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

The viscosities, η 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), d(+)-lactose monohydrate (LAC), d(+)-maltose monohydrate (MAL), d(+)-trehalose dihydrate (TRE), sucrose (SUC), d(+)-raffinose pentahydrate (RAF), α-methyl-d(+)-glucoside (α-Me-GLU), methyl-α-d-xylopyranoside (Me-α-XYL), and methyl-β-d-xylopyranoside (Me-β-XYL) in water and in (0.5, 1.0, 2.0, and 3.0) mol · 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, ΔtB have been estimated for the transfer of various saccharides/methylglycosides from water to aqueous potassium chloride solutions. The ΔtB 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, ηAB and triplet, ηABB 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.