Palladium catalyzed hydrogenation of biomass derived halogenated furfurals†
The formation of valuable products and especially fuel candidates from lignocellulosic biomass is highly desirable. Lignocellulose derived halogenated furfurals formation was reported as highly efficient in comparison to the current existing methods of lignocellulose transformation. However, halogenated furfurals are platform chemicals and not end use chemicals, certainly not for fuels. Therefore, transformation methods of halogenated furfurals into fuels, fuels additives, or other valuable compounds are desirable. In this work we present the hydrogenation of halogenated furfurals over carbon supported palladium catalysts. Palladium catalysts showed better performance in the formation of 5-methyl furfural (MF) from halogenated furfurals compared to other catalysts. The reaction products were identified using GC-MS, FT-IR and NMR, and they were quantified using GC analysis. Catalysts were characterized with SEM, BET and pH meter. The role of catalysts properties and reaction parameters in MF preparation, and their effect on MF yields and selectivity were examined. In addition, the catalysts recovery and reuse in subsequent cycles was examined together with the recovery of hydrochloric acid or hydrobromic acid, formed as by products in halogenated furfurals hydrogenation.