Green synthesis of N,N′-(1,2-phenylene)bis(phthalimide-5-carboxilic acid) and the prediction of its properties: Standard enthalpies of formation and sublimation

• A novel N,N′-(1,2-phenylene)bis(phthalimide-5-carboxylic acid) was synthesized via a green method. • Supervised learning was key to analyzing bis(phthalimide) thermochemical properties. • Enthalpies of formation and sublimation were predicted using Support Vector and Kernel Ridge regressions. • Heat capacities and absolute entropies were computed using ab initio molecular methods. The synthesis of the molecule N,N′-(1,2-phenylene)bis(phthalimide-5-carboxylic acid) was carried out using green chemistry principles. The reactants 1,2-diaminobenzene and 1,2,4-benzenetricarboxylic anhydride were used for solid-state synthesis without catalysts. The resulting compound called oDIDA was characterized using infrared spectroscopy, mass spectrometry, proton nuclear magnetic resonance, and differential scanning calorimetry. Experimentally it was possible to obtain the structure, composition and melting temperature at 546.46 K. Since the compound oDIDA decomposes upon reaching its melting point, its thermochemical properties were predicted in the gaseous and crystalline phases. Ab initio molecular orbital calculations at the B3LYP/6-311++G(d,p) level of theory were occupied to determine the gaseous-phase heat capacities and absolute entropies. Supervised learning was applied to a dataset of carboxylic acids and imides to predict the standard molar enthalpies of formation and sublimation using the hold-out (70/30) evaluation technique. Finally, enthalpic increases, relative stabilities and the analysis of equilibrium reaction for the synthesis of oDIDA were obtained.