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Titolo:
ADAPTATION OF AL-27 CP MAS NMR TO THE INVESTIGATION OF THE ADSORPTIONOF MOLYBDATE IONS AT THE GAMMA-AL2O3/WATER INTERFACE/
Autore:
DEWILMAR DM; CLAUSE O; DELACAILLERIE JBD;
Indirizzi:
ECOLE SUPER PHYS & CHIM IND VILLE PARIS,PHYS QUANT LAB,URA CNRS 1428,10 RUE VAUQUELIN F-75321 PARIS 05 FRANCE ECOLE SUPER PHYS & CHIM IND VILLE PARIS,PHYS QUANT LAB,URA CNRS 1428 F-75321 PARIS 05 FRANCE INST FRANCAIS PETR,KINET & CATALYSIS DIV F-92852 RUEIL MALMAISON FRANCE
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 36, volume: 102, anno: 1998,
pagine: 7023 - 7027
SICI:
1089-5647(1998)102:36<7023:AOACMN>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYDROTREATING CATALYST PRECURSORS; INTEGER QUADRUPOLAR NUCLEI; HYDRODESULFURIZATION CATALYSTS; AQUEOUS-SOLUTION; GAMMA-ALUMINA; SPIN LOCKING; IMPREGNATION; RESONANCE; FRESH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
22
Recensione:
Indirizzi per estratti:
Citazione:
D.M. Dewilmar et al., "ADAPTATION OF AL-27 CP MAS NMR TO THE INVESTIGATION OF THE ADSORPTIONOF MOLYBDATE IONS AT THE GAMMA-AL2O3/WATER INTERFACE/", JOURNAL OF PHYSICAL CHEMISTRY B, 102(36), 1998, pp. 7023-7027

Abstract

Recent studies have demonstrated the importance of the formation of ahydrated aluminum polymolybdate when a catalyst is prepared by impregnating gamma-alumina with an aqueous solution of ammonium heptamolybdate [Carrier, X.; Lambert, J. F.; Che, M. J. Am. Chem. Sec. 1997, 119, 9, 10137-10146]. We show here how a simple (H-1) Al-27 CP MAS NMR experiment performed in the intermediate regime can easily reveal the formation of a hydrated aluminum polymolybdate on the surface of alumina. Taking, simultaneously, advantage of the differences in dipolar polarization transfer and those in quadrupolar effects on spin-locking efficiency, it is possible, after setting the experimental parameters on reference compounds, to partially suppress the signal resulting from thealumina support at 8.5 ppm while enhancing the 14 ppm resonance of the aluminum polymolybdate. In this way, the occurrence of a hydrated polymolybdate is evidenced, not only on samples impregnated with (NH4)(6)Mo7O24 but also with Na2MoO4. Furthermore, a dialysis experiment proved that a dissolution/reprecipitation mechanism is at least in part responsible for the formation of the AI-O-Mo bond.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 10:55:46