Calorimetric and Computational Thermochemical Study of 3,3-Tetramethyleneglutaric Acid, 3,3-Tetramethyleneglutaric Anhydride, and 3,3-Tetramethyleneglutarimide

Abstract

The standard (p(o) = 0.1 MPa) molar energies of combustion in oxygen, at T = 298.15 K, of solid 3,3-tetramethyleneglutaric acid and the related 3,3-tetramethyleneglutaric anhydride and 3,3-tetramethyleneglutarimide were measured by static bomb combustion calorimetry. The values of the standard molar enthalpies of sublimation, at T = 298.15 K, were obtained by Calvet microcalorimetry, allowing the calculation of the standard molar enthalpies of formation of the compounds, in the gaseous state, at T = 298.15 K. The geometries of the experimentally studied compounds were fully optimized using density functional theory with the B3LYP functional and extended basis sets. More accurate energies were also obtained from single-point calculations at the most stable B3LYP/6-311G** geometries, using the cc-pVTZ basis set. From these calculations the standard molar enthalpies of formation of 3,3-tetramethyleneglutaric acid, 3,3-tetramethyleneglutaric anhydride, and 3,3-tetramethyleneglutarimide were estimated using isodesmic reactions involving glutaric acid, glutaric anhydride, and glutarimide, respectively. Experimental and computational results were used in the discussion of the interrelation of energetics and structure in these compounds and compared with other structurally related compounds.

Standard molar enthalpies of formation of 3-methylglutaric and 3,3-dimethylglutaric anhydrides

“…The standard molar enthalpy of formation in gas phase at 298.15K was calculated from the standard molar enthalpy of sublimation and formation in the crystal phase at 298.15K. This value together with the one of glutaric anhydride (GA) [27], were occupied to validate the functional group contribution methods used to estimate some thermochemical properties of 3,3dimethylglutaric anhydride (DMGA), which showed drawbacks during purification and, therefore, in all its experimental analysis. Finally, a statistical method applying a multiple linear regression model based on machine learning was applied to estimate the enthalpy of formation in gas phase to DMGA.…”