Selective Hydrogenation of HMF to DHMF Using Cationic Ru‐PNP Complex

Abstract The advancement of biorefinery technology for converting non‐edible biomass into bio‐based fuels and chemicals, like 5‐hydroxymethylfurfural (HMF), is attracting considerable attention as a sustainable substitute for fossil‐based industrial chemicals. A highly selective, efficient, and superior catalyst has been developed for the aqueous‐phase hydrogenation of 5‐hydroxymethylfurfural (HMF) to 2,5‐dihydroxymethylfuran (DHMF) under very mild reaction conditions. Thus, at 30 °C with 30 bar H 2 , 0.1 mol% of a novel cationic Ru‐PNP pincer complex salt ( Ru‐4 ) provides a quantitative yield of DHMF after 6 h. In comparison, the state‐of‐the‐art catalyst, the commercially available i Pr Ru‐MACHO, leads to merely 7% of DHMF. In fact, Ru‐4 is consistently superior to i Pr Ru‐MACHO by approximately an order of magnitude with respect to yield over a range of reaction conditions between 30–100 °C.