| Abstract
| - The heat capacities (Cp) of ethanol, unleaded gasoline 93# (where the “93” represents the octanenumber), and gasohol (which consisted of 10 wt % ethanol and 90 wt % unleaded gasoline 93#)were measured by adiabatic calorimetry in the temperature range of 80−320 K. For the gasoline,a glass−liquid transition was found at 92.42 K; for the gasohol, a glass−crystal transition anda solid−liquid transition were observed, at 93.17 and 150.86 K, respectively. The enthalpy andentropy of all of the transitions were derived based on the Cp data. For the gasoline, the enthalpyand entropy of the glass-liquid transitions were determined to be 6.80 J g-1 and 0.0736 J K-1g-1, respectively; for the gasohol, the enthalpy and entropy of the glass−crystal transition weredetermined to be 9.93 J g-1 and 0.107 J K-1 g-1 , respectively, and the enthalpy and entropy ofthe solid−liquid phase transition were determined to be 9.99 J g-1 and 0.0662 J K-1 g-1,respectively. The polynomial equations of Cp, with respect to the thermodynamic temperatureT, were established through the least-squares fitting. According to the thermodynamic relationshipand the equations, the thermodynamic functions of the gasoline and the gasohol, and the excessthermodynamic functions of the gasohol, were derived.
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