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The standard enthalpies of combustion, formation, fusion, and sublimation of crystalline furan 2 carboxylic and 3 (2 furyl) 2 propenoic acids are determined by experimental methods and recalculated to 298 K. The possibility of using additive calculation schemes based on the principle of group contributions to calculate the standard enthalpies of vaporization and formation of substances with similar combinations of functional fragments in the gas phase is analyzed.

BackgroundThe aim of the current work was to determine thermo dynamical properties of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde.ResultsThe temperature dependence of saturated vapor pressure of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde was determined by Knudsen’s effusion method. The results are presented by the Clapeyron–Clausius equation in linear form, and via this form, the standard enthalpies, entropies and Gibbs energies of sublimation and evaporation of compounds were calculated at 298.15 K. The standard molar formation enthalpies of compounds in crystalline state at 298.15 K were determined indirectly by the corresponding standard molar combustion enthalpy, obtained using bomb calorimetry combustion.ConclusionsDetermination of the thermodynamic properties for these compounds may contribute to solving practical problems pertaining optimization processes of their synthesis, purification and application and it will also provide a more thorough insight regarding the theoretical knowledge of their nature.Graphical abstract:Generalized structural formula of investigated compounds and their formation enthalpy determination scheme in the gaseous state

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Abstract.1 The temperature dependencies of both acids solubility in acetonitrile, dimethylketone, isopropanol, ethylacetate and benzene were investigated. The results were represented by Shredder's equation according to which enthalpies, entropies and Gibbs energy of solubility at 298 K were determined. Fusion heats of the acids were determined using differential thermal analysis. In accordance with obtained values the enthalpies, entropies and Gibbs energy of mixing were calculated. The compensating effect of mixing was observed for al solvents with carboxy group.