Kinetic studies of catalytic dehydration of tert-butanol on zeolite NaH-ZSM-5

Journal Article · Mon Dec 31 23:00:00 EST 1990 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(91)90233-T· OSTI ID:5507668

Williams, C; Makarova, M A; Malysheva, L V; Paukshtis, E A; Talsi, E P; Zamaraev, K I ^[1]; Thomas, J M ^[2]

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1. Academy of Sciences Siberian Branch (USSR)
2. Davy Faraday Research Lab., London (England)

Using a combination of FTIR spectroscopy an GC kinetic methods, the authors have studied in detail the adsorption and dehydration reaction of tert-butanol (t-BuOH) on H-ZSM-5. From FTIR studies of the kinetics of t-BuOh adsorption, the authors estimate the diffusion coefficient of t-BuOH in the zeolite channels as 5 x 10{sup {minus}11}cm{sup 2}s{sup {minus}1} at 23{degree}C. The course of the dehydration reaction with time (in the temperature interval 23-60{degree}C) is followed by simultaneous growth of a peak for adsorbed water, changes in the stretching and deformation vibrations for the adsorbed organic, and changes in the nature of the H-bonded species. These changes show that dehydration is accompanied by rapid isomerization and oligomerization of the butene product (the rates of isomerization and oligomerization substantially exceed the rate of dehydration), making it impossible to identify the intermediate for the dehydration reaction (be it carbonium ion or alkoxy species). Under reaction conditions the oligomers (most likely linear C{sub 8} species) remain adsorbed on the active sites inside the zeolite channels, resulting in rapid deactivation of the sites. When the sites within the zeolite pores are completely deactivated, the dehydration reaction proceeds on sites located at the external surface of the zeolite crystallites. The latter sites are deactivated much more slowly than the former ones under these reaction conditions.

• OSTI ID: 5507668
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 127:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

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ADSORPTION
ALCOHOLS
ALKENES
BUTANOLS
BUTENES
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DEACTIVATION
DEHYDRATION
DIFFUSION
FOURIER TRANSFORMATION
GAS CHROMATOGRAPHY
HYDROCARBONS
HYDROXY COMPOUNDS
INFRARED SPECTRA
INORGANIC ION EXCHANGERS
INTEGRAL TRANSFORMATIONS
ION EXCHANGE MATERIALS
ISOMERIZATION
KINETICS
MATERIALS
MINERALS
ORGANIC COMPOUNDS
POLYMERIZATION
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SPECTRA
SPECTROSCOPY
SURFACE PROPERTIES
TRANSFORMATIONS
ZEOLITES