Rapid measurements of boiling point and vapor pressure of short-chain triglycerides by thermogravimetric analysis

Temperature dependence of vapor pressure and the boiling points for tricaproin (Tcap) and tricaprylin (Tcpy) were measured by a new rapid thermogravimetric analysis (TCA) method. Results were in agreement with data from other references. The Clausius/Clapeyron model fitted Tcap and Tcpy vapor pressure data with errors of 6% or less for pressures rang ing from ambient down to 20 mmHg. This agreement with the model suggests that the vapor of these compounds has a large degree of ideal gas behavior and that their vaporization enthalpies are nearly constant from 25 to 400 degrees C. Comparable accuracy and precision were obtained with TCA and differential scanning calorimetry methods fbr the compounds tested; however, TCA plots had significantly straighter baselines, which made vapor pressure determinations more convenient.