Analysis of the Self-Association of Aliphatic Alcohols Using Fourier Transform Infrared (FT-IR) Spectroscopy

A number of industrially important systems contain molecules, such as alcohols, that form hydrogen bonds. To correlate the thermodynamic properties of such systems, assumptions must be made in modeling the chemical equilibrium. It has been found that the data can be fit to a high degree of accuracy if it is assumed that the system contains monomers, dimers, and trimers or tetramers. Alcohols are often modeled by an infinite equilibrium model that takes into account associated species of all sizes. In this model and in others as well, an additional assumption must be made concerning the values of the various equilibrium constants; it usually is assumed that all of the equilibrium constants for a given species are equal. In this work, Fourier transform infrared (FT-IR) spectroscopy has been used to study the chemical association of aliphatic alcohols. Analysis of FT-IR spectroscopic data was used to determine the species present in a mixture and the corresponding equilibrium constants and also to evaluate t...