Molar Heat Capacity of Aqueous Sulfolane, 4-Formylmorpholine, 1-Methyl-2-pyrrolidinone, and Triethylene Glycol Dimethyl Ether Solutions from (303.15 to 353.15) K

The present study has focused on the experimental measurements of the molar heat capacities of four aqueous physical solvents of importance in natural gas sweetening: (1) tetramethylene sulfone (sulfolane), (2) 4-formylmorpholine (NFM), (3) 1-methyl-2-pyrrolidinone (NMP), and (4) triethylene glycol dimethyl ether (TEGDME). The measurements of the molar heat capacities were carried out in the temperature range of (303.15 to 353.15) K and for the entire range of mole fractions. Fractional deviations of the measured molar heat capacities from literature data were less than 1 %, and at worst 2 %. Molar excess heat capacities were calculated from the measurements and correlated as a function of mole fraction and temperature employing the Redlich−Kister equation. The excess partial molar quantities ( C i o − C i * ) were calculated by extrapolating the reduced excess heat capacity ( C p E / x 1 x 2 ) function at x 1 = 0 and x 1 = 1.