Abraham Solvation Parameter Model: Examination of Possible Intramolecular Hydrogen-Bonding Using Calculated Solute Descriptors

Published solubility data for 4,5-dihydroxyanthraquinone-2-carboxylic acid dissolved in several organic solvents of varying polarity and hydrogen-bonding character are used to calculate the Abraham model solute descriptors. Calculated descriptor values suggest that engages intramolecular hydrogen formation between two phenolic hydrogens proton acceptor sites (the lone electron pairs) on neighboring quinone oxygen atom. Our study further shows existing group contribution machine learning methods provide rather poor estimates experimental-based descriptors acid, part because estimation not account likely hydrogen-bonds. The predictive aspect is illustrated by predicting 28 additional mono-solvents which experimental does exist.