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Roles of ZSM‐5 modifier agents in selective toluene disproportionation

1993; Wiley; Volume: 71; Issue: 4 Linguagem: Inglês

10.1002/cjce.5450710408

1939-019X

María A. Uguina, J.L. Sotelo, David P. Serrano,

Catalytic Processes in Materials Science

Abstract Selective toluene disproportionation has been studied over ZSM‐5 zeolites modified with P , Si and Cs compounds. For the P and Si modified samples, p ‐xylene proportion in the primary product was 100% due to the diffusional control on the internal xylene isomerization. The number and strength of the acid sites are reduced by the three modifier agents but a relationship between para‐selectivity and the decrease of the acid strength has not been observed. The most para‐selective samples have been those modified with Si which has been related to the deposition of this agent on the external surface of the zeolite crystals avoiding the primary product isomerization.