Solubility and preferential solvation of acetaminophen in methanol plus water mixtures at 298.15 K

Abstract

The equilibrium solubility of acetaminophen in methanol + water binary mixtures at 298.15K was determined and correlated with the Jouyban-Acree model. Preferential solvation parameters by methanol (x(1,3)) were derived from their thermodynamic solution properties by means of the inverse Kirkwood-Buff integrals method. x(1,3) values are negative in water-rich mixtures but positive in compositions from 0.32 in mole fraction of methanol to pure methanol. It is conjecturable that in the former case, the hydrophobic hydration around non-polar groups plays a relevant role in the solvation. The higher solvation by methanol in mixtures of similar cosolvent compositions and methanol-rich mixtures could be explained in terms of the higher basic behavior of this cosolvent.