A ring structure model of the acid centers of amorphous silica-alumina catalysts

Autor:	L. L. Murrell, N. C. Dispenziere
Rok vydání:	1989
Předmět:	Chemistry Inorganic chemistry chemistry.chemical_element Amorphous silica-alumina General Chemistry Atmospheric temperature range Ring (chemistry) Catalysis Ion law.invention chemistry.chemical_compound Crystallography Aluminium law Calcination Organometallic chemistry
Zdroj:	Catalysis Letters. 2:329-333
ISSN:	1572-879X 1011-372X
DOI:	10.1007/bf00768174
Popis:	Calcination of a 500 m2/g SiO2-Al2O3 co-gel from 350 to 875 °C leads to a constant ratio of Lewis-to-Bronsted sites over this temperature range. A model is proposed to account for this surprising result: a 3–4 member ring structure of SiO2 reacts with aluminum ions and inserts between Si groups in the ring. This expanded ring structure is proposed to be the local structure responsible for the acidity. The density of WO3 clusters formed on SiO2 of 1.2 nm size is analogous to the density of Si-Al ring structures proposed to be present on the surface of SiO2-Al2O3 solid acid catalysts.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::642944650f1d834e4995c14f184cacc0 https://doi.org/10.1007/bf00768174 Zobrazit plný text záznamu Full text from SpringerLink