VIBRATIONAL STUDY OF DIGLYCOLIC ACID AND POTASSIUM DIGLYCOLATE SALTS

The Raman and infrared spectra of diglycolic acid and its potassium sa lts in aqueous solution were recorded from 4000 to 200 cm(-1). Vibrati onal assignments were made for all the observed wavenumbers on the bas is of isotopic wavenumber shift, depolarization ratios and group waven umber considerations and comparison with accepted assignments for cert ain vibrational modes in other similar compounds. The three compounds (the acid, the acid salt and the neutral salt) belong to the C-s symme try group, but their conformations are quite different. In the crystal line state, the acid salt has a strong hydrogen bond and appeared to b e of type A according to Speakmann's classification.