Detection and identification of a methanol-water complex by factor analysis of infrared spectra

摘要

Fourier transform infrared absorption spectra, between 1850 and 2700 cm(-1), were used to study the intermolecular interactions between methanol and water. Digitized spectra obtained from methanol-water mixtures, with methanol mole fraction varying from 0 to 1.00, were subjected to factor analysis. Principal factor analysis indicated that three chemical factors were responsible for the data. Window factor analysis, a model-free method, was used to extract the concentration profiles of three species, which were identified as water, methanol, and a methanol-water complex. The profiles were used to deduce the stoichiometry of the complex, which was found to consist of one molecule of methanol and two molecules of water. The dissociation constant of the complex was determined to be 306 +/- 33 M-2. These results differ from those reported by other investigators. [References: 21]