(266f) Minimizing Humin Formation Via HMF Derivatization

5-Hydroxymethylfurfural (HMF) is a valuable intermediate towards levulinic acid and 2,5-furandicarboxylic acid, which are both included on the list of DOE’s top 12 value-added chemicals. However, like most biomass transformations, diminished yield due to humin formation is a huge challenge. Here, we present a route that utilizes alumina-based catalysts that minimizes humin formation from HMF via acetalization and etherification of the HMF before conversion to methyl levulinate. These catalysts contain vanishingly small amounts of metals (Ti or Si) grafted from the tetrahalide that moderate the reactivity of the Al₂O₃ support. Results have shown that these Al₂O₃ based catalysts are effective in converting HMF into 2-(dimethoxymethyl)-5-(methoxymethyl)furan in nearly quantitative yield, a form we show is resistant toward humin formation and cleanly converts to methyl levulinate. Somewhat surprisingly, the derivatized HMF has very infrequently been reported in the open literature. The catalysts are synthesized from commercially available alumina and are characterized using nitrogen physisorption, TEM, DRUV-vis, TGA, and NMR. Derivatization of HMF and formation of the levulinate is carried out in methanol at 140-160C using sealed, glass batch reactors. Products are analyzed using GC-MS