A University of Wisconsin press release, announced that university chemical and biological engineering Professor James Dumesic and his research team have developed a two-stage process for turning biomass-derived sugar, fructose, into 2,5-dimethylfuran (DMF), a liquid transportation fuel with 40 percent greater energy density than ethanol, similar to that of gasoline.
By engineering sugar through a series of steps involving hydrochoric acid and copper catalysts, salt and using butanol as a solvent, UW-Madison researchers created a path for a sustainable, carbon-neutral fuel to reduce global reliance on fossil fuels.
Not only does dimethylfuran have higher energy content than ethanol, it also addresses other ethanol shortcomings. DMF is not soluble in water and therefore cannot become contaminated by absorbing water from the atmosphere. DMF is stable in storage and, in the evaporation stage of its production, consumes one-third of the energy required to evaporate a solution of ethanol produced by fermentation for biofuel applications.
Dumesic and graduate students Yuriy Roman-Leshkov, Christopher J. Barrett and Zhen Y. Liu developed their new catalytic process, reported in the June 21 issue of the journal Nature, for creating DMF by expanding upon earlier work, previous post.
The team's method for making HMF and converting it to DMF is a two step process. Fructose is initially converted to HMF in water using an acid catalyst in the presence of a low-boiling-point solvent. The solvent extracts HMF from water and carries it to a separate location. Although other researchers had previously converted fructose to HMF, Dumesic's research group made a series of improvements that raised the HMF output and made the HMF easier to extract. For example, the team found that adding salt (NaCl) dramatically improves the extraction of HMF from the reactive water phase and helps suppress the formation of impurities.
The process converts HMF to DMF over a copper-based catalyst. The conversion removes two oxygen atoms from the compound lowering the boiling point, the temperature at which a liquid turns to gas, and making it suitable for use as transportation fuel.
Salt, while improving the production of HMF, presented an obstacle in the production of DMF. It contributed chloride ions that poisoned the conventional copper chromite catalyst. The team instead developed a copper-ruthenium catalyst providing chlorine resistance and superior performance.
The scientists say that fructose can be obtained directly from fruits and plants or made from glucose.
But more work needs to be done to assess the environmental impact of this new fuel.