Study of the conversion of aromatic hydrocarbons on EMT-type zeolite Influence of the partial substitution of Al by Ga

Ioana Fechete (1) , Philippe Caullet (1) , Emil Dumitriu (2) , Vasile Hulea (3) , Henri Kessler (1)

1 LMM - Laboratoire de Matériaux Minéraux
2 UTI - Laboratory of Organic Chemistry
3 ICGM ICMMM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier

(Al,Ga)EMT-type zeolites (Al:Ga = 1:0, 0.75:0.25 and 0.5:0.5) were prepared and tested as catalysts in the gas-phase toluene–methanol alkylation and toluene–trimethylbenzene transalkylation. Various techniques including XRD, N2 sorption, MAS NMR and SEM were used to monitor the physico-chemical properties of these solids. The results revealed a high purity and crystallinity of the materials, and that the Ga atoms are entirely incorporated into the framework. The ammonia TPD measurements indicated that the isomorphous substitution of aluminium by gallium leads to a decrease of both acidic strength and acid sites concentration. The catalytic performances of the EMT-type solids in the conversion of methylaromatic hydrocarbons were correlated with their acid properties. Thus, the less acidic (Al,Ga)EMT samples exhibited a lower activity, but a higher selectivity towards the xylenes formation by comparison with (Al)EMT.

Mots clés: Xylene; Methanol; Alkylation; Transalkylation; (Al; Ga)EMT-type zeolite; Toluene; Trimethylbenzene

Domaines: Catalyse

Ioana Fechete, Philippe Caullet, Emil Dumitriu, Vasile Hulea, Henri Kessler. Study of the conversion of aromatic hydrocarbons on EMT-type zeolite Influence of the partial substitution of Al by Ga. Applied Catalysis A : General, 2005, 280, pp.245-254. ⟨10.1016/j.apcata.2004.11.004⟩. ⟨hal-00154836⟩