Molybdenum-Catalyzed Deoxydehydration of Diols to Olefins
Processes capable of transforming biomass into renewable substitutes for petrochemicals are in high demand. Such a process must be cost efficient, eco-friendly, and use an abundant resource. The deoxydehydration (DODH) reaction was chosen because it is a single step reaction that transforms a vicinal diol like cellulose into an alkene, which can be used to make petroleum-based materials. This reaction requires a catalyst, reductant and a solvent. The chemicals commonly used in this process are either not abundant, expensive or unsustainable. Commonly used catalysts in a deoxydehydration reaction are based on rhenium (Re); which is a rare and expensive metal and makes it an undesirable catalyst for large-scale processes. We have explored the use of a molybdenum (Mo) based catalyst, ammonium heptamolybdate (AHM), (as Mo is relatively abundant and cheap) in toluene as the solvent and using sodium sulfite (Na2SO3) as the reductant. This reaction was performed at 170 οC for 24 h, yielding the alkene in 8-32 %. Other molybdenum based heterogeneous and homogeneous catalysts were evaluated for their effectiveness.