The Hydration of Some Organic Compounds in an Aqueous Solution. I. Studies of Aliphatic Aldehydes by Raman-effect Observation

The Raman spectra of acetaldehyde, its aqueous solution and its heavy water solution have been recorded at various temperatures and in various concentrations in order to find the Raman frequencies characteristic of the hydrated species and in order to investigate the reversible hydration process. Almost all the lines have been assigned tentatively on the assumption that the hydrate molecule has Cs symmetry. The lines at 325, 480, 567, 1353, 1440, 1449, 2874, 2939 and 2996 cm−1 can be referred to as the lines characteristic of the hydrate. Supporting data have also been obtained for the related compounds for the sake of comparison. Moreover, through the intensity measurements, equilibrium constants, as well as the heat of hydration, have been evaluated as the basis for a discussion of the hydration process.