The influence of the binder on the properties and performance of palladium-containing zeolite
catalysts in the n-octane hydroisomerization was studied. Three different framework zeolites
were used as catalysts: mordenite, β, and ZSM-5 with or without binder. To characterize the
catalysts, surface area measurements, temperature-programmed desorption of ammonia, atomic
absorption spectroscopy, inductively coupled plasma emission spectrophotometry, hydrogen
chemisorption, and solid-state 27Al NMR were used. Catalytic performance of the zeolites was
strongly influenced by the binder because its presence modified both zeolite acidity and porosity.
A decrease in the strong acidity of the zeolites could be observed when the samples were
agglomerated, due to a solid-state ion exchange between the zeolite protons and bentonite sodium.
The neutralization of some zeolite acid sites caused a decrease in the n-octane conversion for
mordenite (from 90.5 to 53.8 mol %) and ZSM-5 (from 78.4 to 71.2 mol %) zeolites. The binder
modified the porosity of the zeolite providing meso- and macropores, which allow a higher
formation of branched isomers for mordenite (from 27.3 to 48.9 mol %) and ZSM-5 (from 14.3 to
35.4 mol %). Activity of β zeolite was modified by the presence of extraframework aluminum
species (EFAL) formed during the agglomeration process, improving both n-octane conversion
(from 22.9 to 88.7 mol %) and branched isomer selectivity (from 48.7 to 77.5 mol %).
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