Characterization of acid sites on γ-alumina and chlorinated γ-alumina by 31P NMR of adsorbed trimethylphosphine

• Published in: Catalysis letters Vol. 43; no. 3-4; pp. 213 - 218
• Main Authors: GUILLAUME, D, GAUTIER, S, DESPUJOL, I, ALARIO, F, BECCAT, P
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.02.1997; Springer Nature B.V
• Subjects: Acids; Alumina; Aluminum oxide; Catalysis; Catalysts: preparations and properties; Chemistry; Chlorination; Exact sciences and technology; General and physical chemistry; Lewis acid; NMR spectroscopy; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Transitional aluminas; Gas solid adsorption; Gamma form; Lewis site; Chlorination; Tertiary phosphine; Acidic site; Catalyst supports; Surface properties; Nuclear magnetic resonance spectroscopy; Bronsted site; Alumina; Modified material
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1023/A:1018955025955

31P MAS NMR of adsorbed trimethylphosphine (TMP) has been used to characterize the surface acid properties of γ-alumina and chlorinated γ-alumina. Combined with thermodesorption of TMP, NMR has allowed the determination of the strength distribution of Brønsted and Lewis acid sites on these samples. γ-alumina chlorination with 1,2-dichloropropane at 500°C first increases the numbers of ``strong'' Lewis and ``strong'' Brønsted acid sites, second decreases the number of ``weak'' Lewis acid sites. The ``strong'' sites are the ones TMP is desorbed from above 200°C and the ``weak'' sites up to 200°C.