Heat capacities and volumes of mixtures of N,N-dimethylformamide with isobutanol, sec-butanol and t-pentanol. An analysis of the water–non-electrolyte enthalpic pair interaction coefficients in N,N-dimethylformamide solution

Abstract

Heat capacities and densities of mixtures of N,N-dimethylformamide (DMF) with isobutanol, sec-butanol and t-pentanol have been determined over the complete mole fraction range. From these data, partial molar heat capacities and volumes for both components have been calculated. The partial molar quantities in isobutanol–DMF and sec-butanol–DMF mixtures are smooth functions of the mole fraction, while the partial molar volume and partial molar heat capacity of DMF in the mixture with t-pentanol exhibit extrema in the alkanol-rich region. Heat capacities of transfer of some non-electrolytes from the gas phase to DMF at infinite dilution have been calculated and correlated with the enthalpic pair interaction coefficients for pairs of molecules of water and these non-electrolytes dissolved in DMF. Unlike in aqueous solution, the correlation in DMF is valid only for non-electrolytes with comparable properties and molecular structure.