Vapor pressures and boiling points of sixty API-NBS hydrocarbons

Measurements of vapor pressures and boiling points, over the range 48 to 780 millimeters of mercury, and above about 11 0 C, were made on 60 purified hydrocarbons. The apparatus consisted of an electricall y 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 using the vapor pressure-temperature tables prepared at this Burcau. The experimental data on the hydrocarbons were correlated, the method of least squares being u ed, w ith t he three-constant Antoine equation for vapor pressures, log P = A B/ (C+O or I= B/(Alog 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 60 APINBS hydrocarbons, including 17 paraffins, 14 alkyJcyclopentanes! 8 aJkylcyclohexa nes, and 21 alkylbenzenes.