Coking, aging, and regeneration of zeolites. 13. Composition of the carbonaceous compounds responsible for the deactivation of a USHY zeolite during toluene disproportionation

Journal Article · Sun Mar 01 04:00:00 EST 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90228-A· OSTI ID:7169131

Magnoux, P; Canaff, C; Machado, F; Guisnet, M ^[1]

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1. Univ. de Poitiers (France)

The rate of formation and the composition of the carbonaceous compounds (coke) responsible for the deactivation of an ultrastable HY zeolite during toluene transformation were determined from 120 to 450 C. At low reaction temperature these compounds, consisting mainly of toluene trimers, methylanthracenes, and phenanthrenes, are the only reaction products. Being less bulky, they are retained in the zeolite pores because of their low volatility and because of their strong adsorption. At high temperature, the disproportionation of toluene is the main reaction and the coke molecules are sterically blocked in the zeolite. At 350 C pyrenic compounds are the main coke components. Located in the supercages, they limit, but do not block, the diffusion of reactant to the acid sites and that of products from the acid sites to the outer surface of the crystallites. This limitation is responsible for the activity decrease and the increase in selectivity for the smallest disproportionation products. At 450 C the coke molecules are bulkier and highly polyaromatic and deactivation is due to a blockage of the access of the reactant to the acid sites. Mechanisms are proposed to explain the formation of the various coke components.

• OSTI ID: 7169131
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 134:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
AGING
ALKYLATED AROMATICS
ANTHRACENE
AROMATICS
CARBONIZATION
CATALYTIC REFORMING
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COKE
COKING
CONDENSED AROMATICS
CRYSTAL STRUCTURE
DEACTIVATION
DECOMPOSITION
HYDROCARBONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
KINETICS
MATERIALS
MICROSTRUCTURE
MINERALS
ORGANIC COMPOUNDS
PHENANTHRENE
POROSITY
REACTION KINETICS
REFORMER PROCESSES
REGENERATION
SILICATE MINERALS
SYNTHESIS
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TOLUENE
ZEOLITES