Production of a Renewable Functionalized 1,3-Diene from Furfural–Acetone Adduct over Supported Heteropolyacid Catalysts

The transformation of renewable feedstocks into high-value chemicals is a sustainable and eco-friendly energy technology. In this work, a functionalized 1,3-diene (1-(2-furyl)-1,3-butadiene, F-diene), with significant importance in high-performance elastomer production, was produced from a furfural–acetone adduct. Heteropolyacids were developed as efficient and eco-friendly catalysts, and a 96% selectivity toward F-diene was obtained. The relationship between catalyst structure and catalytic efficiency (conversion, selectivity, and formation rate) suggests that F-diene production is dependent on both the Keggin structure and the acidity (the amount of Brønsted and Lewis acids) of the catalysts. Linear fitting of the F-diene formation rate and acidity indicates that the catalytic capacity enhancement is linearly correlated with the amount of Brønsted acid sites, and the importance of Lewis acids is also deduced. Finally, Ce species was employed to improve the initial activity of the catalysts and yielded 93% selectivity toward F-diene after 5 h on stream. Thus, a synergistic effect between Brønsted and Lewis acids on this reaction was revealed, especially in the initial stage of the reaction.