RICHLAND, Wash. -- It has been an elusive goal for the legion of chemists trying to pull it off: Replace crude oil as the root source for plastic, fuels and scores of other industrial and household chemicals with inexpensive, nonpolluting renewable plant matter.
Scientists took a giant step closer to the biorefinery this week, reporting in the June 15 issue of the journal Science that they have directly converted sugars ubiquitous in nature to an alternative source for those products that make oil so valuable, with very little of the residual impurities that have made the quest so daunting.
What we have done that no one else has been able to do is convert glucose directly in high yields to a primary building block for fuel and polyesters, said Z. Conrad Zhang, senior author who led the research and a scientist with the PNNL-based Institute for Interfacial Catalysis, or IIC.
That building block is called HMF, which stands for hydroxymethylfurfural. It is a chemical derived from carbohydrates such as glucose and fructose and is viewed as a promising surrogate for petroleum-based chemicals.
Glucose, in plant starch and cellulose, is natures most abundant sugar. But getting a commercially viable yield of HMF from glucose has been very challenging, Zhang said. In addition to low yield until now, we always generate many different byproducts, including levulinic acid, making product purification expensive and uncompetitive with petroleum-based chemicals.
Zhang, lead author and former post doc Haibo Zhao, and colleagues John Holladay and Heather Brown, all from PNNL, were able to coax HMF yields upward of 70 percent from glucose and nearly 90 percent from fructose while leaving only traces of acid impurities. To achieve this, they experimented with a novel non-acidic catalytic system containing metal chloride catalysts in a solvent capable of dissolving cellulose.
The solvent, called an ionic liquid, enabled t
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Contact: Bill Cannon
cannon@pnl.gov
509-375-3732
DOE/Pacific Northwest National Laboratory
14-Jun-2007