Apparent molar volumes and apparent molar heat capacities of aqueous solutions ofα- andβ-cyclodextrins at temperatures from 278.15 K to 393.15 K and at the pressure 0.35 MPa

Abstract

Apparent molar heat capacities Cp, φand apparent molar volumesVφ were determined for aqueous solutions of α - and β -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−1to 0.12 mol · kg−1forα -cyclodextrin and from 0.004 mol · kg−1to 0.014 mol · kg−1for β -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 (Vφ, T, m) and (Cp, φ,T , m) results. Infinite dilution partial molar volumes V2oand heat capacities Cp,2owere obtained over the range of temperatures by extrapolation of these surfaces to m= 0.