Comparing Assignment of the Diffuse Reflectance Infrared Fourier Transform Spectra of Silver Surface Complexes with Solid Silver Compounds*

The diffuse reflectance infrared flourier transform spectroscopic technique has been applied to analyse the adsorbed surface complexes, formed in the oxidation of acetaldehyde, by comparing the DRIFT-spectra of the reaction intermediates to hose of four different solid silver compounds. Must characteristic IR bands obtained were clearly assigned on all the solid silver compounds, advantageously in the lower frequency region of IR bands compared to the traditional IR transmission technique. This comparative analysis of the spectra for the intermediates strongly suggests the existence of at least three different species. 0ne of the species can certainly be assigned to a silver acetate form. Based on the transient response data, it has been evaluated that the silver acetate form intermediate gives a surface coverage of more than θ=0.5 to 1.3 at 160℃ depending on the reaction conditions. As other possible species, a strong adsorbed acetaldehyde and an alcohol-like species are also considere