SUBAMBIENT APPLICATIONS OF DIFFERENTIAL THERMAL-ANALYSIS FOR THE DETERMINATION OF VAPOR-PRESSURE

Differential thermal analysis (DTA) has been shown to be a useful technique for determining the vapor pressure of pure liquids. Incorporation of a subambient cooling accessory into existing commercial instrumentation allows rapid determination (in less than 2 h) of vapor pressure curves of pure liquids over wide pressure (5-760 Torr) and temperature (- 180-450-degrees-C) ranges using a small amount (less than 1 ml) of sample. Vapor pressure curves of several compounds, for which only atmospheric pressure boiling points were available, have been established with this technique.