Study of acid–base properties of supported heteropoly acids in the reactions of secondary alcohols dehydration

• HPAs supported were used as catalysts and evaluated in reaction of dehydration of secondary alcohols.
• Catalysts were studied by a combination of Raman, XPS and XRD.
• Olefins and ethers were mainly obtained.
• Acetone and MIBK were obtained on MoP-Z, but not on the other supported HPAs.

The dehydration of secondary alcohols (propan-2-ol and 4-methylpentan-2-ol) was catalyzed by heteropolyacids (HPAs) supported on different solids. Catalysts prepared with 20 wt.% of HPAs were calcined at 400 °C and characterized by X-ray diffraction, Raman spectroscopy, XPS and N2 adsorption measurements. Stability of the Keggin structure of supported HPAs and changes in textural properties of catalysts were analyzed. The catalytic conversion of alcohols to olefins and ethers has been studied over the catalysts prepared. All catalysts presented activity in the reactions, but only molybdophosphoric acid supported on ZrO2 (MoP-Z) showed selectivity in the formation of acetone and methyl isobutyl-ketone (MIBK). Catalysts with tungstosilicic acid (WSi) and Tungstophosphoric acid (WP) were active in the formation to DIPE. The acid–base properties of the catalysts play a key role in route of the reaction mechanism.