The entropy and related thermodynamic properties of propionitrile
Weber, Lloyd Adolph, Jr
Doctor of Philosophy
The purpose of this investigation was the calorimetric determination of the saturated heat capacity and the heats and temperatures of all phase transitions of propionitrile (ethyl cyanide) from about 15°K to room temperature. From this data, and gas imperfection data available in the literature, the entropy of this compound was calculated in the ideal gas state. This value was then compared with the entropy calculated from Raman and infrared spectroscopic data. Agreement between the two methods may be used as a check on the molecular model used and on the accuracy of the calorimetric data. No experimental value for the entropy of propionitrile has been reported. Janz and Duncan have calculated a value from spectroscopic data. There is some room to doubt the validity of their calculations, however, as will be shown in the section on the entropy. The Raman and infrared spectra have been measured by several authors. Lerner and Dailey and Laurie have reported the microwave spectrum with values for the principal moments of inertia and the torsional frequency. The sample used in this research was found to contain an appreciable amount of solid soluble impurity. Putnam investigated the effects of this type of impurity on sharpness of melting data. However, his results were not completely satisfactory, and this analysis was extended to include premelting heat capacity data.