(208d) Heterogeneous Catalysts for the Conversion of Glucose to 5-(hydroxymethyl)Furfural (HMF)

Growing environmental concerns and dwindling fossil fuel resources have increased the need for a shift toward renewable, carbon neutral resources. Biomass has been identified as a promising renewable resource. A possible avenue toward establishing generalized, biomass-based platforms for the production of fuels and chemicals is based on the catalytic conversion of biomass-based carbohydrates (i.e. fructose and glucose) to compounds that can be used directly as fuels or as gateway chemicals for the production of high value products. One such compound is 5-hydroxymethylfurfural (HMF), which effectively links the chemistry of carbohydrates with that of transportation fuels and chemicals. Our objective is to design environmentally friendly and robust heterogeneous catalysts that enable the conversion of carbohydrates to HMF. We recently reported that a Sn containing silica molecular sieve with the zeolite beta topology (Sn-Beta) can efficiently catalyze the isomerization of glucose to fructose in aqueous media even at low pH (Proc. Natl. Acad. Sci., 107 (2010) 6164). In this molecular sieve, the Sn atoms act as isolated Lewis acid centers. We will discuss our efforts to design a catalytic system, where in addition to the isomerization of glucose to fructose, the catalyst(s) also activate the dehydration of fructose to form HMF. For example, Sn-Beta (1:50 Sn:glucose) can convert a 10 wt% glucose feed to a mixture of glucose (28 wt/wt%), fructose (18) and HMF (11) in 120 minutes at 413K when HCl is added to the reaction mixture to give a pH=1 (without the Sn-Beta there is essentially no reaction). Further catalyst combinations and reaction conditions have been explored and will be reported in this presentation.