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Plastic that grows on trees

Fuel, polyester and other chemicals from biomass get a giant boost, PNNL team reports in the journal Science

Contact: Bill Cannon
cannon@pnl.gov
509-375-3732
DOE/Pacific Northwest National Laboratory

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 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.

Metal chlorides belong to a class of ionic-liquid-soluble materials called halides, which “in general work well for converting fructose to HMF,” Zhang said — but not so well when glucose is the initial stock. In fact, attempts at direct glucose conversion created so many impurities that it was simpler to start with the fructose, less common in nature than glucose.

Zhang and his team, working with a high-throughput reactor capable of testing 96 metal halide catalysts at various temperatures, discovered that a particular metal — chromium chloride — was by far the most effective at converting glucose to HMF with few impurities and, as such reactions go, at low temperature, 100 degrees centigrade.

“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 hydrogen-hydroxyl position-switch that allows the catalytic conversion was verified by nuclear magnetic resonance performed at the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility located at PNNL. During the swap, the molecule opens, Zhang said.

“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.”

http://www.eurekalert.org/pub_releases/2007-06/dnnl-ptg061207.php

Yes well I am sure its all very technical, but is it really worthwhile?
To produce plastics, diesel, and fuel from Bio-mass does lower the carbon dioxide (C02) pollutants.
But I have this bad idea in the back of my mind that if the cutting down of forests to make way for the planting of Rape and other oil bearing plantations continues. The poorer countrys sometime soon, are going to find themselves short of food and starve, as basic food prices rise.
There wont be much point in certain Countrys being able to meet their Kyoto agreements, (when it come into force in a few years time)If they dont have any land left to grow the basic foods to export/sell to those dozens of African and Asian countrys that already need to import their foods.
No one seems to talk about this...but its a study worth while persuing.

The United States hit that threshold last year or the year before. We are at the point of importing more food than we export. China is dumping food products on our market driving our farmers out of business. Their only recourse is the sell the land for development. Most of the environmental movement is funded by large foundations that over seas interests in agriculture, timber and oil.

Oh! Thats bad news, I didnt realise that USA is on the point of importing more food.
The great thing about the US is that, its one of the few countrys in the world that could go into isolation, because it is self sufficient in just about everything. or so we believe here in Europe.
I can remember not too many years ago when America used to give away its surplus wheat to China.
Maybe things have changed in China these days--OR-- could there be some relation in the fact that- "a fifth of Americas corn crop is now being used to produce four billion gallons of Ethanol, compared with targets of 12 billion gallons by 2012"
That was a statement made by Rex Tillerson, the Chief Executive of ExxonMobile, speaking at the Royal Institute for International Affairs in London yesterday.
He also said that the world energy demand would rise by 45% by 2030, and fossil fuels- oil, natural gas and coal- were the only energy recources of sufficient size, adaptability and affordability to meet the world needs. He stated that he was sceptical of the drive by Goverments to increase the use of Biofuels.

***Thoughts
Well if Biofuel production means shortage of food i.e Corn.etc
I agree with him.

No, the USA does not have natural resources. Well we do but we are not allowed to use them. Can’t log because of the owl and salmon. Can farm because pesticides and fertilizers are hurting the fish or red legged frog or fairy shrimp. Can’t drill unless you are the Nature Conservancy. Can’t mine, damages the environment. Can’t build refineries causing gas shortages. Can’t build Nukes. There’s the old environment thing again.

And just who is pushing for stronger environmental regulations? Well the enviro groups are all funded by the large foundations that have investments in all of this stuff in other countries.

Do you remember the big roil over here about Pres. Clinton getting campaign money from the Chinese etc? Well one of his biggest contributors was the Riady family in Indonesia. There are two places in the world that have clean burning coal. One was on land set aside as a wilderness area by Pres. Clinton. The other is owned by the Riady family of Indonesia.

I’ll see if I can find a link to the article about reaching the food import threshold.