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Synthesis and characterization of zeolites ZSM-5 from acid-activated kaolinite clay

Abstract:

Zeolites ZSM-5 were synthesized using a acid treated natural kaolin as silicon/aluminum source at different acid/cay mass ratio and tetrapropylammonium bromide as synthesis director agent. The catalytic activity was measured by the dehydration reaction of 1-dodecanol. By XRD diffraction patterns with sharp and intense reflections in the expected range were observed, suggesting a high crystallinity without the evidence of kaolin signals. The synthesized zeolites showed specific areas higher than 300 m2/g and type I adsorption isotherms, characteristic of microporous materials. By SEM it was confirmed that the solids had particles with cubic morphology bigger than 10 μm and other smaller with irregular morphology, while by TEM it was appreciated the presence of a porous structure in the micro range. The catalysts were highly active for dehydration reaction of 1- dodecanol being the ZSM-5(0,40) material the most active one with a 100% conversion.