UW-Madison: New Process Makes Diesel Fuel, Industrial Chemicals from Simple Sugar

MADISON – The soaring prices of oil and natural gas have sparked a race to make
transportation fuels from plant matter instead of petroleum. Both biodiesel and
gasoline containing ethanol are starting to make an impact on the market.

But the oil price hike has also fueled a race to find new sources for chemical
intermediates – compounds that are the raw material for many modern plastics, drugs
and fuels. Behind the scenes, American industry uses millions of tons of chemical
intermediates, which are largely sourced from petroleum or natural gas.

James Dumesic, a University of Wisconsin-Madison chemical and biological engineering
professor, reports in the June 30 issue of the journal Science on a better way to
make a chemical intermediate called HMF (hydroxymethylfurfural) from fructose: fruit
sugar. HMF can be converted into plastics, diesel-fuel additive, or even diesel fuel
itself, but is seldom used because it is costly to make.

The new process goes beyond making fuel from plants to make industrial chemicals
from plants. “Trying to understand how to use catalytic processes to make chemicals
and fuel from biomass is a growing area,” says Dumesic, who directed the HMF
research. “Instead of using the ancient solar energy locked up in fossil fuels, we
are trying to take advantage of the carbon dioxide and modern solar energy that crop
plants pick up.”

The new, patent-pending method for making HMF is a balancing act of chemistry,
pressure, temperature and reactor design. After a catalyst converts fructose into
HMF, the HMF moves to a solvent that carries it to a separate location, where the
HMF is extracted. Although other researchers had previously converted fructose into
HMF, Dumesic’s research group made a series of improvements that raised the HMF
output, and also made the HMF easier to extract.

Once made, HMF is fairly easy to convert into plastics or diesel fuel. Although the
biodiesel that has made headlines lately is made from a fat (even used cooking oil),
not a sugar, both processes have similar environmental and economic benefits,
Dumesic says. Instead of buying petroleum from abroad, the raw material would come
from domestic agriculture. Expanding the source of raw material should also depress
the price of petroleum.

Using biomass – waste products of agriculture and forestry – can also cut global
warming caused by carbon dioxide emissions from fossil fuels, says graduate student
Yuriy Roman-Leshkov, first author on the Science paper. “The nice thing about using
biomass as a replacement for all these petroleum products is that it is
greenhouse-neutral,” he says. Although burning and otherwise using fossil fuels
moves an enormous amount of carbon from the Earth into the atmosphere, the carbon
released when a biofuel burns is eventually taken up by growing plants. “This
process is really important,” Roman-Leshkov says, “because it does not introduce
additional carbon dioxide into the atmosphere.”

Juben N. Chheda, a second graduate student working on the HMF project, sees the work
as part of an explosion of interest in finding alternative sources for
petroleum-based chemicals. “We need to develop new process technologies, and HMF is
a building block that can replace products like PET, a plastic used for soda
bottles,” he notes. “This is a first step for a range of chemical products that can
be obtained from biomass resources, replacing those that come from petroleum

Dumesic is also exploring methods to convert other sugars and even more complex
carbohydrates into HMF and other chemical intermediates. “Solar energy and biology
created the stored hydrocarbons in the fossil fuels we have used for so long. Our
interest in biomass is driven by the belief that if we learn to use solar energy and
biology in a different way, we can address problems related to price, supply, and
the environmental impact of industrial activity.”

Dumesic’s research on environmentally friendly sources of common chemicals is
supported by the U.S. Department of Agriculture and the National Science Foundation.