Molecular interactions of 1,2-dihydroxyethyl-3,4-dihydroxyfuran-2-one in aqueous N-cetyl-N,N,N-trimethyl ammonium bromide solutions with reference to manifestation of solvation

Apparent molar volumes (ϕvϕv) and viscosity B-coefficients for 1,2-dihydroxyethyl-3,4-dihydroxyfuran-2-one (ascorbic acid) in (0.001, 0.003, and 0.005) mol · dm−3 aqueous cetrimonium bromide (N-cetyl-N,N,N-trimethyl ammonium bromide) (C19H42BrN) solutions have been determined from solution density, ρ, and viscosity, η, measurements at T = (298.15, 308.15, and 318.15) K as a function of the concentration of ascorbic acid. Within the investigated temperature range, the relation: ϕv0=a0+a1T+a2T2 , hase been used to describe the partial molar volume ϕv0. These results, in conjunction with the results obtained in pure water, have been used to calculate the standard volumes of transfer Δϕv0 and viscosity B  -coefficients of transfer for ascorbic acid from water to aqueous cetrimonium bromide solutions for rationalizing various interactions in the ternary solutions. The structure making or breaking ability of ascorbic acid has been discussed in terms of the sign of (∂2ϕv0/∂T2)P. An increase in the transfer volume of ascorbic acid with increasing cetrimonium bromide concentration has been explained by the Friedman–Krishnan co-sphere model. The activation parameters of viscous flow for the ternary solutions studied have also been calculated and explained by the application of transition state theory. The 3-D representation of the investigated molecules concerned with this paper is shown below for a better understanding.

► ϕv0 values for ascorbic acid indicate the presence of strong solute–solvent interactions.
► B-coefficient values for ascorbic acid also indicate the presence of strong solute–solvent interactions.
► These interactions are further strengthened at higher temperatures and higher concentrations of cetrimonium bromide in ternary solutions.
► This study also reveals that ascorbic acid acts as a structure breaker in the solvent mixtures studied.