HEAT-CAPACITY OF LIQUID TERPENES

A differential scanning calorimeter was used for measurements of the h eat capacity of cr-pinene, P-pinene, limonene, and a sample of turpent ine at atmospheric pressure, at temperatures from 313 to 403 K. It was calibrated by measuring the enthalpy of fusion and the temperature of fusion of several pure (99.999%) metals. Repeatability and reproducib ility tests were performed to access the accuracy of the instrument. T he accuracy was confirmed by using standard reference materials like, toluene distilled and dried in molecular sieves, and deionised water, in the temperature range of 300 to 400 K. The results demonstrate that the calorimeter is capable of producing data of enthalpies of fusion with an uncertainty of 1.7%, temperatures of fusion within 0.2 K, and heat capacities with an uncertainty of 1.5%, all at a 95% confidence l evel. (C) 1998 Elsevier Science B.V. All rights reserved.