M. Morssli, G. Cassanas, L. Bardet
1991
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Influential Citations
6
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Journal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Abstract
Abstract The infrared and Raman spectra of sodium α-, β- and γ-hydroxybutyrates and their deuterated analogues are examined in the 4000-100 cm −1 range and an assignment of the fundamental vibrations is given. Based on the localization of the asymmetric stretching vibrations ν as OH and the out-of-plane vibration γOH, inter- and/or intramolecularly hydrogen-bonded forms are proposed: the low frequencies of ν as OH ( −1 ) and high frequencies of γOH (≈800 cm −1 ) argue in favour of the existence of intramolecular hydrogen bonding. Sodium α-hydroxybutyrate exhibits as a chelate ring with an intramolecular hydrogen bond between hydroxyl and carboxyl groups, whereas sodium, β-hydroxybutyrate has the two association forms with inter- and intramolecular hydrogen bonds. Sodium γ-hydroxybutyrate exists as a hydrogen-bonded polymer, with an intermolecular hydrogen bond between the hydroxyl groups and between the hydroxyl and carbonyl groups. At a crystallization temperature above 50°C, only the α- salt showed a structural change indicating the existence of intra- and intermolecular hydrogen bonds. This result is confirmed by differential scanning analysis.