Effective diffusivities in zeolites. 2. Experimental appraisal of effective shape-selective diffusivity in ZSM-5 catalysis

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1241· OSTI ID:5602306

Garcia, S F; Weisz, P B ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States)

A method is described for experimentally probing the molecular shape-sensitive diffusivity of a molecular species effective during the steady-state process of catalysis in a zeolite. It does not require the use of catalyst samples of differing and known particle (i.e., crystallite) sizes but with otherwise identical properties. It can be carried out on a single catalyst sample. The method makes use of hydrogen-deuterium transfer as the catalytic reaction. Instead of comparing reaction rates on different crystallite sizes, it makes use of altering the magnitude of a pseudo-first-order reaction rate constant to probe for the effect of diffusion inhibition. The method is used here to examine the magnitude of the catalytically effective diffusivity of ortho-xylene is ZSM-5, in comparison to the [open quotes]uptake diffusivity[close quotes] derived from sorption measurements. 8 refs., 6 figs.

• OSTI ID: 5602306
• Journal Information: Journal of Catalysis; (United States), Vol. 142:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
XYLENES
DIFFUSION
ZEOLITES
SORPTIVE PROPERTIES
CATALYSTS
CHEMICAL REACTION KINETICS
DEUTERIUM
HETEROGENEOUS CATALYSIS
HYDROGEN
INHIBITION
ISOTOPIC EXCHANGE
SORPTION
ALKYLATED AROMATICS
AROMATICS
CATALYSIS
ELEMENTS
HYDROCARBONS
HYDROGEN ISOTOPES
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISOTOPES
KINETICS
LIGHT NUCLEI
MATERIALS
MINERALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
REACTION KINETICS
SILICATE MINERALS
STABLE ISOTOPES
SURFACE PROPERTIES
400201* - Chemical & Physicochemical Properties