Direct conversion of cellulose to HMF demonstrated

Researchers at Pacific Northwest National Laboratory (PNNL; Richland, Wash.; www.pln.gov) have published the first direct route for converting plant cellulose to 5-hydroxymethylfurfural (HMF), a valuable platform chemical for the production of both plastics and biofuels. Appearing in the June issue of Appl. Cat. A, the research could mark a pathway to less expensive, large-scale production of HMF. Although a two-step process of HMF formation from plant biomass via simple sugars has been demonstrated previously, a mild-temperature, single-step process to convert cellulose directly to HMF has remained elusive. PNNLs conversion process relies on the use of twin metal chlorides (CuCl2 and CrCl2) dissolved in an ionic liquid (1-ethyl-3-methylimidazolium chloride) at temperatures of 80 to 120°C to catalyze the single-step conversion of cellulose to HMF. In the laboratory, the process achieves an unrefined purity of 96% among recoverable products, and an overall HMF yield of about 55%. Principal investigator Conrad Zhang, who has since left PNNL, says that cellulose depolymerization occurs at a rate one order of magnitude faster than conventional acid-catalyzed hydrolysis. The research group evaluated a wide range of metal chlorides and…