TOWARD A SOLVENT BASICITY SCALE - THE CALORIMETRY OF THE PYRROLE PROBE

The solution calorimetry of pyrrole, A-methylpyrrole, benzene, and toluene in 35 solvents has been investigated. The results obtained with an appropriate combination of the solvation enthalpies of these four compounds, used as probes, suggest a new hydrogen-bond basicity scale for solvents. The results have been tested against previously suggested scales. The “pure solvent method” proposed in this paper yields accurate basicity estimations for the 35 solvents tested. An additional practical advantage of this method is that ∆H0sol can beaccurately and easily measured. © 1990, American Chemical Society. All rights reserved.