Vapour pressure and gas solubility measurements for terphenyls at high temperatures

Abstract

AbstractAn apparatus is described for the measurement of vapour pressures at temperatures up to 400° and pressures up to 8 atmospheres. The same apparatus can also be used to measure gas solubilities in liquids of appreciable vapour pressure over a similar working range. Vapour pressure measurements are reported for Santowax R (a commercial terphenyl) and for its mixture with diphenyl in the temperature range 200°–400°: Raoult's law is shown to apply to these results. The solubilities of hydrogen, helium, nitrogen and methane in Santowax R were determined for gas pressures between 100 and 400 cm. and at temperatures between 220° and 400°. The surface tension of Santowax R was measured in the range 150°–250°. These data have made possible a test of the Burrows & Preece treatment of gas solubilities over a much wider temperature and pressure range than has previously been reported. Earlier predictions about the effect of temperature on the solute‐solvent interaction term (‐ΔEA) are confirmed.