title: Mechanistic insights into the decomposition of fructose to hydroxy methyl furfural in neutral and acidic environments using high-level quantum chemical methods.
abstract: Efficient catalytic chemical transformation of fructose to hydroxy methyl furfural (HMF) is one of the key steps for attaining industrial level conversion of biomass to useful chemicals. We report an investigation of the reaction mechanisms for the decomposition of fructose to HMF in both neutral and acidic environments at the Gaussian-4 level of theory including calculation of enthalpies, free energies, and effective solvation interactions. In neutral water solvent, the transformation of fructose to HMF involves a four step reaction sequence with four transition states. The effective activation energy relative to fructose in neutral water at 298 K is very large, about 74 kcal/mol, so that transformation in neutral media around this temperature is unlikely. In contrast, the computed potential energy surface is much more favorable for the transformation in acidic media at 498 K, as the effective activation barrier is about 39 kcal/mol. The transformation in acidic media is a much more complex mechanism involving dehydration and hydrogen transfer steps, which are more favorable when protonated intermediates are involved.
authors: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States. assary@anl.gov
authors: Rajeev S
authors: RS
authors: Assary
authors: Paul C
authors: PC
authors: Redfern
authors: Jeffrey
authors: J
authors: Greeley
authors: Larry A
authors: LA
authors: Curtiss
mesh_terms: D000143:Acids / Q000737:chemistry; D005632:Fructose / Q000737:chemistry*; D005662:Furaldehyde / Q000031:analogs & derivatives* / Q000737:chemistry; D011789:Quantum Theory; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D000143:Acids; D014867:Water; D005632:Fructose; C008046:5-hydroxymethylfurfural; D005662:Furaldehyde