Propriedades termodinâmicas de propanóis na fase gasosa via DFT

Abstract

The main objective of this study is to evaluate the effect of the thermodynamic properties of propanols propan-1-ol, propan-2-ol and their isomers 2- methylpropan-1-ol and 2-methylpropan-2-ol in addition to elaborating a proposal for mixtures with fuels, gasoline, diesel, and kerosene-based on the Functional Density Theory to determine thermodynamic properties, such as specific molar heat at constant pressure, entropy, Gibbs free energy, a variation of the formation enthalpy for calculating the heat of combustion. The excited state of the propanols and their isomers, applied to their energy figures transferred by the functional hybrid of the B3LYP structures, in the bases 6–311 ++ g (d, p) and 6-31g (d) were simulated using the software package Gaussian 09W and the semi-empirical method PM3. To obtain the physical properties of the chemical reactivity in the gas phase of each component and its combustible isomers, the temperature range of 0.5K - 1500K was used at a constant pressure of 1atm and in a vacuum. The addition of propane and its isomers in the combustion phase provided a greater energy balance as a whole, with 2-methylpropan-1-ol and 2-methylpropan-2-ol generating 13.38 and 13.88 KJ / ga more of gain energy per unit mass than ethanol (22.73 KJ / g) and methanol (12.70 KJ / g), the progressive increase of fractions 10%, demonstrates that propan-1-ol with 33.49 KJ / g and propan-2-ol 33.53 KJ / g, obtained the highest energy losses when compared to gasoline, which reached 13.81 and 13.77 KJ / g respectively in pressures, temperature patterns. TheX combustion of propan-1-ol was the lowest in all events over fractions in the case of diesel fuel 11.31 KJ / g and kerosene 12.71 KJ / g.