Catalytic Transformation of Biomass-Derived Furfurals to Cyclopentanones and Their Derivatives: A Review.

Furfural (FF) and 5-(hydroxymethyl)furfural (HMF) are well-recognized biomass-derived chemical building blocks with established applications and markets for several of their derivatives. Attaining a wide spectrum of petrochemicals is the primary target of a biorefinery that employs FF and HMF as the chemical feedstock. In this regard, cyclopentanone (CPN) is a crucial petrochemical intermediate used for synthesizing a diverse range of compounds with immense commercial prospects. The hydrogenative ring rearrangement of FF to CPN in an aqueous medium under catalytic hydrogenation conditions was first reported in 2012, whereas the first report on the catalytic conversion of HMF to 3-(hydroxymethyl)cyclopentanone (HCPN) was published in 2014. Over the past decade, several investigations have been undertaken in converting FF and HMF to CPN and HCPN, respectively. The research studies aimed to improve the scalability, selectivity, environmental footprint, and cost competitiveness of the process. A blend of theoretical and experimental studies has helped to develop efficient, inexpensive, and recyclable heterogeneous catalysts that work under mild reaction conditions while providing excellent yields of CPN and HCPN. The time is ripe to consolidate the data in this area of research and analyze them rigorously in a review article. This work will assist both beginners and experts of this field in acknowledging the accomplishments to date, recognize the challenges, and strategize the way forward.