Desproporcionamento de tolueno sobre zeólitas tipo mordenita - atividade e seletividade na obtenção de xilenos

AUTOR(ES)

Escobar, Flávia A. Malacrida, Batista, Marcelo da Silva, Urquieta-González, Ernesto A.

FONTE

Química Nova

DATA DE PUBLICAÇÃO

2000-06

RESUMO

A sodium mordenite zeolite (Na-MOR) was synthesized and modified by dealumination with chloridric acid solution (H-MOR). X-Ray Diffraction (XRD), Inductive Coupled Plasm (ICP) and Scanning Electron Micrograph (SEM) techniques were used for sample characterization. The zeolite catalytic behavior was evaluated through toluene disproportionation at 435°C. It was verified that mordenites were very selective for the disproportionation reaction and the samples with higher aluminum content showed larger initial activity, however, these samples showed too a higher deactivation velocity due to a blockage of the unidimensional porous system of the zeolite by coke deposits. The selectivity to xylene isomers was practically not influenced by the Si/Al ratio and changed with the time on stream, due to coke formation. Transition state shape selectivity inside the mordenite pores is also discussed.

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