Hydrogen Bonding in some Adducts of Oxygen Bases with Acids: Part 7.—Thermodynamic Study by Infra-red Spectroscopy of the Association of Chloroacetic Acids with Some Oxygen Bases

Abstract

The association between the chloroacetic acids (mono-, di-, and tri-) and a scries of bases (dimethyl, dibenzyl, diphenyl sulphoxide, triphenylphosphine oxide, diphenyl selenoxide) in carbon tetrachloride was studied using the absorbance of the OH stretching band of the free acid. ATas, AG°, AH° and AS° of association were derived from the spectrophotometric data. A linear relationship between A7/° and the pKa of the acids was found. The thermodynamic quantities reflect also the basicity of the proton acceptors but not in a simple relation. The strongest hydrogen bond is formed between trichloroacetic acid and diphenyl selenoxide, — \H° being ~67 kJ/mol.