The adsorption of fluorobenzene (C6H5F) and hexafluorobenzene (C6F6) onto the surface of neutral alumina is investigated by reflectance IR spectroscopy, near-IR spectroscopy, and measurement of 19F NMR chemical shift values. Chemical shifts are dependent on surface coverage and reveal multiple peaks where different adsorption environments occur. C6H5F appears to be adsorbed through polar interactions with surface hydroxyls, whereas C 6F6 shows separate resonances for the first layer of coverage and outer layers. Available surface areas are estimated, and reorientation of adsorbed hexafluorobenzene is proposed to account for chemical shift behavior and differences between calculated and measured monolayer coverage.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Colloid and Surface Chemistry