Understanding the interactions of polyhydroxy solutes with ammonium salts in aqueous solutions via calorimetric and spectroscopic studies at different temperatures

摘要: Abstract Enthalpy change, q of polyhydroxy solutes; (+)- d -xylose, xylitol, (−)- l -sorbose, -sorbitol, -glucose, and -maltose monohydrate have been measured in water aqueous (0.10, 0.15, 0.25, 0.35) mol·kg− 1 ammonium bromide (NH4Br) (0.15, tetraethylammonium (Et4NBr) solutions at T = (288.15, 298.15, 308.15, 318.15) K by using isothermal titration microcalorimeter. From the data q, limiting standard enthalpies dilution (ΔdilH°) their corresponding transfer parameters (ΔtΔdilH°) evaluated. The enthalpic interaction coefficients that characterize interactions solutes with salts were determined from ΔtΔdilH° values. Proton (1H) NMR spectra recorded for mB = (0.15, 0.25 ternary {polyhydroxy solute + Et4NBr + 9:1 (w/w) H2O + D2O}, where molality solute has fixed as mA = 0.25 mol·kg− 1. comparison results shows more upfield shift than pure alkyl salt solution, thereby suggesting predominance hydrophobic-ionic over hydrophilic-ionic interactions.