Dissolving power of the binary solvent carbon tetrachloride – methanol. Solubility of caffeine: Experiment, ASL model, and MD simulation

Abstract An experimental and theoretical study of the dissolving power of the binary solvent consisting of inert (carbon tetrachloride) and self-associated (methanol) components has been carried out. According to the experimental data, the dependence of the caffeine solubility on the composition of the binary solvent has a maximum in the region of 0.5 mole fraction of the cosolvent. The maximum is also observed for the concentration dependence of the Gibbs energy of solvation calculated within the framework of molecular dynamics (MD) simulation. Within the framework of the ASL (Associated Solution + Lattice) model, it was shown that the main contribution to solubility is made by the caffeine – methanol heteroassociation. The second largest contribution is defined by non-specific intermolecular interactions in the system. A negative contribution is made by the difference in the sizes of the molecules of the mixture components.