Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

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, D-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 (V2,/), partial molar volumes (V2 ) and their transfer (DtV2 ) 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, DtB. The structure-making/-breaking behavior of the polyhydroxy solutes were analyzed using the signs and magnitude of (o2V2 /oT2)P and dB/dT coefficients. It has been observed that the positive DtV2 and DtB values increase with increasing CTAB concentration. 1H NMR spectroscopic study of polyhydroxy solutes was also carried out in mB = (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.