Continuous catalytic process for the selective dehydration of glycerol over Cu-based mixed oxide

• Published in: Journal of catalysis Vol. 385; pp. 160 - 175
• Main Authors: Mazarío, Jaime, Concepción, Patricia, Ventura, María, Domine, Marcelo E.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-05-2020
• Subjects: Acetol; Copper catalyst; Glycerol; Glycerol dehydration; Mixed oxides; Glycerol; Glycerol dehydration; Acetol; Copper catalyst; Mixed oxides
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2020.03.010

[Display omitted]
•Cu-Mg-Al oxide catalyzes selectively glycerol dehydration to acetol in a continuous flow system.•10.0%Cu-HT-4 catalyst offers the best glycerol conversion and acetol selectivity.•Cu-catalysts remain active after several re-uses by introducing regeneration cycles.•Cu is essential for acetol production with high reaction rate and more selective than Ni or Co.•In situ spectroscopic studies evidence Cu1+ as the most active Cu species in the catalyst.
The selective dehydration of glycerol to hydroxyacetone (acetol) was studied with Cu-based mixed oxides derived from hydrotalcite as catalysts in a continuous flow fix-bed reactor. Catalysts were prepared by co-precipitation and characterized by ICP, N2 adsorption, XRD, NH3-TPD, CO2-TPD, TPR and TEM. Different parameters were investigated to develop the most appropriate material as well as to determine the function of every metallic species. The optimized Cu-Mg-AlOx offered ≈60% acetol selectivity at >90% glycerol conversion (≈80% liquid yield, up to TOS = 9 h). The catalyst could be regenerated by calcination, achieving full activity recovery after five re-cycles. “In-situ” FTIR and XPS measurements evidenced that the presence of Cu, specially the most active Cu1+ species, was essential to carry out the dehydration to acetol with high reaction rates, and to form the preferred intermediate (with CO group); although a minor contribution from Cu0 and Cu2+ species could not be discarded.