FT i.r. study of the silanol groups in dealuminated HY zeolites: Nature of the extraframework debris

Adsorption of benzothiophene on Y zeolites investigated by infrared spectroscopy and flow calorimetry

“…4, left), the interaction of benzothiophene with the hydroxyl species is indicated by the upward bands at about 3743, 3670, 3640 and 3580 cm À1 . The band at about 3670 cm À1 arises from the hydroxyl species attached to the extra framework aluminium species [33,34]. As mentioned above, the pore structure of the CuY degrades to some extent during autoreduction in the pre-treatment, which enhances the probability of the adsorbate molecules interacting with the protons in the sodalite cage.…”

Dealumination of HBEA zeolite by steaming and acid leaching: distribution of the various aluminic species and identification of the hydroxyl groups

“…Chemical and 29 Si NMR analysis of the NH 4 -BEA sample shows total and framework Si/Al ratios of 12.5 and 15.5, respectively.…”

Catalytically active and selective centers for production of ɛ-caprolactam through liquid phase Beckmann rearrangement over H-USY catalyst

“…The band at 3740 cm À1 is assigned to external silanol groups. However, because this band is rather broad, it may be accompanied with hydroxyls on silica-alumina debris [42]. The band at around 3690-3670 cm À1 is generally assigned to Al-OH of EFAL [20], and hydroxyls at defect sites as well [43].…”