Abstract
Brønsted acid sites of similar strength to those in zeolites are found in ASAs prepared by cogelation, as shown by thermogravimetric study of the dehydration of ethanol to ethylene. ASAs prepared by grafting and a commercial ASA (Siralox 30) show Brønsted acid sites that differ from those of zeolites. CO respectively ethanol adsorption followed by infrared spectroscopy identified the OH stretching frequency of the Brønsted acid sites specific to Si/Al2O3 and Al/SiO2 materials obtained by grafting to be ca. 3600cm−1 and 3640cm−1, respectively, although the intensity of the corresponding band is weak. These sites, contrary to those of a H-USY zeolite with very few extra-framework aluminum, are highly sensitive to the surface hydration state: Their number decreases with increasing temperature. The surface structure of Siralox 30 resembles that of Si/Al2O3 prepared in anhydrous conditions, showing similar isosurface acidic properties and distribution of silicon species.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
