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tert-Butylation of toluene over mordenite and cerium-modified mordenite catalysts
Ist Teil von
Applied catalysis. A, General, 2006-01, Vol.299, p.122-130
Ort / Verlag
Amsterdam: Elsevier B.V
Erscheinungsjahr
2006
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
tert-Butylation of toluene with
tert-butanol in the liquid phase was studied over large pore mordenite zeolite catalyst (H-MOR CBV 21A with Si/Al
=
10.5) and over cerium-modified parent zeolite with 1–6
wt.% of cerium. The catalytic activity and
para-selectivity of parent and cerium-modified H-mordenite catalysts is discussed. Non-modified H-MOR is catalytic active (66% conversion of toluene), with
para-selectivity near 84% at 180
°C after 8
h. Cerium modification of parent mordenite by impregnation decreases catalytic activity but enhances and retains constant high
para-selectivity (near 90%). Secondary reactions involved in the alkylation reaction are dealkylation of
tert-butyltoluenes and isomerisation of 4-
tert-butyltoluene to more stable 3-
tert-butyltoluene. The positive influence of cerium modification of parent zeolite on transformation of 4-
tert-butyltoluene was investigated. It was proved by
129Xe NMR spectroscopy that cerium/ceria is located on the external surface of H-mordenite, not inside the main channels. It was confirmed by XRD that after calcination at 500
°C in the flow of dry air cerium is in the form of cerium/ceria.
tert-Butylation of toluene with
tert-butanol over shape-selective mordenite catalysts can be an ecofriendly process for industrial preparation of 4-
tert-butyltoluene which is important intermediate product for fine chemicals.