Apparent molar volumes and apparent molar heat capacities of aqueous D-glucose and D-galactose at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa

Apparent molar heat capacities C-p,C-phi and apparent molar volumes V-phi w ere determined for aqueous solutions of D-glucose and D-galactose at temper atures from 278.15 K to 393.15 K and at the pressure 0.35 MPa. The molaliti es m investigated ranged from 0.05 mol . kg(-1) to 0.5 mol . kg(-1). A vibr ating tube densimeter (DMA 512P, Anton PAAR, Austria) was used to investiga te the densities and volumetric properties. Heat capacities were obtained u sing a twin fixed-cell, power-compensation, differential-output, temperatur e-scanning calorimeter (NanoDSC 6100, Calorimetry Sciences Corporation, Pro ve, UT, U.S.A). The calculated V-phi and C-p,C-phi Of the solutions were fi t to equations that describe the surfaces (V-phi, T, m) and (C-p,C-phi, T, m). These surfaces showed no dependence of V-phi or C-p,C-phi on M. Infinit e dilution partial molar volumes V-2(o) and heat capacities C-p,2(o) Were o btained over the range of temperature. The C-p,2(o) and V-2(o) values were found to be large, positive, and to increase with increasing temperature. ( C) 2000 Academic Press.