2,5-Dimethylfuran

2,5-Dimethylfuran is a heterocyclic compound of the formula C₆H₈O. A derivative of furan, it is also known by its abbreviation DMF, not to be confused with dimethylformamide. Recent advances have increased its attractiveness as a biofuel.

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Production

Recent research has resulted in improved and more efficient production methods that convert fructose or glucose to a key building block of 2,5-dimethylfuran - hydroxymethylfurfural - in a catalytic biomass-to-liquid process.

Research into an acid catalyst method, undertaken by scientists from the University of Wisconsin-Madison, was published in Science on June 30, 2006,^[1] and in Nature on June 21, 2007.^[2][3]

Another team from Pacific Northwest National Laboratory have developed a non-acidic catalytic method, reported in Science on June 15, 2007.^[4][5] Although it produces a lower yield, glucose can also be used in the processes.

Potential as a biofuel

DMF has a number of attractions as a biofuel. It has an energy density 40% greater than ethanol, making it comparable to gasoline (petrol). It is also chemically stable and, being insoluble in water, does not absorb moisture from the atmosphere. Evaporating dimethylfuran during the production process also requires around one third less energy than the evaporation of ethanol,^[6][2] although it has a boiling point some 14 °C higher, at 92 °C, compared to 78 °C for ethanol.

The ability to efficiently and rapidly produce dimethylfuran from fructose, found in fruit and some root vegetables, or from glucose, which can be derived from starch and cellulose - all widely available in nature - is likely to add to the attraction of dimethylfuran once safety issues have been examined. Bioethanol and biodiesel are currently the leading liquid biofuels.

Other uses

2,5-Dimethylfuran acts as a scavenger for singlet oxygen, a property which has been exploited for the determination of singlet oxygen in natural waters. The mechanism involves a Diels-Alder reaction followed by hydrolysis, ultimately leading to diacetylethylene and hydrogen peroxide as products. More recently, furfuryl alcohol has been used for the same purpose.^[7]

This compound has also been proposed as an internal standard for NMR spectroscopy. This is due to its good intrinsic properties. 2,5-Dimethylfuran has two singlets in its NMR spectrum at δ 2.2 and 5.8; the singlets give reliable integrations, while the positions of the peaks do not interfere with most analytes. The compound also has an appropriate boiling point of 92 °C which prevents evaporative losses, yet is easily removed.^[8]

Toxicology

2,5-Dimethylfuran, together with 2,5-hexanedione and 4,5-dihydroxy-2-hexanone, is one of the main metabolites of hexane in humans, which play a role in the mechanism for the neurotoxicity of hexane.^[9]

2,5-Dimethylfuran has been identified as one of the components of cigar smoke with low cilatoxicity (ability to adversely affect the cilia in the respiratory tract that are responsible for removing foreign particles). ^[10] Its blood concentration can be used as a biomarker for smoking.^[11]

Role in food chemistry

2,5-Dimethylfuran can be formed from the thermal degradation of sugars, and has been identified in trace amounts as a component of caramelized sugars.^[12]

References