Control of Furfural Hydrogenation Selectivity Via Modified Ni-Based Catalysts Using Self-Assembled Monolayers

In a world of rising technology and limited fuel sources, the research and production of biofuels is of utmost importance. Furfural, a common component of bio-oil, is a platform chemical with the potential to create a variety of products, including an important fuel additive, methylfuran. A nickel catalyst, unlike the commonly used copper and palladium, is of interest due to its low cost despite its high reactivity and low selectivity of methylfuran. We believe that specific adsorption of furfural onto the catalyst determines its preferred reaction pathway and primary products. By adding a dense self-assembled monolayer (SAM) to the nickel catalyst surface, we can control furfural adsorption geometry, which in turn affects reaction selectivity. Experiments utilized three primary thiols: adamantanethiol (AT), octadecanethiol (C18), and 1,2-benzenedithiol (Benz). We found that benzenedithiol improved methylfuran selectivity from 10% to 88% on the pure nickel catalyst. The uncoated NiCu bimetallics decreased the selectivity of furan but did not demonstrate complete hydrodeoxygenation to methylfuran, resulting in production of furfuryl alcohol. The SAM coated bimetallics eliminated furfuryl alcohol as a product by allowing further reaction of the furfuryl alcohol to methylfuran.