Strong acidity of silanol groups of zeolite beta: Evidence from the studies by IR spectroscopy of adsorbed CO and 1H MAS NMR

Template-free synthesis of high degree crystallinity zeolite Y with micro–meso–macroporous structure

“…The shoulder at 3735 cm À1 corresponded to internal or defect silanol OH groups typical for zeolites, which are located in the close vicinity to the lattice imperfection or Lewis acid site (e.g., tricoordinated Al atom, Si-OH/Al 3+ groups). 57 The HY-mmm(60) zeolite sample synthesis led to the signicant decrease in the signals of bridging OH-groups and to the small decrease in the peak intensity of Si-OH species in the IR spectrum (Fig. 6b).…”

Practical Application of Hierarchical Beta Zeolite in a Vacuum Gas Oil Hydrocracking Catalyst

“…The relative amounts of Brønsted and Lewis acid sites of microporous Beta zeolite and hierarchical Beta zeolites are based on the pyridine adsorption from the bands at 1545 and 1454 cm −1 of the infrared spectra , ; the results are summarized in Tab. .…”

Silicalite‐1 Encapsulated Fe Particles over an In‐situ Crystal Process for Syngas to Gasoline with Low CO2Selectivity

“…This high gasoline range selectivity was also attributed by prolonged crystallization period, inhere we observed a high gasoline selectivity of 66.0% for Fe@S1‐72 h, 61.7 and 55.8% for Fe@S1‐24 h and 48 h respectively. The acidic nature of isolated silanol is contemplated to be so much weak to participate in hydrocracking of hydrocarbons, however since silicalite‐1 occupies a free Al framework, the hydrogen‐bonded silanol groups inside silicalite‐1 framework are accountable for weak Brønsted acid sites capable of contributing in hydrocracking . It can be noted that Fe/SiO 2 +S1‐mix had a high selectivity (59.9%) for light hydrocarbon chains (C 2‐4 ) as it occupied weak Brønsted ideal hydrocracking.…”