Structural and Textural Properties of Al/Cu- and Al/Zn-Pillared Clays for Ethanol Conversion

A montmorillonite sample was pillared using mixed solutions of Al/Cu and Al/Zn as the pillaring agent. Al/Cu- and Al/Zn-pillared clays were applied in an ethanol conversion reaction. The catalysts prepared from montmorillonite were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), 27Al nuclear magnetic resonance spectroscopy (MAS-NMR), and textural analysis by adsorption of N2. The synthesized materials showed basal spacing values around 1.6 nm for the Cu samples and 1.8 nm for the Zn samples. With the pillarization, textural properties such as specific area and micropore volume were optimized, and all samples showed an increase in micropore volume as well as a narrower pore distribution in the range of 0.77 nm. The insertion of 10% Zn in the pillaring solution produced a material with a greater amount of Al in the pentacoordinate position and also presented better results of conversion (80%) and selectivity to ethylene (81%) in the ethanol dehydration reaction.