AN INFRARED SPECTROSCOPIC STUDY ON THE INFLUENCE OF WATER ON ALCOHOLS

The influence of the water content on absorption bands in FTIR spectra of monohydric alcohols was studied and the effects were compared to c hanges in spectra of absolute solvents at various temperatures. The FT IR spectra were recorded by the ATR technique in order to distinguish the weak bands of the solvents from the intensive water bands more eas ily. By addition of water to anhydrous alcohols both OH stretching and bending bands increased in intensity and width. Similar changes in sp ectra of anhydrous alcohols can be obtained by decreasing the temperat ure. Addition of water to monohydric alcohols causes the lengthening o f the intramolecular OH bonds to a smaller extent than the shortening of the intermolecular OH bonds. This contraction of the liquid structu re is also reflected in other physical and chemical properties.