Solute-solvent and solvent-solvent interactions and preferential solvation of limonin in aqueous co-solvent mixtures of methanol and acetone

2018 ◽  
Vol 263 ◽  
pp. 357-365 ◽  
Author(s):  
Wanxin Li ◽  
Shuo Qi ◽  
Nan Wang ◽  
Zhenghao Fei ◽  
Ali Farajtabar ◽  
...  
Keyword(s):  
Preferential Solvation ◽  
Solvent Mixtures ◽  
Solvent Interactions ◽  
Solvent Solvent

scholarly journals Preferential solvation of quercetin in aqueous aprotic solvent mixtures

2020 ◽  
Vol 85 (2) ◽  
pp. 227-236
Author(s):  
Mohammad Faraji ◽  
Ali Farajtabar
Keyword(s):  
Aprotic Solvent ◽  
Linear Trend ◽  
Bulk Composition ◽  
Preferential Solvation ◽  
Great Influence ◽  
Solvation Shell ◽  
Solvent Mixtures ◽  
Solvent Interactions ◽  
Spectral Shifts ◽  
Solvent Solvent

Solvatochromism of quercetin was studied in binary mixtures of water with dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide at 25 ?C by UV?Vis measurements. For all mixtures, a non-linear trend was observed in spectral shifts plotted against the bulk mole fractions. Deviation from ideal behaviour indicates that the solvation shell of quercetin differs in composition from the bulk because of preferential solvation. The solvent exchange model was applied in the analysis of solvatochromic data in order to quantify the extent of preferential solvation in the case of solute?solvent and solvent?solvent intermolecular interactions. The results show that the solvation shell of quercetin is enriched in aprotic solvent and the complex that was formed by the interaction between water and an aprotic solvent, over the whole composition range. The distribution of the solvent species in the solvation cage was obtained from the calculation of the local mole fractions as a function the bulk composition. It shows that the solvent?solvent interactions have great influence on the solvation behaviour of quercetin in aqueous aprotic solvent mixtures.

Modeling Gel Swelling in Binary Solvents: A Thermodynamic Approach to Explaining Cosolvency and Cononsolvency Effects

2019 ◽  
Vol 11 (05) ◽  
pp. 1950050 ◽  
Author(s):  
Rui Xiao ◽  
Jin Qian ◽  
Shaoxing Qu
Keyword(s):  
Lattice Model ◽  
Thermodynamic Theory ◽  
Binary Solvents ◽  
Thermodynamic Approach ◽  
Solvent Mixtures ◽  
Solvent Interactions ◽  
Equilibrium Swelling ◽  
Acceptable Agreement ◽  
Swelling Behaviors ◽  
Solvent Solvent

If gel swells in binary solvents, two unusual phenomena may appear. Two solvents with relatively low swelling ability may become a good solvent for the polymer with high swelling ability when mixed, which is known as a cosolvency effect. In contrast, a cononsolvency effect indicates polymer is less soluable in solvent mixtures than it is in each of the cosolvents. In this work, we develop a thermodynamic theory to describe the equilibrium swelling behaviors of gels in binary solvents based on the Flory–Huggins lattice model. The model can reproduce both cosolvency and cononsolvency effects, showing that these effects are caused by the preferential absorption of the solvent by polymer together with solvent–solvent interactions. The model is also applied to describe experimentally observed cosolvency and cononsolvency effects in the literature, which shows an acceptable agreement.

Sign in / Sign up

Export Citation Format

Share Document