Journal of Chemical Thermodynamics, Vol.112, 13-22, 2017
Volumetric, viscometric and H-1 NMR spectroscopic studies in (polyhydroxy solute + CTAB + H2O) ternary solutions
To investigate the molecular interactions of polyhydroxy solutes with cetyltrimethylammonium bromide (CTAB) surfactant, we have measured the densities and viscosities of (+)-D-xylose, xylitol, (-)-L-sorbose, o-sorbitol, (+)-D-glucose, and (+)-D-maltose in (4.0, 8.0, and 12.0) . 10(-4) mol.kg(-1) CTAB((aq)) solutions at (298.15, 308.15 and 318.15) K. The density data have been utilized to evaluate apparent molar volumes (V-2,V-phi), partial molar volumes (V-2 degrees) and their transfer (Delta V-t(2)degrees) values at infinite-dilution. The viscosity data were analyzed using the Jones-Dole equation and further used to calculate the viscosity B-coefficients and transfer B-coefficients, Delta B-t. The structure-making/-breaking behavior of the polyhydroxy solutes were analyzed using the signs and magnitude of (partial derivative V-2(2)degrees/partial derivative T-2)(P) and dB/dT coefficients. It has been observed that the positive AtV2 and Ad3 values increase with increasing CTAB concentration. H-1 NMR spectroscopic study of polyhydroxy solutes was also carried out in m(B) = (4.0, 8.0, and 12.0) . 10(-4) mol.kg(-1) CTAB solutions which were made in 9:1 (w/w) H2O + D2O solvent. NMR results showed higher downfield shift in ternary (polyhydroxy solute + CTAB + 9:1 (w/w) H2O + D2O) solutions as compared to pure CTAB solution, hence suggested the predominance of hydrophilic-ionic interactions over hydrophobic-ionic interactions. (C) 2017 Elsevier Ltd.
Keywords:Polyhydroxy compound;Cetyltrimethylammonium bromide;Standard partial molar volume;Viscosity B-coefficient;Stereochemical effect