June 30, 2006 — A cheap and efficient process produces a chemical from fruit sugar that is remarkably similar to one that comes from petroleum.
The method, reported by professor James Dumesic of the University Wisconsin, Madison, could put plants such as corn on par with petroleum, reducing our dependency on the latter and creating more environmentally friendly products.
"The nice thing about using biomass as a replacement for all these petroleum products is that it is greenhouse-neutral," said Yuriy Roman-Leshkov, who with Dumesic and colleagues reported their findings in the current issue of Science.
When a plant-based product eventually decomposes or is burned — as in the case with fuel — it does not introduce additional carbon dioxide into the atmosphere, the way petroleum products do, he said.
It's a great idea, but finding an efficient, cost-effective way to turn the starch into other products is difficult.
Molecules that come from petroleum are easy to work with and can be strung together into different combinations to produce everything from the polyester of a leisure suit to the polypropylene of a fleece jacket to the polyethylene terephthalate of a 2-liter bottle of soda.
Petroleum molecules are also cost-efficient. Almost all of the petrochemical that goes into making a product ends up in the product, so there is very little waste.
But doing the same thing with biological molecules is not so easy.
"Biological molecules tend to be much more complex, so because of that, doing specific chemistry to make a specific molecule is more challenging," said Brent Shanks, associate professor of chemical and biological engineering at Iowa State University.
"You are going to have to develop new processing paradigms," he said. Shanks is not a member of the research team.
Dumesic and his colleagues think they have developed a new paradigm.
First, they dissolve sugar and water and then add a catalyst to the mix. Next, they mix in an organic solvent and heat it to 180 degrees centigrade.
The process causes the sugar to lose three water molecules, which simply blend in with the rest of the water. The leftover substance becomes the chemical hydroxymethylfurfural, or HMF.
HMF looks and behaves a lot like a petroleum-based molecule and could be strung together in different combinations to produce plastics and fuels.
The challenge, said Shanks, will be to get industry to adopt HMF. Although it functions similarly to petroleum-based chemicals, it's still slightly different.
"Can the industry reconfigure to handle those slightly different properties?" he asked. "At the end of the day, it's all about cost."
