TITLE:
Predicting the Enthalpy of Vaporization and Calculating the Entropy of Vaporization of 87 Octane Gasoline Using Vapor Pressure
AUTHORS:
Shawn M. Abernathy, Kelly R. Brown
KEYWORDS:
Gasoline, Vapor Pressure (VP), Enthalpy of Vaporization, Entropy of Vaporization, Volatile Organic Compounds (VOCs)
JOURNAL NAME:
Open Access Library Journal,
Vol.3 No.9,
September
13,
2016
ABSTRACT: The vapor pressure (VP) of 87 grade gasoline was measured using an enhanced VP acquisition system over a temperature range of approximately 19.0℃ (292.2 K) and 69.0℃ (342.2 K). The empirical data were used to predict the thermodynamic entities the enthalpy of vaporization (ΔHvap) and the entropy of vaporization (ΔSvap) of gasoline. The results of this investigation yielded a ΔHvap value of 35.1 kJ/mol and ΔSvap of 102.5 J/mol·K. The value of ΔHvap was in excellent agreement with the findings of a prior study (Balabin et al., 2007), which produced a ΔHvap values of 37.3 kJ/mol and 35.4 kJ/mol. The enthalpy and entropy of vaporization of n-heptane (37.2 kJ/mol and 100.1 J/mol·K) and n-octane (39.1 kJ/mol and 98.3 J/mol·K) were also determined after acquiring VP data for the two VOCs. The empirical results for n-heptane and n-octane were also in excellent agreement with the literature. These favorable comparisons strengthen the capacity of our system for acquiring the VP data for pure and volatile multi-component mixtures.