Vapor Phase Conversion of Furfural to Valuable Biofuel and Chemicals Over Alumina-Supported Catalysts: Screening Catalysts

Abstract

The main focus of this study was to exploit commercial alumina-supported catalysts for the efficient conversion of lignocellulosic-derived furfural (model compound) to value-added biofuels and chemicals. In this regard, a wide range of the catalysts including noble and non-noble metals were investigated. In a fixed-bed microreactor, vapor phase catalytic conversions were conducted in the presence of hydrogen at 225 °C and ambient pressure. In terms of reaction pathways and final product, various characteristics was observed from different catalysts, among which CoMo/Al2O3 had the highest conformity in terms of 100% selectivity toward formation of 2-methyl furan (2-MF) as the final preferred product. The decision-making criteria for catalysts’ capability were not only their conversion ability but also the reaction path. Accordingly, although the catalysts (PdAg, Ni (1), Pt and RePt (1)) showed relatively higher conversions, the reaction path demonstrated sharp affinity to decarbonylation route. In contrast, the catalysts containing Co and Mo demonstrated the best performance for the hydrodeoxygenation (HDO) of furfural to 2-MF without any side reactions. Of course, different combinations of Co and Mo ratio had a decisive role in the conversion and selectivity; while selectivity was 100% with conversion of 27.8% for CoMo (2) (3.4 wt% Co and 13.6 wt% Mo), the selectivity of 79.5% and conversion of 47.1% were for CoMo (1) (4.4 wt% Co and 7.5 wt% Mo). Finally, it seems that through optimization, it is possible to choose the appropriate catalyst from the existing and conventional ones, which depends on our goal of conversion.