Relevant thermochemical data of γ-butyrolactone
(GBL), a compound of considerable industrial and environmental significance,
obtained from experimental and computational studies are reported
in this work. The standard (p° = 0.1 MPa) molar
enthalpy of formation, at T = 298.15 K, in the gaseous
phase, was determined from the enthalpy of combustion and vaporization,
obtained by static bomb calorimetry in oxygen and by Calvet microcalorimetry,
respectively. The enthalpy of formation in the gaseous phase was also
determined from G3 calculations. The excellent agreement between the
experimental and computational thermochemical data provided a critical
literature review of GBL and the proposal of new reference values
for this lactone.
The thermochemical study of the 1,3-bis(N-carbazolyl)benzene (NCB) and 1,4-bis(diphenylamino)benzene (DAB) involved the combination of combustion calorimetric (CC) and thermogravimetric techniques. The molar heat capacities over the temperature range of (274.15 to 332.15) K, as well as the melting temperatures and enthalpies of fusion were measured for both compounds by differential scanning calorimetry (DSC). The standard molar enthalpies of formation in the crystalline phase were calculated from the values of combustion energy, which in turn were measured using a semi-micro combustion calorimeter. From the thermogravimetric analysis (TGA), the rate of mass loss as a function of the temperature was measured, which was then correlated with Langmuir’s equation to derive the vaporization enthalpies for both compounds. From the combination of experimental thermodynamic parameters, it was possible to derive the enthalpy of formation in the gaseous state of each of the title compounds. This parameter was also estimated from computational studies using the G3MP2B3 composite method. To prove the identity of the compounds, the 1H and 13C spectra were determined by nuclear magnetic resonance (NMR), and the Raman spectra of the study compounds of this work were obtained.
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