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Ethylation of coking benzene over nanoscale HZSM-5 zeolites: Effects of hydrothermal treatment, calcination and La2O3 modification

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Abstract.
The objective of this work is to study some post-treatment effects, including hydrothermal treatment,
calcination and La2O3 modification, on the catalytic performance of a nanoscale HZSM-5 zeolite for
ethylation of coking benzene. The nanoscale HZSM-5 zeolite was treated by hydrothermal treatment,
calcination and La2O3 modification in series, and the prepared catalysts were evaluated in a fixed-bed
down-flow reactor. The catalyst samples were also characterized by XRD, SEM, NH3-TPD, IR, N2
adsorption–desorption isotherms, cyclohexane adsorption isotherms and TG. The results showed that
both the hydrothermal treatment and the calcination led to a drastic decrease in the total amount of acid
sites, while the subsequent La2O3 modification resulted in only a slight increase in the number of acid
sites. These post-treatments led to a decrease in the Bro¨nsted/Lewis ratio of the nanoscale HZSM-5
zeolites. The hydrothermal treatment followed by the La2O3 modification created new large micropores
on the nanoscale HZSM-5 zeolites, which results in the coexistence of micropores and large micropores.
The increase in the catalyst lifetime can be attributed to both suppression of carbon deposit formation
and partial accommodation of the formed carbon deposit in La-C-HT-HZSM-5 catalyst with lower
acidity, lower ratio of B/L and complicated pore structure. The prepared La-C-HT-HZSM-5 catalyst
showed good catalytic stability within 1500 h of time on stream in the ethylation of coking benzene
containing high sulfur content (375 ppmw) with ethylene under industrial reaction conditions.

Keywords: Coking benzene, Nanoscale HZSM-5, Hydrothermal treatment, Calcination, La2O3 modification.

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Informasi Detail

Judul Seri

Applied Catalysis A: General

No. Panggil

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Penerbit

London : Elsevier B.V.., 2009

Deskripsi Fisik

Applied Catalysis A: General 355 (2009) 184–191

Bahasa

English

ISBN/ISSN

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Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

KIMIA

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

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