The vapor-liquid equilibrium (VLE) and the saturated liquid density were measured for three binaries, propane + dimethyl ether (DME), DME + butane, and propane + butane, and the ternary, propane + DME + butane, at 313.15 +/- 0.03 K. The apparatus was based on a recirculation method and incorporated an oscillation U-tube densimeter. Deviation of the saturated vapor pressure for pure propane, DME and butane were 0.556, 0.525, and 6.210 %, respectively, and that for the saturated liquid density for DME was 0.552 %, compared with the reported values. The experimental binary VLE data for propane + DME, DME + butane and propane + butane, agreed with reported values. The data were correlated with the prediction of the Benedict-Webb-Rubin (BWR) equation of state. The constants in the BWR equation for DME were determined in our previous research, and those for propane and butane were obtained from the literature. The correlation showed a good reproducibility. The averaged absolute deviations (AADs) for the mole fractions in the liquid and vapor phases were 2.156 % and 1.687 %, respectively, and for the saturated liquid density was than 1.490 %. The ternary VLE and the saturated liquid density was measured at 0.8830 MPa and 313.15 K. The VLE and the saturated liquid density were estimated by the BWR equation using only the binary parameters. The AADs for the mole fractions in the liquid and vapor phases were 2.905 % and 2.110 %, and that for the saturated liquid density was 1.432 %.
