New Technique for the Characterization of Carbonaceous Compounds Responsible for Zeolite Deactivation

doi:10.1016/S0167-2991(09)60370-0

Studies in Surface Science and Catalysis

Volume 34, 1987, Pages 317-330

https://doi.org/10.1016/S0167-2991(09)60370-0 Get rights and content

Abstract

A new technique has been developed for characterizing the carbonaceous compounds deposited in zeolites, responsible for their deactivation (“coke”). The technique consists in treating the coked samples at room temperature by a solution of hydrofluoric acid at 40% in order to dissolve the zeolite and to liberate the internal “coke”. This treatment does not cause any transformation of the carbonaceous compounds as shown by the tests carried out with two reactive hydrocarbons : 1-tetradecene and 9-methylphenanthrene impregnated on an inert solid. The soluble components of “coke” extracted by an organic solvent (CH₂Cl₂ are analyzed by classical techniques : G. C., H. P. L. C., H-N. M. R., M. S… Two examples are given here to show the interest of this technique. The first concerns the effect of the reaction temperature (120-450°C) on the composition of the “coke” formed during propene transformation on a USHY zeolite; the reactional steps involved in “coke” formation were able to be defined. In the second example, the mode of deactivation of three protonic zeolites : USHY, H mordenite and HZSM5, during dimethylether conversion into hydrocarbons, was specified by using results obtained from adsorption measurements on the “coked” zeolites and from analysis of the carbonaceous compounds.

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New Technique for the Characterization of Carbonaceous Compounds Responsible for Zeolite Deactivation

J. Catal.

J. Catal.

Catal. Rev. Sci. Eng.

Ind. Eng. Chem., Process, Des. Dev.

J. Phys. Chem.

NATO Asi Series E, 54

Studies in Surface Science and Catalysis

Ind. Eng. Chem. Process Des. Dev.