Journal of Chemical Thermodynamics, Vol.33, No.11, 1587-1596, 2001
Apparent molar volumes and apparent molar heat capacities of aqueous solutions of alpha- and beta-cyclodextrins 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 were determined for aqueous solutions of alpha-and beta-cyclodextrins at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa. The molalities investigated ranged from 0.008 mol . kg(-1) to 0,12 mol . kg(-1) for alpha-cyclodextrin and from 0.004 mol . kg(-1) to 0.014 mol . kg(-1) for beta-cyclodextrin. We used a vibrating-tube densimeter (DMA 512P, Anton PAAR, Austria) to determine the densities and volumetric properties. Heat capacities were obtained using a twin fixed-cell, power-compensation, differential-output, temperature-scanning calorimeter (NanoDSC 6100, Calorimetry Sciences Corporation, Spanish Fork, UT, USA). Equations were fit by regression to our experimental (V-phi, T, m) and (C-p,C-phi, T, m) results. Infinite dilution partial molar volumes V(2)degrees and heat capacities C(p,2)degrees were obtained over the range of temperatures by extrapolation of these surfaces to m = 0.