Sunday, June 17, 2007

Hydroxymethylfurfural - A Substance For The Ages

Scientists have discovered the most effective method yet to convert glucose, found in plants worldwide and nature’s most abundant sugar, to HFM, a chemical that can be broken into components for products now made from petroleum. Image Credit: Pacific Northwest National Laboratory

Hydroxymethylfurfural - A Substance For The Ages

Oil has become the root substance of our modern society. The compounds not only fuel our automobiles, they are the building blocks that form plastics and chemical compounds that make modern life easier.

Corn and other plant material, when distilled to make Ethanol, have been heralded as the replacement for gasoline for our cars but what if we were able to use plant material for more … much more.

Well, scientists at the The Pacific Northwest National Laboratory in Richland Washington is a US Department of Energy (DOE) government research laboratory, have released an article to the journal, Science, that describes just this breakthrough.

Scientists have discovered the most effective method yet to convert glucose, found in plants worldwide and nature's most abundant sugar, to Hydroxymethylfurfural - HMF, a chemical that can be broken into components for products now made from petroleum.

Excerpts from press release issued from The Pacific Northwest National Laboratory (PNNL) -

Scientists get plastic from trees
Submitted by Vidura Panditaratne - PNNL - Fri, 2007-06-15

The researchers at PNNL-based Institute for Interfacial Catalysis, or IIC, took a giant step closer to the biorefinery when they 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
[Chief Scientist - Institute for Interfacial Catalysis, Pacific Northwest National Lab], senior author who led the research.

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 nature’s 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 the metal chlorides to convert the sugars to HMF. Ionic liquids provide an additional benefit: It is reusable, thus produces none of the wastewater in other methods that convert fructose to HMF.
“This, in my view, is breakthrough science in the renewable energy arena,” said J.M. White, IIC director and Robert A. Welch chair in materials chemistry at the University of Texas. “This work opens the way for fundamental catalysis science in a novel solvent.”

The chemistry at work remains largely a mystery, Zhang said, but he suspects that metal chloride catalysts work during an atom-swapping phase that sugar molecules go through called mutarotation, in which an H (hydrogen) and OH (hydroxyl group) trade places.
“The key is to take advantage of the open form to perform a hydride transfer through which glucose is converted to fructose.”

Zhang’s next step is to tinker with ionic solvents and metal halides combinations to see if he can increase HMF yield from glucose while reducing separation and purification cost.

“The opportunities are endless,” Zhang said, “and the chemistry is starting to get interesting.”

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