Measurements of vapor pressures and boiling points, over the range 47 to 780 millimeters of mercury and above ah>out 12° C, were made on 52 purified hydrocarbons. The apparatus consisted of an electricaUy heated boiler, a vapor space with a vertical reentrant tube containing a platinum thermometer having a resistance of 25 ohms, and a condenser. Measurements of the temperature of the liquid-vapor equilibrium were made at 20 fixed pressures maintained automatically. The values of the fixed pressures were determined by calibration of the apparatus with water by using the vapor pressure-temperature tables prepared at the National Bureau of Standards.The experimental data on the hydrocarbons were correlated, the method of least squares being used, with the three-constant Antoine equation for vapor pressures, log P=A-B/(C+t) or t=B/(A-Iog P)-C. Experimental data, together with the values of the three constants of the Antoine equation, applicable over the range of measurement, are reported for 30 paraffin, 4 alkylcyclopentane, 10 alkylcyclohexane, and 8 alkylbenzene hydrocarbons.

This report gives the results of the purification and measurements of r efractive index (nD at 20° and 25° C), density (at 20° and 25° C), boiling point and pressure coeffi cient of t he boiling point (at 1 atm) and, except for four of the compounds, tije freezing point, t ogether wit h the calculated amount of impurity, of samples of 51 hydrocarbons, including 29 paraffins, 4 alkylcyclopentanes, 10 alkylcyclohexanes, and 8 alkylbenzenes.

This r eport describes the purification and determination of freezing points and purity of 37 hydrocarbons of the API-Standard and API-NBS series, including 7 heptanes, 16 octanes, 6 pentenes, cyclopentene, and 7 CgH 12 alkylbenzenes.

To obtain information about the chemical constitution of the extract portion of the lubricant fraction from a midcontinent petroleum, fifteen selected fractions, prepared by extensive distillation and extraction, were completely hydrogenated. The hydrogenation procedure is described and there are tabula.ted and compared values for the physical constants of the fractions before and after hydrogenation. Evidence is presented to show that, under the conditions of these experiments, namely, temperatures from 230 0 to 250 0 C and pressures of hydrogen from 170 to 210 atm, the fractions were completely hydrogenated and that no breakdown of the molecules occurred. CONTENTS

No abstract