Infrared study of the adsorption of benzene and acetonitrile on silica—alumina gels: Acidity properties and surface heterogeneity

Adsorption of Gossypol from Cottonseed Oil on Oxides

“…analysis of adsorbed species by spectroscopic methods (infrared, XPS). Protonic acid sites of moderate strength are present at the surface of calcined aluminas and silicas; in addition, weak protonic sites are present on alumina surfaces (38,39). Basic sites are present on alumina but not on silica surfaces (40)(41)(42).…”

Nature and Estimation of Functional Groups on Solid Surfaces

“…As mentioned previously (page 60), armorphous silica-aluminas did only show the typical sharp silanol band at 3750 cm -1 and acidity determinations gave a pKa value which was close to 7, identical with that reported for pure silica [134,179,182], although the catalytic properties of these materials would suggest a much higher protonic acidity. Semples and Rouxhet [183], using benzene and acetonitrile as probe molecules could demonstrate that the sharp band at 3750 cm-1 of isolated OH-groups on the surface of silica-alumina must indeed contain contributions from at least two different types of OH-groups. On interaction with both benzene or acetonitrile, two broad bands develop at 3640 and 3440 cm -1, or 3520 and 3200 cm -1, respectively, a.s shown in Figure 15.…”

IR Spectra of Some Aliphatic Nitriles Adsorbed at Liquid–Solid Interface under Pressures up to 300 MPa

“…This assignment was consistent with the reports that the peak shifted to the higher frequency side by 20-100 further information for the assignment. In this case, two IR peaks also appeared in the positions similar to the liquid/ cm 01 when acetonitrile strongly adsorbed on a Lewis site (15,16). Since peak 2 of the solid/liquid interface is broad solid system, although the intensity ratio was different, i.e., peak 2 was stronger than peak 1.…”