Densities of glycine,L-alanine and L-serine in various aqueous D-xylose solutions were measured at 298.15 K by an Anton Paar Model 55 densimeter.Apparent molar volumes,limiting partial molar volumes and hydration numbers for these amino acids were calculated.The transfer volumes from water to aqueous(D-xylose) solutions were obtained and discussed in terms of the structural hydration interaction model.The results show that all of the transfer volumes are positive,and increase with increasing xylose concentration;the side-chain contributions to the transfer volumes are highly related to the nature of side-chain groups;the hydration numbers for the three amino acids in solutions decrease with increasing xylose concentration.
The dilution enthalpies of formamide in aqueous ethylene glycol solutions were determined by using a CSC- KG-1/54400 isothermal calorimeter at 298.15 K. The homogeneous enthalpic interaction coefficients in the range of ethylene glycol mass fraction（0%\40%） were calculated according to the excess enthalpy concept. The results show that enthalpic pair interaction coefficients h 2 of formamide are negative in aqueous ethylene glycol solutions and pass through a minimum at w≈0.20 of ethylene glycol in mixed solvents.
