Vapour pressure and excess Gibbs free energy of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane at temperature of 182.33 K

The vapour pressure of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane was measured at T = 182.33 K covering most of the composition range. The excess Gibbs free energy of these mixtures has been derived from the measurements made. For the equimolar mixtures GmE(x1=0.5)=(835.5±5.8)J·mol-1 for (H2S + C2H6), (820.1 ± 2.4) J · mol−1 for (H2S + C3H8), and (818.6 ± 0.9) J · mol−1 for (H2S + n-C4H10). The binary mixtures of H2S with ethane and with propane exhibit azeotropes, but that with n-butane does not.