Infrared spectra and hydrogen bonding of monoalkali salts of malonic acid and their dialkyl derivatives

Abstract

Infrared spectra of monoalkali salts of malonic acid showed that the strong inter-molecular hydrogen bonding in these salts varied from an unsymmetric type in Li and Na salts to a symmetric type in the K, Rb and Cs salts. In the monopotassium salts of dialkyl malonic acids, strong symmetric intra molecular hydrogen bonds were found in the diethyl and di n-propyl derivatives (but not in dimethyl) which inhibits the dissociation of the second carboxylic group and explains the large K₁/K₂ values observed in water.