n-Butanol to iso-butene in one-step over zeolite catalysts

• Published in: Applied catalysis. A, General Vol. 403; no. 1; pp. 1 - 11
• Main Authors: Zhang, Dazhi, Barri, Sami A.I., Chadwick, David
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 22-08-2011; Elsevier
• Subjects: Catalysis; Catalysts; Chemistry; Coke; Conversion; Deactivation; Dehydration; Exact sciences and technology; General and physical chemistry; Ion-exchange; iso-Butene; Isomerisation; n-Butanol; Stability; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zeolite; Zeolites; Zeolites: preparations and properties; Isomerisation; n-Butanol; Zeolite; Dehydration; iso-Butene; Diluent; Water; Coke; Alcohol; NMR spectrometry; Selectivity; Molecular sieve; Alkanol; Butene; Deactivation; Stability; Isomerization; Thermogravimetry; Water vapor; Conversion; X ray diffraction; Ammonia; Heterogeneous catalysis; Butanol; Ethylenic compound; Catalyst
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2011.05.037

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► One step conversion of
n-butanol to
iso-butene has been demonstrated. ► Medium pore size, unidirectional channel zeolites show high performance. ► The productivity of
iso-butene over Theta-1 was greater than 7.0
kg
kg
cal
h
−1. ►
n-Butanol to
iso-butene is compared to isomerisation of 1-butene with added water. ► The deactivation of ferrierite is attributed to the effect of product steam from dehydration.
The conversion of
n-butanol to
iso-butene in one-step has been studied over zeolite catalysts (Theta-1, ZSM-2, Ferrierite, ZSM-5, SAPO-11 and Y). The zeolites were characterized by XRF, XRD, BET, and NH
3-TPD. Coke formation on the spent catalysts was measured by TGA. The unidirectional channel zeolites Theta-1 and ZSM-23 gave high yields of
iso-butene and showed high stability. In contrast, ferrierite, although initially active, deactivated due to the presence of water from dehydration giving progressively lower yields of
iso-butene. ZSM-5 showed high activity but low selectivity to
iso-butene; SAPO-11 was structurally unstable under the reaction conditions. Ferrierite deactivation was studied in more detail by NH
3-TPD,
27Al MAS NMR and by a comparison of 1-butene isomerisation with and without the presence of added steam. A similar comparison was made for ZSM-23 and Theta-1 which further emphasised their stability and showed that for these catalysts under the reaction conditions used, the product steam from
n-butanol dehydration promoted
iso-butene yield by acting as a diluent.