The conversion of ethanol over 3d-metal saponite-like smectites

The replacement of fossil fuel processes with renewable pathways is critical to circumvent climate change and environmental risks. A process of interest is the production of 1,3-butadiene (BD), which is primarily derived as a by-product of naphtha steam cracking. A sustainable alternative path involves converting renewable ethanol to BD via the Lebedev process, which requires a catalyst with balanced redox, acidic, and basic sites. Due to the necessity of a multifunctional catalyst, existing materials for this reaction are either compirsed of catalyst mixtures or supported catalysts. In this study, we introduce a bulk material, saponite, containing M-O-Si sites, which combine required catalytic sites for the ethanol to BD (ETB) reaction in one material. The product composition in ethanol conversion were strongly dependent on the type of 3d-metal used, while no conclusive correlation between surface properties, conversion, and product composition was observed. Herein, using V-Sap*, we achieved an ethene productivity of 448 gethene kgcat-1 h-1 (74%) at 573.15 K. High acetaldehyde productivity was maintained with Cu-Sap* (466 gAcA kgcat-1 h-1, 49%) at 573.15 K and Zn-Sap (528 gAcA kgcat-1 h-1, 55%) at 723.15 K. Mg-Sap primarily produced ethene but also yielded 10 gBD kgcat-1 h-1 BD at 723.15 K. Higher BD outputs were observed with Ni-Sap (31 gBD kgcat-1 h-1 at 523.15 K) and Mn-Sap* (51 gBD kgcat-1 h-1 at 723.15 K). This underscores the potential of saponite-based materials for flexible product outputs in ethanol conversion, influenced by the choice of integrated 3d-metal.