Viscosities of Some Saccharides in Aqueous Solutions of Phosphate-Based Inorganic Salts

Abstract

The viscosities η of some monosaccharides, their methyl- and deoxy- derivatives, disaccharides, and trisaccharides have been measured in (0.25, 0.5, 1.0, and 1.25) mol·kg–1 aqueous solutions of potassium phosphate (KH2PO4) and (0.5, 1.0, 1.5, and 2.0) mol·kg–1 aqueous solutions of sodium phosphate (NaH2PO4) and ammonium phosphate (NH4H2PO4) monobasic salts, and potassium phosphate (K3PO4) tribasic salt over the temperature range (288.15 to 318.15) K and at atmospheric pressure, P = 0.1 MPa. The viscosity data have been utilized to calculate the Jones–Dole viscosity B-coefficients and their corresponding coefficients of transfer, Δt B. The Δt B values were found to be positive and their magnitudes vary depending on the nature of solutes and cosolutes. The dB/dT coefficients and pair ηAB and triplet ηABB interaction coefficients have also been calculated and discussed in terms of solute–solvent/cosolute interactions. The results have been compared in phosphate-based salts on the basis of the nature of the cation and anion.

Influence of Phosphate-Based Salts on Enthalpy of Dilution and Isentropic Compressibility Properties of Saccharides and Their Derivatives in Aqueous Solutions

“…In most of the solutes (except for Raf), the Δ t K ° s,2 values in various salts follow the order NH 4 H 2 PO 4 > K 3 PO 4 > NaH 2 PO 4 > KH 2 PO 4 > CH 3 COONa (organic salt), indicating that phosphate anions undergo higher hydration as compared to acetate anions . The Δ t K ° s,2 results are in line of volumetric, , viscometric, and calorimetric studies that saccharides and their derivatives act as structure makers in mixed aqueous solutions.…”

“…These results indicate that phosphate salts enhance the overall structural order due to the hydrophilic–ionic type of interactions between polar sites of the saccharide molecules and ions of the salts. The volumetric and viscometric properties − also suggest that the saccharides and their derivatives behave as structure makers in mixed aqueous solvent. These studies also support the view of higher structure-making nature of K 3 PO 4 due to more hydration of triply charged PO 4 3– anions than singly charged H 2 PO 4 – anions.…”

“…Very few studies − on the solution behavior of saccharides in the presence of monobasic salts, that is, NaH 2 PO 4 , NH 4 and H 2 PO 4 , and tribasic salts, that is, K 3 PO 4 , are available in the literature. Therefore, to elucidate the interactions among saccharides and phosphate salts, various physicochemical techniques − such as densimetry, viscometry, calorimetry, and sound velocity measurements are being employed. There is only single report on K ° s,2 values of 2de-Glc at 298.15 K …”

Role of the triple solute/ion/water interactions on the saccharide hydration: A volumetric approach

“…where S S * is the experimental slope (in cm 3 kg mol -2 ). The standard partial molar volume of the saccharide, V 0 F;S , characterizes the solute-solvent interactions since solute-solute interactions are negligible at infinite dilutions [41].…”

The effect of saccharides on equilibrium swelling of thermo-responsive gels

“…Although this parameter depends slightly on temperature, 59 we disregard this dependence, as an appropriate activation energy is lower (by at least an order of magnitude) than the enthalpy characterizing the effect of T on χ 13 (see Fig. S-3, † where experimental data 60 on aqueous solutions of glucose and sucrose are presented).…”