A sweet way to replace petroleum?

A variety of products now manufactured from petroleum could one day be made instead from simple sugar molecules, thanks to a new chemical process.

Compounds derived from petroleum are the chemical building blocks of many consumer goods, including plastics and pharmaceuticals. With the price of crude oil skyrocketing, researchers are on the lookout for alternatives, says Z. Conrad Zhang, a chemist at the Pacific Northwest National Laboratory in Richland, Wash. One promising candidate is a molecule called 5-hydroxymethylfurfural or HMF.

Chemists typically make HMF from fructose in a strongly acidic, water-based solution. Under such conditions, much of the HMF that forms quickly breaks down, and it’s difficult to purify what remains intact.

Now, Zhang and his colleagues have developed a technique to produce HMF efficiently, which they describe in the June 15 Science. Instead of stirring the ingredients into water, the researchers dissolved them in an ionic liquid, which consists solely of positively and negatively charged ions (SN: 9/8/01, p. 156). Adding various catalysts to the acidfree mix quickened the reaction and stabilized the HMF that was produced.

The team’s best results occurred when it cooked the fructose mixtures at 80°C for about 3 hours and used chromium chloride as a catalyst. Under those conditions, up to 83 percent of the fructose was converted into HMF, says Zhang.

Preliminary tests suggest that a variation of this process could generate HMF from the cellulose in wood and plant stems, says Zhang. Cellulose molecules are chains of fructose and glucose.