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

Vapor-liquid equilibria data for the hydrogen-propane binary system and the hydrogencarbon monoxide-propane system were taken at temperatures of -185" to +75"C. and under pressures as high as 3000 psi, Vapor-liquid data for the hydrogen-carbon monoxide-propane system are reported at -No, 0", and +50"C. at pressures of 500, 1000, and 2000 Ib./sq.in. abs.for each of the three temperatures. The Krichevsky-Kasarnovsky equation adequately correlated the solubility data of hydrogen in the liquid phase of the hydrogen-propane system. Hydrogenpropane data are compared with the data of two previous studies.Experimental data were collected in order to test empirical and semiempirical methods for the prediction of phase behavior and to confirm and to fill in gaps existing in previous data. Although the theoretical approach to this problem is not sufficiently developed for the conditions of this study, the data should be useful in the development and testing of future theories.Additional data* on the hydrogen-propane binary system and the hydrogen-carbon monoxide-propane ternary system are provided because low temperature phase behavior data are necessary for the evaluation of cryogenic purification processes for hydrogen. Phase data for the hydrogen-carbon monoxide-propane ternary system are based on those of Stein, Claitor, and Geist (1 ) . Their data are limited to a single temperature of -187.5"C. under a maximum pressure of 475 Ib./sq. in. abs. The hydrogenpropane system has been studied by Burriss e t al. (2) and by Williams and Katz (3). The former study was carried out under 8000 lb./sq. in. abs. between 4.4" and 8 7 3°C . In the latter study the maximum pressure was 8000 Ib./ sq. in. abs., and the temperature range, from -184" to +23.9"C. E X P E R I M E N T A L METHODThe apparatus and method have been described by Sinor et al. which the cell was contained could be maintained at a constant temperature over the range of -196" to +85"C. by balancing the cooling effect of liquid nitrogen coolant with a controlled electrical heat input. The temperature levels of the equilibrium cell were controlled and measured to within -cO.O5"C.A platinum resistance thermometer, the sensing element, was calibrated against a laboratory standard platinum resistance thermometer which, in turn, had been calibrated by the National Bureau of Standards. Pressures were measured with Heise bourdon tube gages, which were calibrated with a Ruska pressure balance. The accuracy of the pressure measurements is believed to be within 2 3 Ib/sq.in. of reported values.Samples withdrawn from the equilibrium cell were passetl directly to a F I% M Model 720 chromatograph for analysis. Chromatographic responses for the unknown samples werr compared to responses of known samples that had been prcpared by mixing pure component gases at measured pressures into five mixing vessels. During sampling the pressrirr drop was reduced by minimizing the "dead volume" in the sampling system and by removing for analyses three duplicates each of small liquid and vapor s...