Naslov
Aromatization of n-butane and 1-butene over supported Mo2C catalyst

Autori
Solymosi Frigyes, Széchenyi Aleksandar

Izvornik
Journal of Catalysis (0021-9517) 223 (2004), 1; 221-231

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Aromatization of n-butaneReaction of 1-buteneMo2C/ZSM-5Mo2C/SiO2

Sažetak
The reaction pathways of n-butane were investigated on Mo2C deposited on ZSM-5 and SiO2. Particular attention was paid to the effects of the composition of ZSM-5, to the influence of the Mo2C loading, and to the nature of supports. ZSM- 5 itself catalyzed the reaction of n-butane well above 800 K. Its efficiency sensitively depended on the composition of zeolite. Whereas the conversion of butane was ∼90% on ZSM-5 with SiO2/Al2O3=30 at 823 K, this value was only ∼24% on the sample with SiO2/Al2O3=280. The dominant reaction was the cracking of butane yielding several C1–C3 compounds. Deposition of Mo2C markedly changed the catalytic performance of ZSM-5, and the dehydrogenation and the aromatization processes came into prominence. This is particularly true in the case of less effective ZSM-5 (SiO2/Al2O3=280). From the extrapolation of selectivities to zero conversion we obtained that methane, ethane, ethylene, propylene, butene, and hydrogen are the primary products on pure and Mo2C- containing ZSM-5. Aromatics are formed in a secondary process, in the oligomerization and aromatization of butenes. The favorable effect of Mo2C is well exhibited in the case of SiO2, which was practically inactive. For 2% Mo2C/SiO2 at 823 K the selectivity of aromatics was 16–17% at a butane conversion of 26%. On this sample the main reaction was the dehydrogenation process. As the starting compound in the formation of aromatics is very likely butene, detailed measurements were performed on its reaction on the previously studied catalysts. 1-Butene exhibited a very high reactivity on pure ZSM-5 samples even at 723 K. The presence of 2% Mo2C on the zeolites resulted only in a slight change in the conversion and product selectivities. The possible mechanism of the reactions and the role of Mo2C are discussed, taking into account our surface science studies on the reaction of butyl species on a Mo2C/Mo(100) surface.

Izvorni jezik
Hrvatski

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