Thermodynamic parameters for the proton-transfer reaction in mannich bases

Abstract

The results of u.v. spectroscopic studies on thermodynamic parameters of the intramolecular proton-transfer (PT) reaction in Mannich bases in polar solvents are presented. It is shown that for these hydrogen-bonded systems additional phenomena such as association, self-association of ionic pairs and dissociation into ions are excluded. Determined ΔH_PT values are within the region –7 to –16 kJ mol^–1; ΔS_PT values are negative and relatively high; from –30 to –60 J K^–1. The results obtained indicate that a distinct reorganization of solvent molecules proceeds in the course of the intramolecular proton-transfer reaction.