure PrOH has been deconvoluted into six Gaussian profiles which have been assigned to the O–H stretching bands of monomer, open dimer (free and bonded O–H), closed trimer, closed tetramer and closed pentamer units with the aid of density functional theory frequency calculations. The carbonyl stretching bands of monomer and closed dimer of ethyl acetate have also been discussed. The classical and non-classical H-bond interactions of n-mers of 1-propanol with ethyl acetate monomer and dimer in the solutions have been investigated using the frequency shift of the hydrogen bond donor and acceptor bond stretching bands of PrOH and AcOEt. The concentration of PrOH/AcOEt-dependent PrOH n-mer-AcOEt complexation order has been analysed.

May and Filella (J Solution Chem 52:754–761, 2023) concluded that they had verified the data in Gamsjäger et al. (Chemical thermodynamics of tin OECD, Nuclear Energy Agency Data Bank, Leoben, 2012). However, they used exactly the same primary data and not surprisingly came up with essentially the same values. They (1) provided no new data; (2) did not comment on/re-evaluate the existing experimental data (e.g., Sn–Cl complexes) that determine the accuracy of the E⁰ value for the (Sn⁴⁺/Sn²⁺) couple, but instead relied on a calculated value that is precise but of questionable accuracy; (3) disregarded extensive cassiterite (SnO₂(cass)) solubility data that is critical to (a) ascertaining the accuracy of the E⁰ value based on ({mathrm{Sn}(mathrm{Cl})}_{y}^{4-mathrm{y}}) complexes presented in Gamsjäger et al. (2012) and May and Filella (2023), (b) determining the solubility product of SnO₂(cass), and (c) determining reliable overall K⁰ values for SnO₂(s) solubility reactions involving ({mathrm{Sn}(mathrm{OH})}_{n}^{4-n}) instead of Sn⁴⁺; and (4) in no way help resolve the many orders of magnitude differences in reported K⁰ values for various Sn(IV)–OH system reactions. These issues were extensively addressed in Rai (J Solution Chem.51:1169–1186, 2022) and are briefly discussed herein, and they help to determine that, contrary to May and Filella’s (2023) conclusions, the Sn(IV)–OH system thermodynamic constants presented in Rai (2022) are indeed reliable.