Thermodynamic properties of propanol using DFT in the gas phase

Abstract

Abstract This study aims to assess the impact of thermodynamic properties of propanols (propan-1-ol, propan-2-ol) and their isomers (2-methylpropan-1-ol and 2-methylpropan-2-ol) on fuel mixtures with gasoline, diesel, and kerosene. The evaluation is conducted using the Functional Density Theory, which determines various thermodynamic properties like specific molar heat at constant pressure, entropy, Gibbs free energy, and variation of formation enthalpy for calculating the heat of combustion. The simulation is performed using the functional hybrid B3LYP structures with bases 6–311 + + g (d, p) and 6-31g (d) through the software Gaussian 09W and the semi-empirical method PM3. Notably, 2-methylpropan-1-ol and 2-methylpropan-2-ol show higher energy gains, generating 13.38 KJ/g and 13.88 KJ/g more energy per unit mass compared to ethanol (22.73 KJ/g) and methanol (12.70 KJ/g), respectively. As the fraction of propanols increases by 10%, propan-1-ol with 33.49 KJ/g and propan-2-ol with 33.53 KJ/g exhibit the highest energy losses when compared to gasoline, which recorded 13.81 KJ/g and 13.77 KJ/g, respectively, under similar pressure and temperature conditions. The combustion of propan-1-ol shows the lowest values in all scenarios, particularly with diesel fuel at 11.31 KJ/g and kerosene at 12.71 KJ/g. Additionally, the study highlights the potential of these propanol-based mixtures as viable alternatives in the combustion phase, offering potential benefits in terms of energy efficiency and reduced emissions.