IONIC EQUILIBRIA IN NEUTRAL AMPHIPROTIC SOLVENTS - RELATIONSHIPS BETWEEN ELECTROLYTE PK VALUES AND SOLVENT POLARITY AND COMPOSITION FOR SEVERAL BINARY ISOPROPYL-ALCOHOL MIXTURES

The progressive addition of cosolvent Into any particular solution of an electrolyte causes a gradual change in the dissociation constant (pK) of the electrolyte. The changes in pK values of picric acid and tetrabutylammonium picrate in isopropyl alcohol-cosolvent mixtures have been related with the dielectric constant (ϵ) and the polarity of the mixed solvent, the latter measured by means of ETN(30) Dimroth Reichardt’s parameter. Theoretical equations, which show linear relationships between these magnitudes and also with the solvent composition, have been developed and checked experimentally for solutions up to about 20% (v/v) of cosolvent. A variety of cosolvents of different polarity have been used. © 1990, American Chemical Society. All rights reserved.