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Volumetric Properties and Viscosity B-Coefficients for the Ternary Systems Epigallocatechin Gallate + MCl + H2O (M = Li, Na, K) at Temperatures 288.15–308.15 K

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journal contribution
posted on 2016-03-29, 18:50 authored by Dawei Li, Guangqian Li, Pingfeng Bian, Zhe Shen, Mengfan Fu, Wenjun Fang, Weidong Yan
Epigallocatechin gallate (EGCG) is the most abundant and active components in tea. In this text, the density and viscosity of ternary aqueous solution of EGCG containing LiCl/NaCl/KCl were determined at temperatures ranging from 288.15 to 308.15 K at atmospheric pressure. The density data was used to compute the apparent molar volumes (Vφ), limiting partial molar volumes (Vφ0), and transfer partial molar volumes (ΔtrsVφ0). The viscosity B-Coefficients were calculated from the measured viscosity data using the extended Jones–Dole equation. The values of density and viscosity increased continuously with the increasing of molality of EGCG and decreased with the temperature increasing. The positive values including (Vφ, Vφ0, ΔtrsVφ0, viscosity B-Coefficients, the free energies of activation for solvent Δμ10≠, and for solute Δμ20≠) and Helper’s constant (∂2Vφ0/∂T2)p close to zero indicated the presence of strong solute–solvent interactions and the structure–making effect of EGCG in the investigated solutions. The apparent molar isobaric expansions (Eφ0) decreasing with temperature suggested that the solute–solvent interactions became weaker as temperature increased. These significant parameters could provide necessary data about molecular interactions occurring in simulated body fluids.

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