Hydrogenation of Cyclic 1,3-Diones to Their 1,3-Diols Using Heterogeneous Catalysts: Toward a Facile, Robust, Scalable, and Potentially Bio-Based Route

• Published in: ACS omega 2021-02, Vol.6 (6), p.4313-4328
• Main Authors: van Slagmaat, Christian A. M. R, Verzijl, Gerard K. M, Quaedflieg, Peter J. L. M, Alsters, Paul L, De Wildeman, Stefaan M. A
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.0c05563

Cyclopentane-1,3-diol (4b) has gained renewed attention as a potential building block for polymers and fuels because its synthesis from hemicellulose-derived 4-hydroxycyclopent-2-enone (3) was recently disclosed. However, cyclopentane-1,3-dione (4), which is a constitutional isomer of 3, possesses a higher chemical stability and can therefore afford higher carbon mass balances and higher yields of 4b in the hydrogenation reaction under more concentrated conditions. In this work, the hydrogenation of 4 into 4b over a commercial Ru/C catalyst was systematically investigated on a bench scale through kinetic studies and variation of reaction conditions. Herein, the temperature, H2-pressure, and the solvent choice were found to have significant effects on the reaction rate and suppression of undesired dehydration of 4. The cis–trans ratio of 4b is naturally generated as 7:3 in these reactions. However, at elevated reaction temperatures, 4b epimerizes, yielding more trans products. This effect was also studied and rationalized from a thermodynamic perspective using DFT. The combined optimized reaction conditions provided 78% yield for 4b, and successful applications to 8-fold scaled up reactions (40 g) and a substrate scope of several 1,3-diones demonstrate the general applicability of this catalytic approach.