INVESTIGATION OF MMT ADSORPTION ON SOILS BY DIFFUSE-REFLECTANCE INFRARED-SPECTROSCOPY (DRIFTS) AND HEADSPACE ANALYSIS GAS-PHASE INFRARED-SPECTROSCOPY (HAGIS)

Diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) a nd headspace analysis gas-phase infrared spectroscopy (HAGIS) were use d to investigate interactions between soils and the gasoline additive methylcyclopentadienylmanganese tricarbonyl (MMT), Various soil sample s, as well as alumina and silica substrates, were studied, Each substr ate exhibited a splitting or broadening of the degenerate e nu(CO) ban d of MMT, suggesting an interaction involving one or two of the CO lig ands, The adsorption was shown to be reversible under relatively mild conditions using HAGIS, The proposed interaction is of the Bronsted ty pe, involving the carbonyl oxygen and a surface-bound water or hydroxy l group, This type of interaction could stabilize MMT by inhibiting ph otoejection of CO ligands, a common first step in the decomposition of organometallic carbonyl compounds such as MMT. (C) 1998 John Wiley & Sons, Ltd.