Some Comments on the Infrared Spectra of Vapors

Abstract

The bands in ir vapor spectra shift from their frequency positions in liquid, solution, or solid spectra according to the extent of the interaction of the sample with the solvent or other solute or condensed molecules. The most noticeable differences occur with hydrogen bonding compounds, where the vapor spectra are analogous to the spectra of very dilute solutions and can be correlated with the presence of free monomers, particularly at higher vapor temperatures. The spectra of alcohols, phenols, acids, amines, and amides have been obtained at temperatures ranging from 80°–190°C. The frequencies of the typical bands are tabulated. The carbonyl band frequencies of a selection of carbonyl compounds are also tabulated.