Raman spectra of benzene adsorbed at the aqueous/silica and vapor/silica interfaces

Vapor-phase sorption of p-xylene on cobalt- and copper-exchanged SAz-1 montmorillonite

“…The loss of the P-Q-R line shape for the physisorbed species is attributed to the loss of rotational and translational freedom resulting in the formation of a liquidlike layer of p-xylene upon sorption. A shift of 4 cm"1 to lower frequency for the v19 mode is consistent with similar shifts observed in a Raman study of benzene physisorption onto silica (29). Although small in magnitude, this shift is sufficient to allow the physisorbed species to be distinguished from the vapor-phase component.…”

“…The corresponding binding energies of guest-host interactions for physisorption processes are intrinsically weak (e.g., van der Waals interactions). The strength of these interactions may or may not be sufficient to perturb the guest species sufficiently to permit discrimination of the sorbed species from that present in the bulk solution or vapor phase (29).…”

Adsorption of organic molecules on silica surface

“…The nature of sorption of nonpolar sorbates at polar solvent/ oxide interface and polar sorbates at nonpolar solvent/oxide interface were studied using Raman spectroscopy [323][324][325]. The investigation of adsorption behaviour of benzene, pyridine and azobenzene on CCl 4 /silica surface provided the evidence of strong hydrogen bonding involving benzene π-bonding electrons and silanols.…”

Aromatic–hydroxyl interaction of an alpha-aryl ether lignin model-compound on SBA-15, present at pyrolysis temperatures

“…In general, the interaction between surface hydroxyls and electron-donating adsorbates leads to a shift of the sharp free hydroxyl band to lower wavenumbers. [31][32][33][34][35] The strength of the aromatic-hydroxyl interaction with the toluene moiety is reflected in the degree of the redshift in wavenumbers of the hydroxyl infrared absorption band (discussed in Section S9 of the ESI †). 33 Similar hydroxyl redshifts have been observed when anisole and phenol molecules hydrogen bond with hydroxyls on oxide surfaces: whether through the aromatic ring, the organic molecule's oxygen, or the alcohol hydrogen.…”