Niobium grafted mesoporous silica for the production of biorenewable p-xylene from concentrated 2,5-dimethylfuran

Abstract

The Diels–Alder cycloaddition of bio-based 2,5-dimethylfuran (DMF) and ethylene and the subsequent dehydration of the cycloadduct intermediate hold promise to produce renewable p-xylene (PX) from biomass feedstocks. Developing reliable and robust catalysts for the efficient transformation of concentrated DMF to PX is highly demanded but challenging. Herein we describe an efficient approach to enable practically viable PX production from concentrated DMF (4 mol L⁻¹), employing NbO_x dispersed atomically on the interior surface of MCM-type mesoporous silica as a potent catalyst. Benefiting from its unique structural merits that lead to significant lowering of the kinetic barrier for cycloadduct intermediate formation, 8Nb/MCM exhibits excellent activity with 100% conversion and over 96% selectivity and stability (marginal activity loss after 5 cycles of reuse) toward the controlled conversion of DMF and related furanic compounds to the corresponding aromatic products using concentrated feeds. These results have important implications for the advancement of next-generation solid multifunctional catalysts by meticulously tuning the pore structure and precise location of active sites with required characteristics.