Rheological behaviour of some saccharides in aqueous potassium chloride solutions over temperature range (288.15 to 318.15) K

The viscosities, eta of mono-, di-, tri-saccharides and methylglycosides, viz., D(+)-xylose (XYL), D(-)-arabinose (ARA), D(-)-ribose (RIB), D(-)-fructose (FRU), D(+)-galactose (GAL), D(+)-mannose (MAN), D(+)-glucose (GLU), D(+)-melibiose (MEL), D(+)-cellobiose (CEL), pH-lactose monohydrate (LAC), pH-maltose monohydrate (MAL), D(+)-trehalose dihydrate (TRE), sucrose (SUC). D(+)-raffinose pentahydrate (RAF), alpha-methyl-D(+)-glucoside (alpha-Me-GLU), methyl-alpha-D-xylopyranoside (Me-alpha-XYL), and methyl-beta-D-xylopyranoside (Me-beta-XYL) in water and in (0.5, 1.0, 2.0, and 3.0) mol center dot kg(-1) aqueous solutions of potassium chloride (KCl) have been determined at T = (288.15, 298.15. 308.15, and 318.15) K from efflux time measurements by using a capillary viscometer. Densities used to determine viscosities have been reported earlier. The viscosity data have been utilized to determine the viscosity B-coefficients employing the Jones-Dole equation at different temperatures. From these data, the viscosity B-coefficients of transfer, Delta B-t have been estimated for the transfer of various saccharides/methylglycosides from water to aqueous potassium chloride solutions. The Delta B-t values have been found to be positive, whose magnitude increases with the increase in concentration of potassium chloride in all cases. The dB/dT coefficients, pair, eta(AB) and triplet, eta(ABB) viscometric interaction coefficients have also been determined. Gibbs free energies of activation and related thermodynamic parameters of activation of viscous flow have been determined employing Feakin's transition-state theory. The signs and magnitudes of various parameters have been discussed in terms of solute-solute and solute-solvent interactions occurring in these solutions. The effect of substitution of -OH by methoxy group, -OCH3 has also been discussed. (C) 2010 Elsevier Ltd. All rights reserved.