Low-temperature vapor-liquid phase data are reported for the carbon monoxide-propane and the carbon monoxide-ethane systems. The data for the carbon monoxide-propane system are reported a t eight temperatures ranging from -125" to +50°C., with pressure up to 2,000 Ib./sq. in. abs., those for the carbon monoxide-ethane system are reported at four temperatures from -100" to O"C., with pressures ranging up to the critical locus. Liquid phase immiscibility was observed a t low temperatures in both the carbon monoxide-ethane and the carbon monoxide-propane systems. The pressure-temperature loci for these two systems in liquid-liquid vapor equilibrium were determined.This study was undertaken to provide additional lowtemperature vapor-liquid phase data for the carbon monoxide-propane and the carbon monoxide-ethane systems.Limited vapor-liquid data have been previously reported for the carbon monoxide-propane system ( 8 ) , but no data for the carbon monoxide-ethane system were found in the literature. Vapor-liquid data for the carbon monoxidemethane system have been reported (6). At low temperatures liquid phase immiscibility was observed in both the carbon monoxide-propane and the carbon monoxide-ethane systems. Pressure-temperature loci for these two systems are reported.
E X P E R I M E N T A L METHODThe apparatus and method used in this study have been described previously ( 4 ) . Samples of vapor and liquid were taken from a magnetically stirred, static equilibrium cell which was maintained in a constant-temperature bath. Bath temperatures were measured and controlled to within + O.O5"C., and the pressures are believed to be within +3 lb./sq. in. of reported values. Three vapor samples and three liquid were removed from the equilibrium cells and analyzed by gas chromatography. During sampling the pressure drop was never greater than 5 to 10 lb./sq.in.A visual glass cell was used for determining the pressuretemperature loci in the region of liquid phase immiscibility.The carbon monoxide used in this study was Matheson Pure Grade, with a purity of 99.8%. Impurities in the carbon monoxide were 0.17% nitrogen and 0.04% carbon dioxide. The propane and ethane were Phillips Instrument Grade and Pure Grade, respectively. Hydrocarbon purities, as determined by chromatographic analyses, were propane, 99.9% and ethane, 99.1%. Impurities in the propane were nitrogen, methane, and ethane. Impurities in the ethane were nitrogen and methane.
EXPERIMENTAL DATA Carbon Monoxide-Propane SysiemQualitatively, the phase behavior of the carbon monoxidepropane system is very similar to the nitrogen-propane system studied by Schindler
