Catalytically efficient Co-CoOx-Al2O3 interface for mild temperature fatty alcohol production via fatty acid transfer hydrogenation

Abstract

The cost-effective and environmentally friendly conversion of biomass to value-added chemicals under mild conditions is highly desirable but challenging. Herein, two-dimensional Co-Al hydrotalcite catalysts (CoAl-LDOx) were fabricated for selective catalytic transfer hydrogenation (CTH) of fatty acids to fatty alcohols with isopropanol (2-PrOH) as hydrogen donor. The structure and morphology of surface Co species can be regulated via reduction temperature. The optimal CoAl-LDO600 with high Co dispersion, modest reducibility, and rich Co-CoOx-Al2O3 interface achieved the highest octadecanol yield (94.2%) at full oleic acid conversion under 200 °C for 3 h. This catalyst was magnetically separable, highly stable and versatile for various fatty acids to achieve 89.1–96.7% alcohol yields. Controlled experiments suggest that 2-PrOH dehydrogenation was not highly dependent on Co structure, while the interfacial synergy of metallic Co and oxidized Co boosted the active hydrogen transfer, thus accelerating the overall reaction. The present work provided a boosted and stable catalytic system for biomass-related hydrogenation reactions without any external hydrogen supply.