Vapor pressures and boiling points of sixty API-NBS hydrocarbons

Abstract

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 temperat ure of the liquid-vapor equilibrium were made at 20 fixed pressures maintained automaticall y. 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/(A-log P)-C. Experimental data, together with the values of the three constants of the Antoine equation applicabl e over the range of measurement, are reported for 60 API-NBS hydrocarbons, including 17 paraffins, 14 alkyJcyclopentanes! 8 aJkylcyclohexa nes, and 21 a lkylbenzenes.