Reaction kinetics and solubility in water-organic binary solutions are governed by similar solvation equilibria

Abstract

aThe solvation effects observed in water-organic solutions were studied by combining data for reaction kinetics and dissolution equilibria by means of a linear free-energy (similarity) analysis. Kinetic data for the pH-independent hydrolysis of (4-methoxyphenyl)-2,2-dichloroacetate measured in this work and solubility data for naphthalene, and other substrates of low polarity, in aqueous binary mixtures of methanol, ethanol, acetonitrile, dimethyl sulfoxide (DMSO), and 1,4-dioxane were used. Linear similarity relationships were discovered for these data over the full range of solvent compositions studied. To gain insight into the similarities observed between these different phenomena, molecular dynamics simulations were carried out for naphthalene and an ester in water-acetonitrile solutions. The results revealed considerable preferential solvation of these substrates by the co-solvent. Linear relationships between the experimental data and the mole fractions of acetonitrile in the solvation shells of substrates were found. Surprisingly, a linear relationship was found between the mole fractions of acetonitrile in the solvation shells of the ester and naphthalene. This linearity indicated that a similar solvation mechanism governs even such different phenomena as dissolution and reaction kinetics. The relationships between the experimental data and the results of the molecular dynamics calculations found in this work explained the solvent effect observed in water-organic solutions on the molecular level.

The Solvation Shell of Small Solutes in Aqueous–Organic Solvent Mixtures and Its Implications for Reversed-Phase Liquid Chromatography

“…As the PS of solutes in the kind of W–OS and OS–OS mixtures that are used as mobile phases in RPLC, HILIC, and NPLC has been reported for decades, − the PS of analytes in the bulk liquid mobile phase is probably the rule rather than the exception. In the chromatographic literature, the consequences of PS have only been considered for solvatochromic indicators. , Their PS is viewed as problematic because it compromises their ability to reflect bulk liquid properties, specifically the elution strength of the mobile phase.…”

New Screening Protocol for Effective Green Solvents Selection of Benzamide, Salicylamide and Ethenzamide

“…Hence, theoretical screening enabling the rational selection of the most promising candidates seems indispensable. Unfortunately, despite great efforts [ 18 , 33 , 40 , 45 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ], there is no universal and reliable way of predicting solubility in binary aqueous solutions from the molecular structure. Methods developed for proper back-computations of measured solubility data such as Jouyban-Acree, van’t Hoff-Yaws, Wilson, Apelblat, Buchowski-Ksiazczak and Non-Random Two Liquid (NRTL) are interesting from the thermodynamic interpretation viewpoint [ 45 , 61 , 62 , 63 , 64 ], however rather of limited applicability as screening tools.…”

Understanding the Influence of the Electrochemical Behavior of Potassium Hexacyanoferrate(II/III) on Acetonitrile/Water Binary Mixtures: An Experimental and Molecular Dynamics Study

“…Water and acetonitrile (ACN) binary mixtures are widely used in many fields of chemistry such as molecular biology, organic synthesis, chromatography, electrochemistry, and solvent extraction . Water is a polar protic solvent able to provide H + by autoprotolysis, and ACN is a polar aprotic solvent.…”