Experimental Determination of the Standard Enthalpy of Formation of Trimellitic Acid and Its Prediction by Supervised Learning

The standard molar enthalpy of formation for trimellitic
acid (TMAc)
in the crystalline phase at 298.15 K, ΔfHm°(cr), was calculated experimentally
from the enthalpy of combustion through combustion calorimetry experiments.
Likewise, the standard molar enthalpy of sublimation was determined
from the standard molar enthalpy of fusion and from the standard molar
enthalpy of vaporization from differential scanning calorimetry and
thermogravimetry, respectively. Subsequently, the standard molar enthalpies
of formation in the gas-phase at 298.15 K, ΔfHm°(g), were calculated.
The enthalpies of formation for TMAc, hemimellitic, and trimesic acids
were predicted using multiple linear regression (MLR) with a nonreplacement
evaluation technique. MLR was applied to the data set that allowed
estimating these thermochemical properties with an R2 greater than 0.99. This model was used to compare the
predicted and experimental results for benzene carboxylic acids.