Quantitative liquid-phase infrared spectra of several simple organic compounds.

Many simple compounds exhibit pronounced changes in absorptivity between the vapor and liquid phases, particularly at longer wavelengths in the infrared. Therefore liquid-phase spectral data cannot be computed from available quantitative vapor spectra. Quantitative liquid spectra are presented for methanol, ethanol, formic acid, acetic acid, acetone, and diethyl ether in the region 2.5-13 microm. While phase-transition changes in absorptivity of these compounds do not approach those of water, they can be significant, and troublesome if not appreciated.